by Donald Rapp
In a recent paper, Ellis and Palmer (2016) proposed that deposition of dust on giant ice sheets, thus reducing their albedo, was a principal factor in the termination of Ice Ages over the past 800 kyrs.
Background
The origin and causes of quasi-periodic Ice Ages over the past ~800,000 years is an intriguing topic that has fascinated many scientists. Many hundreds of papers have been published, and a consensus has grown that a key factor is the so-called Milankovitch model of variable solar input to high northern latitudes dues to wobbles in the Earth’s orbit. While this model has significant resemblance in outline to the ice core and sediment data, there are also some notable exceptions and deviations. The most difficult thing to explain is why Ice Ages end at all, and particularly why they end so suddenly.
In reviewing the literature on understanding Ice Ages, I find a great deal of concentration on variable solar input to high northern latitudes, and the role of changing CO2 concentration, but rather less on the role of dust. Models that did include dust usually were limited to the effect of suspended dust in the atmosphere, rather than dust deposited on ice sheets. Compendiums reviewing the topic of Ice Ages typically downplay the role of dust. For example, the review by Berger and Qin (2012) does not contain the word “dust”. Even my own book (Rapp, 2012) contains only a minimal discussion of glacial dust. Yet a few papers, especially those of Ganopolski et al. mentioned the importance of dust deposition on ice sheets as an important factor in termination of Ice Ages.
In a recent paper, Ellis and Palmer (2016) proposed that deposition of dust on giant ice sheets, thus reducing their albedo, was a principal factor in the termination of Ice Ages over the past 800 kyrs. In their model, terminations occur when extreme dust buildup occurs in an aging Ice Age simultaneously with a sharp rise in solar intensity, They presented arguments in favor of this hypothesis based on previously available data from ice cores showing a large buildup of dust prior to termination of Ice Ages, as well as some dubious reworking of Milankovitch-type solar variability. However, Ellis and Palmer (2016) only reported briefly on previous work in regard to the connection between dust deposition and Ice Age terminations, and it seems worthwhile to review the data and models related to dust deposition developed prior to their paper, to establish a foundation before reviewing the thesis of Ellis and Palmer (2016).
Review of Previous Work
Starting around the 1990s, a number of investigators attempted to analyze glacial cycles using global climate models. In such work, they attempted to account for all of the factors that produced “forcings” that induced climate change in the glacial cycle, including the effects of dust. Many of the earlier papers dealt only with the effect of suspended dust in the atmosphere – producing a net cooling effect by reflection of sunlight. A few however, did include with deposition of dust on ice sheets as an important factor in termination of Ice Ages.
Peltier and Marshall (1995) said:
… our analyses suggest that the albedo variations in the ice-sheet ablation zone caused by dust loading may represent an extremely important ablation mechanism. Using our parameterization of “dirty” snow in the ablation zone we find glacial retreat to be strongly accelerated, such that complete collapse of the otherwise stable Laurentide ice sheet ensues.
Overpeck et al. (1996) said:
Our results point to dust aerosols as a potential source of episodic warming during the last glacial period, and suggest that this warming might be the trigger mechanism needed to account for previously unexplained major abrupt climate events.
Thus, mineral dust appears to have been the most globally distributed aerosol, with the largest radiative effect over snow- and ice-covered regions.
Except for regions of northern Canada and Alaska, the dust-induced average annual warming was greater at progressively higher latitudes, and was greatest (up to 4.4°C) in regions with dust over high-albedo snow- and ice-covered areas.
Calov et al. (2005) said:
Dust affects climate dynamics by reducing the albedo of snow and ice. This feedback presumably is a negative one, at least at some stages of the glacial cycle, because an increase of ice volume leads to a dryer climate, to an increase of dust generation and hence, deposition, thereby lowering snow albedo and amplifying snowmelt.
Krinner et al. (2006) used a general circulation model with high regional resolution and a parameterization of snow albedo to show that
…ice-free conditions in northern Asia during the LGM were favored by strong glacial dust deposition on the seasonal snow cover. Our climate model simulations indicate that mineral dust deposition on the snow surface leads to low snow albedo during the melt season. This, in turn, caused enhanced snow melt and therefore favored snow-free peak summer conditions over almost the entire Asian continent during the LGM, whereas perennial snow cover is simulated over a large part of eastern Siberia when glacial dust deposition is not taken into account.
Ganopolski et al. (2010) used a high-resolution climate model that “directly accounts for the effect of dust deposition on snow albedo” to analyze the evolution of the most recent Ice Age from about 130 kya to the present. They assumed some rather high dust deposition rates. They went on to say:
In reality, most of the dust associated with glacial erosion is deposited during summer; hence, the concentration of dust in the upper snow layer during snowmelt is expected to be much higher than it would be in case of uniform mixing over the year. Moreover, when snow melts, only a fraction of dust is removed by melt water and therefore the concentration of dust in snow increases with time. Although the accurate modeling of all of these processes is problematic, related uncertainties are not crucial, because a saturation effect occurs for dust concentration in snow of more than 1000 ppmw and the albedo of snow reaches a value comparable to that for dirty ice.
They included both globally transferred dust as well as glaciogenic dust that “originates from the southern flanks of the ice sheets and this source is significant only for mature ice sheets, which reach well into areas covered by thick terrestrial sediments.” Their model produced an Ice Age that increased in extent from 130 kya to 20 kya, although there were some vacillations in the growth of ice sheets. “Deglaciation began soon after 20 kya and accelerated significantly after 16 kya.” Their estimate of the dust deposition rate during the most recent Ice Age peaked at the LGM about 20 kya at 40 to 60 g/m2-yr. Their model indicated that without inclusion of glaciogenic dust, the ice sheets would have shrunk by 60% over the past 20,000 years but would not disappear. With inclusion of glaciogenic dust, the ice sheets would totally disappear about 8,000 years ago. They concluded:
Hence, at least in our model, accounting for the additional source of dust related to the glacial erosion is crucial for simulating of a complete termination of the glacial cycle …
When they changed the amount of dust deposition, the effect was not great. A small amount of dust was necessary to terminate the Ice Age, but adding more dust had a smaller effect.
Ganopolski et al. (2011) extended the work of Ganopolski et al. (2010) to cover the Ice Ages over the past 800,000 years, using the same model. Their results indicated:
Each glacial termination is associated with a large increase in dust deposition, which reduces surface albedo and enhances ablation. There are two main reasons for the increase in the dust deposition rate during glacial termination: (i) a considerable portion of the North American ice sheet at the glacial maxima spreads over the area covered by thick terrestrial sediments and (ii) most of the ice sheet base over this area is at the pressure melting point. Both of these factors enable fast sliding of the ice sheets and a large sediment transport towards the ice margins which, in turn, lead to enhanced glaciogenic dust production and dust deposition over the ice sheets. This amplifies the direct effect of rising summer insolation and GHG concentration.
It is not very clear from reading Ganopolski et al. (2011) how they set the dust loading as a function of year across 800,000 years. Ganopolski and Calov (2012) mentioned:
The dust deposition is computed as the sum of the background dust deposition, taken from GCM simulations, and the deposition of glaciogenic dust, which is interactively computed in the CLIMBER- 2 model (Ganopolski et al. 2010).
Nevertheless, if we take their results at face value, we can examine the relation between dust levels and termination of Ice Ages as provided by their model. Figure 1 shows their results comparing the rate of dust deposition with the ice volume.
Figure 1. Comparison of modeled dust loading (g/m2-yr) (brown curve) with ice volume (meters of global eustatic sea level equivalent) (blue curve).
Figure 2. Comparison of modeled dust loading (g/m2-yr) (red curve) with ice volume (meters of global eustatic sea level equivalent) (blue curve) showing peaks of dust loading as vertical dotted lines.
It is interesting to compare the modeled dust loading with ice volume in greater detail as shown in Figure 2. The Ice Ages are outlined by the blue lines, while the rate of dust deposition is outlined by the red lines. It is immediately obvious that terminations of Ice Ages are typically preceded by spikes in the dust deposition rate. Furthermore, there is typically a short delay between the dust spike and the rapid termination of the Ice Age. In Figure 2, a vertical brown dotted line is drawn through each spike in dust loading, and the spikes are labeled A through U. The relationship of each dust spike to the ice volume curve is summarized in Table 1.
We note the following:
(1) Not all Ice Ages were of equal duration and were not perfectly regularly spaced. Yet, there is similarity between most of the Ice Ages, and the periodicity, though far from perfect, is suggestive of roughly 100,000 years.
(2) Occasionally, significant increases in ice volume occur between Ice Ages, but these are typically short-lived (G and Q; no highlight).
(3) Textbook cases where a high dust spike immediately precedes a sudden termination of an Ice Age included six cases: A, C, F, L, S and U (yellow highlight). Three other terminations followed medium dust spikes (I, N and P)(orange highlight).
(4) In seven cases (B, D, J, K, M, O and R) a minor dip in the dust loading produced a minor dip in ice volume – as expected (green highlight).
(5) There were several anomalous cases where the magnitude of the change in ice volume was disproportionate to the change in dust loading: E, G, H, Q and T (no highlight).
Table 1. Relationship of the dust spikes to the ice volume curve.
Thus the model of Ganopolski et al. (2011) indicated a primary relationship between a high spike in dust loading followed shortly by a precipitous drop in ice volume. There are some anomalies in this picture, as we have shown, but by and large, the relationship between dust loading and termination of Ice Ages seems to be firmly predicted by their model.
As Ganopolski et al. (2011) pointed out:
As was shown by Ganopolski et al. (2010), simulation of a complete glacial termination, even with the prescribed GHG forcing, is only possible when the deposition of glaciogenic dust is taken into account.
The explanation of glacial termination requires an additional strong nonlinear mechanism, which, in our case, is the dust feedback. This feedback is activated after the ice sheets spread well into the area covered by thick terrestrial sediments. High rates of dust deposition over the ice sheets reduce their albedo, which enhances ablation and thus amplifies the ice sheet response to rising insolation. Note that this mechanism was already proposed by Peltier and Marshall (1995) …
Ganopolski and Calov (2012) reviewed their previous work and concluded:
Switching off the effect of the dust deposition on snow albedo leads to a rapid development of unrealistically large ice sheets, which cannot be melted even during periods of high CO2 concentration and summer insolation. This confirms our earlier speculation (Calov et al. 2005) about the importance of eolian dust in restriction of growth of the ice sheets and their rapid terminations
The model explicitly accounts for the direct radiative forcing of the atmospheric dust and the effect of dust deposition on snow albedo. The latter, as shown in Calov et al. (2005) and Ganopolski et al. (2010), plays an important role in controlling the spatial extent of the ice sheets and the rate of deglaciation.
The dust deposition is computed as the sum of the background dust deposition, taken from GCM simulations, and the deposition of glaciogenic dust, which is interactively computed in the CLIMBER- 2 model (Ganopolski et al. 2010).
Switching off the effect of the dust deposition on snow albedo leads to a rapid development of unrealistically large ice sheets, which cannot be melted even during periods of high CO2 concentration and summer insolation. This confirms our earlier speculation (Calov et al. 2005) about the importance of eolian dust in restriction of growth of the ice sheets and their rapid terminations.
Bauer and Ganopolski (2014) investigated further into the role of dust in glacial cycles. Among the many factors they discussed, the forcing due to dust and the source of dust in their model was presented. Their modeled forcing due to dust deposition on ice sheets is shown in Figure 3. This dust forcing is compared to a measure of relative temperature at EPICA-Dome in Figure 4.
Figure 3. Modeled forcing due to dust deposition on ice sheets by Bauer and Ganopolski (2014).
Figure 4. Comparison of modeled dust forcing by Bauer and Ganopolski (2014) with relative EPIC-Dome temperatures.
Ganopolski and Brovkin (2015) analyzed the most recent four Ice Ages with their model. However, instead of using the actual Antarctic dust data as input to the model, they used their own dust model that was strangely different with generally lower dust levels than the measured values. Although their paper said:
… the dust cycle model simulates atmospheric dust loading and dust deposition rate. The latter affects surface albedo of snow and iron fertilization effect in the South Ocean.
They did not mention further the role of dust deposition.
Throughout the work of Ganopolski and co-workers from 2010 through 2014, they included dust deposition as one factor, along with other inputs to the model, but did not generally single out the relative importance of dust loading in terminations, although they did emphasize that terminations could not occur without dust deposition.
Evidently these models imply a strong connection between dust deposition on ice sheets and termination of Ice Ages. However, other studies have not necessarily placed emphasis on dust in terminations. For example, Claquin et al. (2003) took the opposite view:
Although the net effect of dust over ice sheets is a positive forcing (warming), much of the simulated high-latitude dust was not over the ice sheets, but over unglaciated regions close to the expanded dust source region in central Asia.
In 2012, a book was published entitled “Climate Change Inferences from Paleoclimate and Regional Aspects” with articles by a number of prominent paleoclimatologists (Berger et al., 2012). Several articles in this book did not acknowledge an important role of dust deposition in terminations.
In this same volume, an article by Hansen and Sato attempted to estimate the climate sensitivity of the Earth by comparing conditions at the last glacial maximum (LGM) with modern pre-industrial times. Using known and estimated differences in temperature, CO2 concentration, and other parameters, they calculated various forcings involved in the transition from the LGM to modern times. They did not seem to include deposition of dust on ice sheets as a major forcing; yet as Figures 1 and 2 show, there was a remarkable rise in modeled atmospheric dust prior to the termination of the LGM.
A scan of Zweck and Huybrechts (2005) and Roche, et al. (2012) reveals that the words “dust” and “termination” did not appear once in their papers. Clark et al. (2012) does not contain the word “dust” yet its title is “Global climate evolution during the last deglaciation”.
Heinemann et al. (2014) attempted to model the termination of the last Ice Age. They said:
Paleoclimate data and model studies indicated that the atmosphere during the LGM transported more dust than at present (Mahowald et al., 1999, and references therein). Dust, while it is in the atmosphere, can increase the planetary albedo, which causes a cooling. Dust deposition on snow reduces their albedo, which causes a warming. None of these processes are accounted for in the present study. (Emphasis added).
Hence the strong emphasis placed on dust deposition in terminations by Ganopolski and co-workers was not universally shared by other investigators.
Ellis and Palmer (2016) Concept
In 2016, Ellis and Palmer published a paper that could prove to be important. In this paper they emphasized the importance of dust deposition as a trigger to initiate terminations of Ice Ages.
As Ellis put it (private communication):
Almost everyone agreed that Milankovitch cycles controlled the glacial cycle. But they were unable to explain why some cycles failed to produce an interglacial while others did, and during subsequent research it became apparent that there was no accepted answer to this troubling but central question. A theory is not a theory, if it has a thumping great lacuna in the middle of it. This led me into a detailed study of the glacial cycle, and the revelation dust was at a peak just before each interglacial.
It was only when Michael Palmer sought to refine my rough and rugged draft paper, that the prior research of Mahowald and Galopolski and many others was discovered. And it was surprising that all of these papers danced around what I saw as the central agent of ice age modulation, without identifying and explaining it as such. Ganopolski, for instance, identified a link between ice sheet volume and dust and presumed that the volume of ice was causing the dust – in other words this must have been glaciogenic dust caused by ice-rock erosion. But previous papers had already identified the source of the dust as the Gobi and Taklamakan deserts, excluding the possibility that the dust was glaciogenic.
A key observation made by Ellis and Palmer (2016) was:
When CO2 reaches a minimum and albedo reaches a maximum, the world rapidly warms into an interglacial. A similar effect can be seen at the peak of an interglacial, where high CO2 and low albedo results in cooling. This counterintuitive response of the climate system also remains unexplained, and so a hitherto unaccounted for agent must exist that is strong enough to counter and reverse the classical feedback mechanisms.
They proposed:
The answer to both of these conundrums lies in glacial dust, which was deposited upon the ice sheets towards the end of each glacial maximum… during the glacial maximum, CO2 depletion starves terrestrial plant life of a vital nutrient and causes a die-back of upland forests and savannahs, resulting in widespread desertification and soil erosion. The resulting dust storms deposit large amounts of dust upon the ice sheets and thereby reduce their albedo, allowing a much greater absorption of insolation.
They asserted their proposal:
… explains each and every facet of the glacial cycle, and all of the many underlying mechanisms that control its periodicity and temperature excursions and limitations.
which of course is not as absolute as all that; yet the proposal does have considerable potential merit.
The paper by Ellis and Palmer then goes off on a tangent regarding variability of solar input to high latitudes, which is very heavily traveled ground, and we need not discuss this here. But one point they raised is worth emphasizing: One cannot invoke rising solar input to high latitudes as the sole cause of terminations of Ice Ages since many such increases in solar input do not produce terminations. Increased solar input might be necessary for terminations but is clearly not sufficient.
The essential basis for the hypothesis advanced by Ellis and Palmer is illustrated in Figure 5. The vertical scales are not specified since they are not essential to the argument at this point. Part (C) shows the dust loading in the ice core at Antarctica (using binned data to reduced scatter). Vertical red dashed lines are drawn at each of the major peaks in the dust loading. It can be seen that these red dashed lines align with the sharp minima in Antarctic temperature in Part (A) of the figure. These minima immediately precede rapid increases in Antarctic temperature with a time lag between the peak in dust load and the rise in temperature of several thousand years. The times associated with the rapid increases in temperature are drawn as vertical black dashed lines in Part (B), the solar intensity on June 21 at 65°N latitude. These black dashed lines coincide with rising solar intensity in every case. Therefore the inference made by Ellis and Palmer is that two situations are necessary precursors to a termination of an Ice Age:
(1) There must be a sharp maximum in dust loading.
(2) The sharp dust maximum must coincide with sharply rising solar intensity.
Note particularly that rising solar intensity by itself does not necessarily lead to a termination. Many such rising lobes of solar intensity do not lead to termination. Furthermore, some very high rising lobes of solar intensity have no effect at all on continuity of Ice Ages. Therefore, one might infer that peak dust is even more important than solar intensity in termination of Ice Ages. While these inferences do not in themselves prove a cause–effect relationship, they are highly suggestive.
At this point in their paper, Ellis and Palmer developed a “side bar” discussion of the role of CO2 feedback in glacial-interglacial cycles. This discussion was not germane to their main thesis and is not considered here.
Figure 5. (A) Antarctic temperature. (B) Solar intensity at 65°N on June 21. (C) Dust loading in Antarctica ice core. (All three graphs shown with arbitrary scale)
Validation of the Hypothesis Of Ellis and Palmer
Having established a connection between dust levels and terminations of Ice Ages, the next step is to attempt to quantitatively validate the hypothesis that dust deposition is a principal cause of termination of Ice Ages, by estimating the amount of dust deposited on the ice sheets, and showing that such levels of dust deposition would exert sufficient warming forces to initiate terminations of Ice Ages. Unfortunately, the data are sparse, and one must be content with limited data and approximate models to show support for the hypothesis. Nevertheless, it is important to examine the limited data that are available to assess the validity of the hypothesis to the extent possible.
In the present review, it is desired to keep two aspects of the dust deposition hypothesis separate: (1) levels of dust deposition, and (2) changes in ice albedo due to dust deposition at any level. Ellis and Palmer (2016) tended to discuss both aspects in together, but I will attempt to extract their discussions into two separate sections.
Levels of Dust Deposition on Ice sheets
Ellis and Palmer (2016) pointed out that dust levels within Antarctic ice cores average only 0.8 ppm at peak dustiness, yet the effects of low levels of dust have been demonstrated to be significant. Dust levels at Ngrip in Greenland peaked at about ten times that level shortly before the LGM, as shown by Ruth et al. (2007). The peak dust loading was 8 ppm. The data of Ruth et al. (2007) are shown in Figure 6.
Ellis and Palmer made the assumption that the dust concentration in the ice at the southern flank of the ice sheets during the LGM was about three times that in Greenland at 75°N. That is a reasonable guess. On the other hand, precipitation of snow was likely to be much greater at the lower latitudes, thereby somewhat masking the increased dust load. The claim regarding relative dust deposition in the Great Lakes area vs. Central Greenland depends to some extent upon how one reads the blue colors in Plate 5b of Mahowald et al. (1999). With this assumption, dust loading on the ice sheets might have reached as high as about 25 ppm.
Figure 6. Dust loading from Greenland ice core.
Relation Between Dust Deposition Rate and Dust Loading in Ice Cores
Ganopolski et al. (2010) indicated an annual precipitation rate of 500 mm/yr, while Gildor et al. 2014 estimated 400 mm/yr on the ice sheets during the LGM. The density of snow can vary widely depending on how it packs. Assuming a snow density of roughly 500,000 g/m3, the deposition of snow was roughly 0.5 ´ 500,000 = 250,000 g/m2-yr.
For every g/m2-yr of dust deposited, the ice cores would contain 1/250,000 or 4 ppm.
Ganopolski et al. (2010) modeled the peak dust deposition rate at the LGM to be about 50 g/m2-yr (see Figure 7). That would correspond to ice cores containing 200 ppm, which seems to be far in excess of reality.
If the peak dust loading were about 25 ppm as estimated by Ellis and Palmer, that would correspond to a dust deposition rate of roughly 6 g/m2-yr.
Ganopolski et al. (2010) suggested that the dust is not uniformly mixed with snow over the whole year. They said:
In reality, most of the dust associated with glacial erosion is deposited during summer; hence, the concentration of dust in the upper snow layer during snowmelt is expected to be much higher than it would be in case of uniform mixing over the year. Moreover, when snow melts, only a fraction of dust is removed by melt water and therefore the concentration of dust in snow increases with time.
It is noteworthy that Mahowald et al. (1999) estimated the dust deposition rate for both Greenland and a “miscellaneous ice core” (Plate 6b of their paper) to be about 10 g/m2-yr during the LGM. This is a factor of five lower than the estimate of Ganopolski et al. (2010) and closer to the estimate by Ellis and Palmer. Figure (1c) of Albani et al. (2016) indicated that the LGM dust deposition rate was about
10 g/m2-yr at the lower end of the Laurentide ice sheet, decreasing gradually to about 1 g/m2-yr at the northern end of the ice sheet. At the other end of the scale, Figure 4 of Takemura et al. (2009) indicates “Arctic” deposition as about 0.2 g/m2-yr during the LGM, but this is only about a factor of two higher than at present, and seems unlikely.
Figure 7. Simulated temporal evolution of annual dust deposition rates in the grid cell south of the Laurentide Ice sheet (blue) and south of Fennoscandian ice sheet (red). (Ganopolski et al., 2010).
Most of the dust was presumably deposited during summer. It is possible that there was relatively little snow deposition during summer. Therefore during the dust might have been deposited with little or no admixture of snow, increasing the concentration on the surface during the summer months.
As Palmer put it (private communication):
For glacial termination to go all the way, it seems important that the ice sheets have become saturated, or mostly saturated, with dust from top to bottom. Deposition of fresh dust drops off steeply in the early stages of deglaciation; the continuing melt-off is thus not sustained by fresh dust but must instead be carried by the old dust that is exposed layer by layer by the melt-off itself. Of course, the old dust gets covered by new snow in the winter, but the strong high latitude insolation may be enough to break through this fresh snow cover even without strong fresh dust deposition. (Maybe this is the crucial role of the strong insolation – to break through each year’s fresh snow cover and get back to work on the old dirty ice underneath.)
In this context, it would be important to understand not only how much dust was dropped on the ice sheets during a glacial maximum, but also how many millennia it took for a freshly deposited layer of dirty snow to reach the bottom of the ice sheets.
It seems reasonable to assume that this occurred faster in the big glacial ice sheets than it does now in Greenland, but this is difficult to model. The same goes for modeled dust deposition rates; my impression is that there is altogether too much modeling and too little evidence collection going on in paleoclimatology.
Blocking Area of Deposited Dust
Following Mahowald et al. (1999), if it is assumed that the average dust particle diameter is 2.5 microns, the blocking area of a dust particle is estimated to be
3.14 ´ (1.25 ´ 10-6) m2 ~ 5 ´ 10-12 m2.
And the mass of a dust particle is estimated to be
4/3 ´ 3.14 ´ (1.25 ´ 10-6)3 m3 ´ 1.5 ´ 106 g/m3} = 1.2 ´ 10-11 g
If the dust deposition rate were as high as estimated by Ganopolski et al. (2010), namely 50 g/m2-yr, the number of dust particles per m2 would be 50/(1.2 ´ 10-11) = 4 ´ 1012. The total blocking area of this number of particles would be
4 ´ 1012 ´ 5 ´ 10-12 m2 = 20 m2 per square meter. The surface of the ice sheet would be covered with multiple layers of dust. Even for a dust deposition rate of 6 g/m2-yr, as estimated by Ellis and Palmer (2016) the blocking area of annual dust would be 2.5 m2 per square meter. Thus, the estimated levels of dust on the ice sheets at LGM were enough to make them appear very dusty.
Source of the Dust
Ellis and Palmer (2016) reviewed data and models on the source of dust and albedo effects of dust during Ice Ages. I will be content with a very brief mention of a few points. There seems little doubt that the combination of low temperature and low CO2 was detrimental to plant life. They claimed the principal impact was on high altitude regions, normally arid regions, and northern regions during summer. The source determined by isotopic analysis was attributed to the Gobi and Taklamakan deserts, and there was little evidence of glaciogenic dust. As Ellis put it (private communication):
The question is how these peaks in dust flux were generated during the latter millennia of each ice age. If it was not the grinding of ice sheets that caused the dust, then what did? The likely answer was that the low CO2 concentrations at each glacial maximum led to plant extinction in high altitude arid regions, turning them into new CO2 deserts. And this was a scenario that fitted the source region for Greenland dust very well – the Gobi. The Gobi is mostly steppe grassland, but under the low CO2 conditions of a glacial maximum the entire Gobi became a shifting-sand desert that created vast dust clouds, as is proven by the massive dust deposits upon the Loess Plateau in China.
And so the beauty of this theory and paper is that it is a simple thought-experiment that can be followed by anyone, and yet in my view it explains every facet the glacial-interglacial cycle. And it even explains the previously inexplicable – the reason why some strong precessional insolation maxima failed to produce much in the way of melting and warming, let alone an interglacial.
In short:
Ice ages cause ice sheet extension –> oceanic cooling –> oceanic CO2 absorption = plant asphyxiation on the Gobi plateau –> new CO2 deserts –> dust generation –> ice sheet contamination for 10 kyrs.
Then:
Rising NH Milankovitch insolation –> ice sheet surface ablation and melting –> ice sheet dust exposure and concentration –> ice sheet albedo reduction –> increased insolation absorption –> increased ablation and melting –> interglacial.
It is a simple feedback system that is very powerful and operates regionally, unlike CO2 which is a global feedback agent of indeterminate strength. And yet we know that interglacials are regional phenomena rather than global phenomena, because they only coincide with increased Milankovitch insolation in the northern hemisphere, and never with increased insolation in the south. Ergo, the primary feedback controlling interglacial inception must be regional to the NH, rather than global.
Summary
The hypothesis put forth by Ellis and Palmer (2016) has considerable potential merit. The role of dust in terminations of Ice Ages is probably far more important than many realize. It appears likely that unusually high dust levels coupled to sharply rising solar intensity at high latitudes was a major factor in initiating termination of Ice Ages. As Palmer put it, layers of buried dust probably sustained the evolution of the interglacial period.
Moderation note: As with all guest posts, please keep your comments civil and relevant.
There are lots of theories about the termination of the ice ages. I find it difficult to understand how “orbital theories” for ice age termination can be put forward with high confidence by IPCC AR5.
I examine some theories in <a href="https://scienceofdoom.com/2014/03/03/ghosts-of-climates-past-eighteen-probably-nonlinearity-of-unknown-origin/" Ghost of Climate Past – Eighteen – “Probably Nonlinearity” of Unknown Origin – what is believed and what is put forward as evidence for the theory that ice age terminations were caused by orbital change.
The dust theory is an interesting one.
That link didn’t show up correctly – here it is again:
https://scienceofdoom.com/2014/03/03/ghosts-of-climates-past-eighteen-probably-nonlinearity-of-unknown-origin/
Yes. A few weeks ago, I read through your very extensive and very competent interpretative review of almost everything that has been written about Ice Ages. As you show, the Milankovitch-type analyses seem to represent some part of the reality of Ice Age transitions, but far from perfectly, and the exceptions are often in regard to terminations. Obviously, you covered a far more complete review of previous work than I did. But my review was narrowly focused on the role of dust in terminations. The CO2 enthusiasts, believing that the answer to terminations must lie in CO2, typically postulate a mysterious evolution of large amounts of CO2 (often from the southern oceans) as a sort of deus ex machina to trigger initiation of terminations. Terminations remain the Achilles heel of Ice Age theory and I think Ellis has hit on an important potential aspect. In posting this report, I hoped, that experts like you might provide further insights and possibly references we were not aware of.
Donald
“The CO2 enthusiasts, believing that the answer to terminations must lie in CO2, typically postulate a mysterious evolution of large amounts of CO2 (often from the southern oceans) as a sort of deus ex machina to trigger initiation of terminations.”
I’ve never seen that put forward in any of the many papers I’ve read on the ice ages. The most common theory is changes in high latitude northern insolation starts the process. This has the problem – noted by many – that the warming started in the southern hemisphere.
The “CO2 problem” is the large change in CO2 concentrations that can’t easily be explained. Obviously it creates some positive feedback (more CO2, more warming) but the changes in CO2 concentrations over ice age cycles are currently a mystery.
>>This has the problem – noted by many – that the
>>warming started in the southern hemisphere.
I am working on this aspect at the moment. A possible reason is that during the last interglacial obliquity insolation increases preceded precessional insolation, and obliquity operates in both hemispheres simultaneously (unlike precession). In which case, the albedo rejection of obliquity insolation increases in the NH, combined with the open-sea acceptance of obliquity insolation in the SH, may have led to a small SH temperature increase.
“This has the problem – noted by many – that the warming started in the southern hemisphere.”
Glaciation and deglaciation are not a function of annual average temperature (Greenland Ice accumulation correlates quite positively with temperature). There is a conception of the significance of global average annual temperature because that is what we measure wrt global warming. But this appears to me to be bias of the preconception of AGW.
It is not global annual average temperature but rather regional ( the ice accumulation zone only ), summer time maximum absorbed insolation that matters. The phase change takes place only during the melt-season and only in the glacial zones.
The elevation of the ice sheet, ice albedo, duration required to melt, and perhaps to some extent the dust mentioned here all provide some feedback and make things messy, but I don’t see any contradiction of orbital forcing or requirement to rectify leading SH warming with deglaciation.
The “CO2 problem” is the large change in CO2 concentrations that can’t easily be explained.
If the seas around Greenland are representative, then:
“the annual mean CO2 uptake was positively correlated with the North Atlantic Oscillation Index (NAOI) via wind strength, but was negatively correlated with ΔpCO2 (pCO2air – pCO2sea) and the sea ice coverage.”
Competing factors:
increased sea ice means less uptake ( less air-sea exchange with ice in the way ).
But also, increased wind speeds mean increased uptake from increased mixing and this occurs through Polynyas from katabatic winds even with sea ice as we observed around Antarctica.
So wind may be a key.
This wouldn’t apply like a light switch and would be significant only wrt glaciers by the water. So one would not expect a perfect correlation with total ice mass. Also, some katabatic wind occured as a baseline ( Greenland and Antarctica to this day ).
But it’s not difficult at all to explain the CO2 fluctuations.
Stott and Timmerman (2011) at (https://earth.usc.edu/~stott/stott_papers/Stott%20and%20Timmermann,%202011,%20Chapman.pdf) is one paper. Here are some more links that typically refer to the so-called “huge CO2 burp that ended the last ice age”:
http://phys.org/news/2015-02-carbon-ocean-ice-age.html
http://www.dailymail.co.uk/sciencetech/article-2683361/Giant-CO2-burp-triggered-end-ice-age-100-times-SLOWER-man-climate-change-claim-scientists.html
http://www.scientificamerican.com/article/what-thawed-the-last-ice-age/
http://www.upi.com/Science_News/2016/01/04/Melted-Pleistocene-ice-lid-let-out-a-lot-of-CO2/1441451941912/
https://summitcountyvoice.com/2013/08/15/climate-west-antarctica-meltdown-may-have-been-trigger-for-end-of-the-last-global-ice-age/
and there are more …
Here are some more links that typically refer to the so-called “huge CO2 burp that ended the last ice age”:
Or, of course, the ending of the last ice age that release a lot of CO2.
Donald,
If your comment of October 3, 2016 at 12:24 pm is a reply to my comment: “I’ve never seen that put forward in any of the many papers I’ve read on the ice ages…” then here are a few notes on the links you reference in support:
——————————–
#1: Hypothesized Link Between Glacial/Interglacial Atmospheric CO2 Cycles and Storage/Release of CO2-Rich Fluids From Deep-Sea Sediments, Stott & Timmermann
– this is a paper attempting to explain the changes in CO2 during ice age cycles.
——————————–
#2: The press release from Nature’s marketing dept on the paper: Boron isotope evidence for oceanic CO2 leakage during the last deglaciation, Martinez-Boti et al
– this is a paper attempting to explain the changes in CO2 during ice age cycles.
As the press release states: ‘Co-author Dr Gavin Foster from the University of Southampton comments: “Just like the way the oceans have stored around 30 per cent of humanity’s fossil fuel emissions over the last 100 years or so, our new data confirms that natural variations in atmospheric CO2 between ice ages and warm interglacials are driven largely by changes in the amount of carbon stored in our oceans.’
The press release has similar ideas to the actual paper. For example:
“Atmospheric CO2 fluctuations over glacial-interglacial cycles remain a major challenge to our understanding of the carbon cycle and the climate system. Leading hypotheses put forward to explain glacia-interglacial atmospheric CO2 variations invoke changes in deep-ocean carbon storage (1,2), probably modulated by processes in the Southern Ocean, where much of the deep ocean is ventilated..”
——————————–
#3: This one is the Daily Mail. You are citing newspapers of the inestimable quality of the Daily Mail, citing their review of a science paper. If you cite a paper I will have a look. Anyone citing tabloid reviews of papers at #3 in their list tells me they have only maximum 2 papers they have read.
Still, I press on to your #4..
——————————–
#4: Scientific American reviewing Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation, Skakun et al 2012.
I also review that paper in this article:
https://scienceofdoom.com/2014/01/09/ghosts-of-climates-past-eleven-end-of-the-last-ice-age/
No it doesn’t put forward the hypothesis you suggest. For example, the paper suggests: “These findings, supported by transient simulations with a coupled ocean–atmosphere general circulation model, can explain the lag of CO2 behind Antarctic temperature in the ice-core record and are consistent with an important role for CO2 in driving global climate change over glacial cycles.”
——————————–
I’ll leave it there as #5 is an article about a paper in a random blog, and #6 is an article on “Summit County Citizens Voice” which is not a journal I recognize, meritorious though it probably is.
If you have comments on actual papers I will be interested to review them.
Turbulent Eddie | October 3, 2016 at 12:21 pm:
“But it’s not difficult at all to explain the CO2 fluctuations.”
The role of Southern Ocean processes in orbital and millennial CO2 variations – A synthesis, Hubertus Fischer et al, 2010:
“Despite the importance for climate changes today and in the
past, the glacial/interglacial CO2 changes could not be accounted for
in carbon cycle models until recently.
In recent model experiments, however, it has become possible to quantitatively explain the 100 ppmv glacial/interglacial shift in atmospheric CO2 concentrations by combining the effects of different processes acting on the global carbon cycle, such as sea surface temperature (SST) and salinity changes, gas exchange, ocean circulation, marine biological export production, terrestrial carbon storage, and carbonate compensation in the deep ocean.
Although the total 100 ppmv change can now in principle be accounted for, the contributions of each individual process to the overall change still carry substantial uncertainties that do not allow for a unique solution to the problem. However, all the models agree that changes in the biological or physical carbon fluxes in the Southern Ocean (SO) connected to export production of organic material at the surface and SO circulation changes, together with their carbonate compensation feedback (Broecker and Peng, 1987) in the deep ocean, represent the most important factors influencing atmospheric CO2 on orbital time scales..”
Well, here is a paper explaining the problem and saying “now it can be explained”. People often write papers to explain problems that previously didn’t have a solution. The fact that a paper is written doesn’t mean the problem is now solved, despite the claim. This is a 2010 paper. Perhaps everyone gradually moves to the position that, yes, this problem is now solved. Perhaps not.
You can read papers saying that the 100,000 year ice age cycle has been solved. And you can read 20 other papers saying it has been solved, each with incompatible theories.
My point – this is not a simple problem, or this would not be a 2010 paper saying “the solution is now at hand”.
” but the changes in CO2 concentrations over ice age cycles are currently a mystery.”
Not really. CO2 changes between glacial/interglacial cycles are well accounted for by Henry’s Law ocean uptake/outgassing in response to temperature change. Recall that CO2 change ALWAYS follows temperature change in the ice core data. The ice core data currently drops off at 800 kyr, but the ocean sediment core data for temperature extends back 5 million years. When ice core CO2 data is plotted against ocean sediment core temperature data, the same relationship of utter dependence of CO2 on temperature holds.
https://geosciencebigpicture.files.wordpress.com/2016/01/vostok-co2-vs-d18o.png
There is plenty of reason to wax mystical about ice ages, but the wistfulness is best applied to why the planet should ever leave its default much warmer state and enter a period of glacial/interglacial oscillations in the first place.
It ain’t CO2. There is no correlation between CO2 and temperature at Phanerozoic scale. Isn’t it reasonable to expect that glacial/interglacial phases have at least something to do with whatever caused the overall ice age in the first place?
It wasn’t dust.
If one considers winter as an analogue to glacials, there’s nothing remarkable about the oceanic CO2 uptake.
I am still stumped why wind speed globally increases so dramatically to distribute the dust, is it because of the temperature differentials between regions, may be…
‘The Chinook’
https://en.wikipedia.org/wiki/Chinook_wind
Too simple, I know.
I am not sure that windspeed did increase. The evidence for this from polar ice-core grain size is equivocal. But if the size of the dust source increases 100-fold, why do we need to envoke an increase in dust? Besides, we know for certain that dust loading DID increase significantly towards the end of each glacial period, because this is not only apparent in the ice cores of Antarctica and Greenland, but also in the record from the Loess Plateau in China. The latter contains a complete dust record going back a million years or so, that agrees with the clacial cycle, with increased dust deposition at each glacial maximum.
Correction to the above post:
“But if the size of the dust source increases 100-fold, why do we need to envoke an increase in wind speed?”
R
I am not sure that windspeed did increase.
I ran a radiative model on various glacial/inter-glacial periods using published estimates of land/ocean mask, sea ice, glacial ice, and greenhouse gases.
I used the same atmospheric profile of 2010 ( so the same clouds, temperature, and humidities ) so this has its limits. Never the less, here are the gradients of net radiance from low to high latitudes in the Northern Hemisphere:
https://turbulenteddies.files.wordpress.com/2016/05/gradient_nh.png
The the difference of LGM gradient ( blue ) compared with 2010 ( black ) was strong, but curiously during summer months. I note above:
“In reality, most of the dust associated with glacial erosion is deposited during summer:
The summer gradients were much higher, but not as great as wintertime gradients. However, this was the difference between 0to45 degree and 45to90 degrees. At around 45 degrees, a much steeper gradient appears in the seasonal maximum radiance:
https://turbulenteddies.files.wordpress.com/2016/05/range_cold.png
On this basis, it appears to me that there is some basis for increased jet stream wind speed, mostly in summer.
In addition, of course, katabatic winds are possible because of the presence of ice sheets, as is observable around Antarctica, so it’s reasonable to believe that wind speeds were greater around the ice sheets, significant to the glacial dust distribution.
I think there is need for a lot more thinking and analysis of the state of the entire globe during the LGM: the vegetation, the winds, the dust, the oceans, etc. We do know that dust got to the places in Greenland and Antarctica where ice cores were drilled. We can only roughly estimate dust deposition at the lower flanks of the great ice sheets. There are studies that suggest the sources of the dust at Greenland were mainly in arid regions of Asia such as the Gobi.
I bet dust particles linger in the soft corn snow while the pure water continues on, the top of the ice sheet getting darker and darker as time marches on. At the end of the age six inches of ‘Black Snow’, sits upon what was left of the once mighty glacier… something like that.
McGee suggests that maximum winds in LGM east Asia were in the spring.
Gustiness: The driver of glacial dustiness?
https://www.researchgate.net/publication/222521140_Gustiness_The_driver_of_glacial_dustiness
I would guess that winds at middle latitudes did increase substantially in general during glacial periods for the simple reason that the poles cooled much more than the tropics, thus increasing the pole-ward temperature gradient and associated winds. From what I recall, dust storms (driven by high winds) from middle-latitude deserts like the Gobi tend to occur predominantly in the spring (March-May) and this would also potentially supply fresh dust cover on top of snow/ice for the summer melt season.
I would expect that the atmospheric dust during glacial maximums was very episodic and occurred mainly in intermittent large dust storms associated with high winds from large cyclonic storm systems, much as happens today in the middle latitudes, but with the dust storms being more frequent, larger, and more intense during the glacial maximums. Because of the episodic nature, the dust might not have very significant atmospheric cooling effect by blocking and reflecting sunlight.
Maybe one of these days someone will attempt to run a global weather forecast model for simulated glacial maximum land, ocean, and ice conditions in each season to see what spins up – preferably one that includes dust generation, transport, dispersion, and deposition, like the one run in real-time by the Naval Research Laboratory or the one run by the University of Athens. Much easier said than done.
>>Oz
>>Because of the episodic nature, the dust might
>>not have very significant atmospheric cooling
>>effect by blocking and reflecting sunlight.
That is a good point Oz. Again it suggests that dust-albedo is likely to be dominant over atmospheric dust. Climate is chaotic, not consistent.
And again the effects of atmospheric and surface dust should be calculated regionally, instead of smearing them across the globe. The melting of NH ice sheets is a local and regional event, and not dependent on a smeared w/m2 value that has been transferred down to Argentina.
Dust? It was Global warming wot did it.
Global Warming Weakens Trade Winds
[http://www.livescience.com/729-global-warming-weakens-trade-winds.html]
Unprecedented trade wind strength is shifting global warming to the oceans, but for how much longer?
[https://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/feb/10/unprecedented-trade-winds-global-warming-oceans]
FactCheck: is global warming intensifying cyclones in the Pacific?
[https://theconversation.com/factcheck-is-global-warming-intensifying-cyclones-in-the-pacific-38984]
There. That’s 97% settled.
Should this post have a /sarc tag? I am really not sure.
The idea that CO2 driven global warming modulates ice ages is illogical, as it does not explain the observed glacial periodicity whatsoever. When global CO2 concentrations increased to a maximum, the world cooled. And when global CO2 concentrations decreased to a minimum, the world warmed. That is hardly conclusive evidence that CO2 as a greenhouse gas is driving millennial global temperatures.
And the paper you cite covers just 150 years of data, which is hardly representative of the glacial cycle; and cites a model, which is not data. Conversely, the recent paper by Christy et al argues that there has been no increase in tropospheric warming (and therefore no increase in tropospheric humidity) since the 1970s, which nullifies the trade wind modulation concept. And I see no connection between the proposed trade wind modulation and glacial modulation – perhaps you could elucidate.
https://thsresearch.files.wordpress.com/2016/09/wwww-ths-rr-091716.pdf
And there appears to be no dramatic increase in strong cyclone activity, as that cited link claimed.
http://models.weatherbell.com/tropical/global_major_freq.png
And there has been a fall in total cyclone energy since the 90s (when global warming was supposed to have been greatest), contrary to that same cited claim.
http://models.weatherbell.com/tropical/global_running_ace.png
> The idea that CO2 driven global warming modulates ice ages is illogical, as it does not explain the observed glacial periodicity whatsoever.
The converse would be more interesting to discuss – how the mechanism that modulates ice ages has any bearing on CO2 driven global warming.
In particular, would be the impact of this mechanism on climate sensitivity?
>>In particular, what would be the impact of this
>>mechanism on climate sensitivity?
It is likely to reduce it. Hansen used his ice age global Co2 and global albedo calculations to confirm his value of climate sensitivity. But there is a problem with that. If albedo is calculated regionally rather than globally, as I have done, its effect becomes much stronger. And if dust is added to the equation, albedo becomes an order of magnitude stronger again.
The new dominance of albedo in glacial temperature modulation has the effect of reducing Hansen’s presumed role of Co2. And so if he recalculated the Co2 climate sensitivity based upon these factoirs, he would find the role of Co2 greatly diminished.
Why leave this vital task to Hansen?
>>Why leave this vital task to Hansen?
Because I am no mathematician. A logical and lateral problem solver, yes indeed, but no mathematician.
Ralf
it seems somewhat contradictory to simultaneously claim
whilst acknowledging you are unable to calculate how diminished as you are “no mathematician”
On what grounds do you make your conclusion if you are unable to offer any quantification? Why “greatly” rather than “marginally”, for instance?
VTG, “On what grounds do you make your conclusion if you are unable to offer any quantification? Why “greatly” rather than “marginally”, for instance?”
Let’s see, Hansen placed black carbon as causing 25% of warming since 1880 and there would be much less ice sheet area to impact during that period than during a glacial period. More ice area would imply a greater amount of feedback/amplification, so it looks like you could put dust in the 25% range to possibly 50% range.
How much attribution is provided to dust would depend on how much the estimator is in love with the theory because what amplification is really due to what is easily manipulated. You could say that the majority of the dust was caused by early fire starting experiments and blame everything of man for example.
http://www.scientificamerican.com/article/soot-more-culpable-in-cli/
> It is likely to reduce it.
I don’t see why. In fact, my own lateral thinking leads me to conclude that an increase in natural variability should actually increase sensitivity.
Furthermore, Jim is very likely to find the same if he thinks about it as laterally as I do. A thought experiment should suffice to show it. A wobbling wheel, for instance. Or the MWP.
The contrarian insistence that the MWP was greater and more global may always remain a mystery.
>>On what grounds do you make your conclusion if
>>you are unable to offer any quantification?
Logic, not math. The dust-albedo theory is able to explain the entire glacial cycle, without the need for Co2. Conversely, Co2 does the opposite if what is expected of it – high Co2 results in cooling, while low Co2 results in warming.
All in all, who needs this contrarian Co2 feedback system??
Ralf
Oh dear.
You make an extravagant claim on the impact of a particular mechanism. You then acknowledge that you cannot, even in the most basic way, quantify this impact. Then you resort to assertion (which you term “logic”).
John McCarthy
I think it’s time to leave this conversation. I don’t think there’s any way back from the place you’ve chosen for yourself.
> Logic, not math. The dust-albedo theory is able to explain the entire glacial cycle, without the need for Co2.
I thought the theory was that dust came from CO2, or lack thereof if we stick to explaining glacial terminations. If we extend the theory, we could say that, conversely, the presence of CO2 should imply a lack of dust. Yet China.
Even ancient logics contain quantifiers, by the way.
Ralph,
Riiiiiiight:
https://2.bp.blogspot.com/-TxrmWHFcNe0/V7uM8x2LSfI/AAAAAAAABDs/ZZXmTHofcUkMX4PtKToagrnBjGAA4yOXACLcB/s1600/noaa_world_rawadj_annual_w_logCO2.png
Didn’t someone mention adjustments?
>>Science of Doom
An impressive list of reviews there, highlighting the complete confusion that still exists regarding modulation of the glacial cycle. It must have taken a while to compile.
I imagine that our paper will come into the ‘Theory C Family’ — non-eccentricity orbital variations, with new terrestrial feedbacks.
R
I do understand the dust, but that is not what is important. In warm times there is more rain and snow and less dust. In cold times there is less rain and snow and more dust. The more dust is covered by much less snowfall. It is the lack of rain and snowfall in cold times when there is little ocean effect rain and snow that allows warming that ends ice ages. This is simple stuff, look at ice core data. the ice accumulation in cold, frozen times is not enough to replace the ice that melts every year.
As I read it, the theory is that ice sheets build up over many tens of thousands of years. The resulting low tempertures and low CO2 levels then cause deserts (the plants fail) and hence dust. The dust starts the ice melting, and as the ice melts the dust stays on top thus making the ice keep on melting. If this is correct, then:
1. We should see the dust on top of the ice sheets now, because the ice sheets started melting several thousand years ago.
2. It’s a self-reinforcing process (as the ice melts, surface dust concentration increases, so the ice melts more), But the fastest ice melt was 8-10kyrs ago, and it is slower now.
2. There isn’t anything to stop the process. As the ice melts, albedo reduces, so temperatures rise and melting continues. Once the ice has all gone, albedo is even lower, so there is nothing to start the next glacial period.
3. The assumption behind the ice cores is that all the past is captured in the ice layers. If the ice has been melting like this theory suggests, then much of the past will be missing.
4. If the ice cores are drilled in areas where thre wasn’t any major melying, then there should be visible bands of dust.
This theory – absent further details – feels like the CO2 theory and the ~100kyr cycle in the Al Gore graphs: Something else triggers the major changes, and dust/CO2 then chips in with its own powerful force – which miraculously loses its power when the original influence decides to change direction. Maybe I’m being unduly harsh, and maybe there is merit in the dust theory, but I have difficulty with the mechanics.
Mike – a good summary.
But we will not see dust on the surface of the Greenland ice sheets, as they are mainly drilling on the 3km high summit at 70 degs north, which has never melted. They do so on purpose, to get the maximum record length. The melting and dust concentration would have been most apparent on the lower reaches of the ice sheet (in both altitude and latitude).
The extra factor that initiates the warming process is increased Milankovitch insolation. And yes, it is a runnaway process once it starts, because dust continues to concentrate on the ice sheet surface. However, the dust-albedo theory has a stop-point, which is reached when the majority of ice has melted and albedo reaches a naturial minimum. The world cannot warm any further than this and the interglacial maxes out at a consistent temperature, which is what we see in the ice-core record. So unlike the CO2 theory, the dust-albedo runaway process reaches a natural limit. In fact, CO2 warming is not required by this theory at all, and appears to be a side-show.
The ice deposition during the glacial max IS enough to counter melting, otherwise the ice sheets would not grow, and Greenland would not have a complete ice-layer record of the LGM. The point of the paper is that during times of high NH Milankovitch insolation, the upper layers on the southern flanks of the ice sheets can melt, concentrating past decades and centuries of dust on the surface, which lowers albedo considerably and causes an interglacial. So there is a latent feedback agent already present in the ice sheets, waiting for an insolation maximum. But without a dust era, there is no dust concentration and no albedo reduction, and no increase in absorption, and the interglacial fails. There are several failed Milankovitch maximums in the ice core record – look at the insolation maximum 170 ky ago, which achieved nothing at all.
ralfellis – Thanks for your reply. But I still have some problems with it.
1. Even if the dust is mostly at lower altitudes and latitudes, surely there would be enough dust to be seen in layers in the cores?
2. The Milankovitch higher insolation comes in a different cycle, so is unlikely to be a major contributor to the ~100kyr cycle (which is the one that I assume we are talking about).
3. If the albedo lowers until a temperature plateau is reached, then there is still nothing to start the next glacial. The absence of dust does not seem to be a possible cause, because the ice that it could have been absent on has melted (and you say the high ice sheets are not candidates).
Mike:
>>1. Even if the dust is mostly at lower altitudes and
>>latitudes, dust would be seen in layers in the cores?
The dust IS in the cores, both in Greenland and Antarctica, that is where the data comes from. And the Greenland dust has been isotopically identified as being Gobi dust. I have assumed 3x more dust at lower latitudes, which is probably an underestimate.
.
>>2. The Milankovitch higher insolation comes in a different
>>cycle, so is unlikely to be a major contributor.
Milankovitch (Great Summer) insolation is the main initiator of interglacials, as the graph below demonstrates (my fig 3 in the paper below). The difficult question is why some insolation maximums have no effect. That question was the reason this paper was written, and the paper fully explains why this happens – increased Milankovitch insolation cannot get a grip on the northern ice sheets unless they are contaminated with dust. So the Milankovitch Great Year cycle is impotent, unless it has been preceded by a dust storm era of at least 10 kyr.
Modulation of ice ages via precession and dust-albedo feedbacks.
http://www.sciencedirect.com/science/article/pii/S1674987116300305
.
>>3. If the albedo lowers until a temperature plateau is
>>reached, then there is still nothing to start the next glacial.
That was true, prior to the MPT. But the climate continued to gently cool during the Pleistocene, and a transition point was reached at the MPT where polar ice caps and ice ages became the preferred and dominant climate mode. So now the climate will always default towards an ice age (and a snowball Earth), unless there is another factor to prevent this. That additional factor is a precessional-obliquity maximum, combined with dust and albedo. Reduced albedo is the Achilles heel of an ice-bound world, and in this case the albedo is controlled by dust deposition, which is in turn controlled by Co2 levels getting too low to support plant life.
So there is now an interesting stand-off between the ice-albedo-driven descent into a snowball Earth, and a dust-albedo-driven return to a warmer climate. But do note that CO2 as a greenhouse gas plays little or no part in this drama, because its global influence is orders of magnitude less than the local and regional influence of the albedo fluctuations of the ice sheets. The only role Co2 provides, is the decimation of all (high altitude) plant life on Earth, which supplies the dust to reduce the albedo.
Milankovitch insolation cycle vs temperatures.
http://s1.postimg.org/4tq2e6am7/temps_insolation_Page_1.jpg
I am more inclined with what popes has said. l also believe dust is a result of ice ages not the cause.
>>l also believe dust is a result of ice ages not the cause.
A position that results in more questions than answers. If dust is not invoked for glacial modulation, then why do we see a 90 to 115 ky glacial cycle? Why do some Milankovitch cycles result in no ice volume decrease and no warming whatsoever, while others result in a full interglacial?
R
You don’t get it. YES, dust “IS” the result of Ice Ages. But the result of that result is termination. Dust doesn’t cause Ice Ages. It contributes to terminations.
Terminations do not occur by a gradual lack of replenishment of snow and ice. They occur as rapid, decisive retreat of ice sheets. As you said: “In cold times there is less rain and snow and more dust. The more dust is covered by much less snowfall.” More or less what Ellis and Palmer claim, except that they emphasize the decrease in albedo at the ice sheets.
oceanic cooling –> oceanic CO2 absorption = plant asphyxiation on the Gobi plateau –> new CO2 deserts –> dust generation…
— or —
–> dust generation (volcano, aerolite) –> less sunlight –> oceanic cooling and plants die on the Gobi plateau…
Wagathon. Yes, but if you invoke vulcanism, you also need to explain why terrestrial vulvanism remains in synch with the precession of the equinox (the Milankovitch cycle) – because the glacial cycle appears to be strongly in synch with precession. A precession-vulcanism correlation is not logical, and nor is it supported by the ice-core record. The ice core dust is not volcanic, it is from the Gobi, which is not known for its vulcanism.
You believe then that the period of global cooling after the Roman warming period (the Dark Ages) caused dust that led to warming again (the Medieval Warm Period) but then, there was cooling again (the Little Ice Age), causing dust that led to the latest warming again, after the 18th century?
Wagathon
You believe then that the period of global cooling after the Roman warming period (the Dark Ages) caused dust that led to warming again (the Medieval Warm Period).
______________________________
No. There are cycles within cycles here, not just a single mechanism. I was explaining the 90 – 115 ky ice age cycle. And under this we appear to have a ~1,000 year something cycle and a ~ 60 year oceanic cycle. These smaller influences are superimposed upon the larger long-term glacial cycle, which is why the temperature record looks so chaotic.
And since we are in a low eccentricity era, obliquity is more dominant than precession at present. And because there is little ice left to effect albedo, the Holocene temperature appears to be regulated by obliquity insolation. This is not proven, but it is an interesting correlation nonetheless and worthy of further research. But no research is being done, because of the overriding concentration and certainty about Co2, so the Co2 theory is stifling all other research. And then people wonder why only Co2 climate regulation appears in research papers.
http://www.euanmearns.com/wp-content/uploads/2016/05/Figure-9.png
Although it has been postulated that industrial black carbon ended the Little Ice Age. Perhaps we were headed for an ice age at that time, and the European black carbon deposits halted that slide into cooler conditions. We will never know, if we divert all our resources into investigating Co2.
End of the Little Ice Age in the Alps forced by industrial black carbon
http://www.pnas.org/content/110/38/15216.abstract
Many suspect that Arctic insolation can trigger glacial initiation. And, my understanding is that Milankovitch believes summer insolation at high northern latitudes may drive both glacial and interglacial cycles with the Antarctic lagging Northern Hemisphere climate change by up to 1,000s of years.
>>Wagathon
>>Milankovitch believes summer insolation at high northern
>>latitudes may drive both glacial and interglacial cycles.
But that theory is if no use whatsoever, if you cannot explain why some insolation maxima are completely ignored by the ice sheets and climate. Yes, a Great Winter may precipitate an ice age, but what is the selective process that initiates an interglacial?
The anser is dust-albedo. And the dust only arrives at certain specific times.
So, you propose an alternative to speculation about an interplanetary source of dust being a de-glaciation trigger?
Maurice Ewing and William Donn published papers in the 1950’s and 1960’s that explained the ice ages warm and cold cycles. It snows more when it is warm and there is thawed oceans that produce ocean effect snowfall and ice increases, piles up, advances and it gets cold after. It snows less when it is cold and there are frozen oceans that do not produce ocean effect snowfall and ice depletes and retreats and it gets warmer. Occam would understand this simple stuff.
Simple, but not logical. The interglacial warming process is very rapid, taking place within the 5,000 year length of a Great Summer (a presessional Milankovitch cycle peak). So if the glacial cycle was merely warming and cooling via precession and obliquity we would expect an interglacial every 23 ky, or perhaps every 41 ky. That no longer happens (it did prior to the MPT, but no longer). Since orbital cycles have not changed for millions of years, there must be a terrestrial feedback mechanism that is now interferring with the previous simple warming and cooling process. That mechanism is the large albedo reductions cause by a great ice age, which did not happen prior to the MPT (it is cooler now than before the MPT). And then you need another mechanism that can end an ice age before we end up with a snowball Earth. That new mechanism is dust. The Achilles heel of an ice age world is albedo – lower the albedo and you instantly get an interglacial. How can you lower the albedo of 1/3 of the planet? Dust.
A scientific theory requires some means of validation. To validate your idea, we would need to compare rates of snowfall vs. rates of ablation during Ice Ages, and then show that when the rate of ablation exceeded the rate of snowfall, termination began. Since the rate of ablation is surely tied closely to Milankovitch insolation, one should look for periods when insolation was increasing rapidly. And sure enough, all the terminations occurred when this was the case. The problem is that many periods when insolation was increasing rapidly did not produce terminations. The only ones that did produce terminations were the ones preceded by heavy dust deposition.
ICE ON LAND – POPE’S CLIMATE THEORY – ABSTRACT
Historically, the earth’s temperature and sea level have been regulated within narrow bounds. These narrow bounds changed over the last 50 million years. Data collected on the earth’s temperature demonstrates increase then decrease in cycles that are bounded. The range of these cycles has changed over the 50 million years, but the range remained well bounded within narrow limits while the temperature levels decreased much more. In the 50 million year period, the warmest times were when there was, relatively, less ice on land and the coldest times were when there was, relatively, more ice on land. The Climate Scientists on all sides of this debate do acknowledge this, but most say the more and less ice is a result of warming and cooling. It is really the primary cause of warming and cooling. During the major warm periods and longer cold periods of the most recent 2 million years, the bounds of temperature and ice were further apart. This occurred because the oceans would get high and warm, with much warm thawed ocean water in Polar Regions and it snowed to remove that warm water from the oceans and dump it on land. This was followed by a prolonged cold period because it took a long time to thaw and remove that much ice.
Proxy data, especially the ice core data from Greenland and Antarctica, demonstrate the correlations between temperature and ice accumulation rates (measured), Infrared Radiation (IR), and Albedo (calculated from temperature). IR is the radiation to space that is a function of a constant multiplied by temperature to the fourth power. It is powerful. Albedo is the proportion of the incident light or radiation that is reflected by a surface, in this case that of earth. The data demonstrates some correlation and some lack of correlation between CO2 and temperature. The correlation is understandable because the vapor pressure of any gas that dissolves in water is a strong function of temperature. Open a hot and a cold carbonated soft drink and see the difference. Data demonstrates excellent correlation with ice on earth and temperature. The extent of ice on earth increases when earth gets colder. Scientists on all sides of the debate acknowledge this. The ice advance or retreat on the earth’s surface is labeled as positive feedback. Some climate theorists fear the ice will reach a “tipping point” or point of no return. In 50 million years, there has never been a tipping point from which there was no recovery. The cycle always recovers. The last ten thousand years has demonstrated tighter bounding. This tighter bound is the new normal.
Earth temperature is regulated by something that is abundant, not a trace gas. CO2 has been arbitrarily assigned responsibility for climate change while the much more abundant greenhouse gas, “Water Vapor”, has been ignored. Water, Ice, Water Vapor, Clouds are abundant and that regulates earth temperature. Earth is warmer when there is less ice on earth and earth is colder when there is more ice on earth. That is not a result, as the Climate Scientists always tell us, it is the cause. I repeat this because it is most important.
IR radiation in the tropics does provide most of the cooling of earth. It has a variable thermostat that increases cooling by a constant multiplied by the temperature to the fourth power. That is the most powerful cooling for earth, but it does not have a fixed thermostat.
In the Polar Regions, in the Northern Hemisphere and in the Southern Hemisphere, there are thermostats with fixed set points. The Polar Oceans freeze and thaw at the same temperature and that does turn cooling on and off. The cooling is provided by more snowfall when oceans are thawed and is turned off when the oceans get cold and freeze and cut off the source of moisture. This is the cooling that has thermostats with a fixed set point that explains the amazing stability of earth temperature, and sea level.
Oceans warm, Polar Oceans Thaw, Snowfall increases. Ice is replenished on Antarctica, Greenland and Mountain Glaciers. Ice builds up and spreads out, reflecting more energy, dumping more ice and ice cold water into the oceans and on land until earth cools. Polar oceans freeze and the sun takes away ice every year until earth warms again.
About 2000 years ago, there was a Roman Warm Period and then it got cold. About 1000 years ago, there was a Medieval Warm Period and then it got cold. That was called the Little Ice Age. It is warm now because it is in the warm part of the natural cycle.
It is a natural cycle and we did not cause it.
CO2 just makes green things grow better, while using less water.
They must scare us so they can tax and control us.
“CO2 just makes green things grow better, while using less water.” Let’s not get off on a tangent regarding whether CO2 exerts a warming force. It turns out that Ellis will agree with you and I will disagree. But that is not the subject here, and furthermore, this has been beat to death in 10,000 posting on Judith’s site.
Alexander Pope,
I’ve mentioned more than once that your theory sounds intrinsically sound. Some might argue it is overly simple, but that’s not a falsification of the theory. Still, the dust hypothesis for relatively rapid accent out of glaciations does not invalidate your theory. I see it as complementary.
Chaotic events do influence earth temperature, but the upper and lower bounds of earth temperature have been limited inside the same bounds for ten thousand years in the NH and SH, this bounding is not chaotic. Earth does not get too warm because it will always snow too much, earth does not get too cold because it will always snow too little. The polar oceans freeze and thaw at the same temperature and turn ocean effect snowfall on and off as needed to limit the upper and lower bounds of temperature.
Nice Summary..
Dynamic
popesclimatetheory, I agree that all agree in the feedbacks you cite. The mystery is why the abrupt change of state and the mechanism of the timing. My hunch is the global overturning ocean currents have the role as the switch mechanism. First, one can see the Quaternary Ice Age as being associated with the separating of the Atlantic and Pacific to give demonstration of the influence of interfering with the polar dissipation gradient. There is also evidence that the AMOC had a lower northernmost termination (off Labrador) in the Younger Dryas period of cold. Perhaps the glacial melt is the extra energy needed to keep the conveyor current in its current most excited state. When the interglacial reaches the point of too little glacial melt, either due too little remaining or a cold event, such as super volcanism or cosmic strike, the excited state is lost and the lower circulation loop takes hold, leading to NH cooling and glaciation, complete with positive feedback of rapidly enhanced albedo. This remains further positively reinforced by the lowering of GHG over many hundreds of years. The glacial state is broken by the combination of high M-Cycle insolation for NH summers with decreased albedo from dust buildup combined with precariously high pressures from glacial heights leading to vulnerability to subjugation. The melt at the base from weight just like an ice skater’s weight melts the ice under their skate blade. Collapsing glaciars are powerful enough new energy to re-excite the global conveyor to its northernmost free point and further hastens the subjugation and collapse.
“The mystery is why the abrupt change of state and the mechanism of the timing.” Exactly! And Ellis and Palmer have provided an answer: the combination of high insolation and high levels of deposited dust. That might not be the entire story. Maybe other factors such as ocean currents can be involved. But there is demonstrable evidence for the Ellis/Palmer theory and evidence for other concepts seems more ephemeral.
Dust formation cycle is an effect of climate change not a cause. During glacial cycles wind circulation increases as a result of climate energy balance and air becomes more dusty. Air circulation decreases during interglacial cycles and air is less dusty. Climate change is caused by life on earth (or carbon cycle). That is why other terrestrial planets do not have signs of climate change.
Nabils…. That is the traditional explanation, but the evidence for wind increases at the LGM are equivocal at best. And we know that a simple ‘carbon cycle’ is not the true explanation, because interglacial inception is strictly a NH phenomina. If Milankovitch insolation was just warming the poles of the planet and causing a ‘carbon cycle’ feedback response, then Milankovitch insolation increases in the SH would also effect climate, and yet they do not.
If interglacial inception is a NH phenomina, then the great landmasses of the NH must be key. And likewise the response of the great ice sheets must also be key. And how can we get the ice sheets to respond so quickly to increased high latitude NH insolation? Well, the Achilles heel of an ice age world is albedo – lower the albedo and an interglacial will rapidly follow. And the easiest way to lower albedo over such a large expanse of the planet, is aeolian dust. And we have a good idea that this is correct, because ice sheets never formed in NE Asia, where the dust loading was greatest. Ergo, dust is causal, not consequential.
How is all the running water that must occur as a result dust warming things up, accounted for in the models? Moving water is death to ice.
“That is the traditional explanation, but the evidence for wind increases at the LGM are equivocal at best. And we know that a simple ‘carbon cycle’ is not the true explanation”
Ralfellis,
It is not equivocal. LGM air circulation was 55% greater than now and the carbon cycle is the only mathematical explanation of climate change. It is demonstrated through thermodynamics.
Please see latest published paper and its discussion, http://www.drroyspencer.com/2016/08/simple-experimental-demonstration-that-cool-objects-can-make-warm-objects-warmer-still/#comments
also visit http://www.pacificengineeringpllc.com then go to publication tab. See Tables 1 and 5 of the book global warming calculation and projection. Air circulation is calculated from LGM to 2100.
It is easy to prove that LGM air circulation was 55% greater than today. Icesheets deposit on land, and land has negligible thermal capacity. Surface water evaporation remains constant; however, surface temperature varies. Therefore m2/m1=W1/W2 where m is dry air mass circulation in kg and W is absolute humidity. If the temperature today is 13.7 degree C and at LGM was 5 degrees C then air circulation ratio can be obtained from the psychometric chart at saturation for simplicity. 55% increase in air circulation is substantial and cannot be ignored. It was dusty because of climate change not the other way around. Dust does not change climate, we know this from our daily observations.
I would like to see the paper published so that the larger audience evaluates as well.
>>It is not equivocal. LGM air circulation was 55% greater
>>than now and the carbon cycle is the only mathematical
>>explanation of climate change.
Your evidence is a climate blog? The real evidence is that the grain size of aeolian dust in Antarctic and Arctic ice cores did not increase significantly. But there was an increase in grain size in dust upon the Loess Plateau in China during the LGM. This indicates that there were stronger winds in the Gobi, but not so much in the polar regions, which is to be expected.
However, the vast increase in Gobi dust deposited upon the Loess plateau during the LGM also indicates large new sources of dust. These were the new CO2 deserts, caused by the low concentrations of Co2 during the LGM.
Quote:
The 18,000 14C yr B.P. map shows that steppe and even desert vegetation extended to the modern coast of eastern China at the last glacial maximum, replacing today’s temperate deciduous forest. Tropical forests were banished from China and broadleaved evergreen/warm mixed forest had retreated to tropical latitudes, while taiga extended southwards to ca 43°N.”
Palaeovegetation of China: a pollen data-based synthesis for the mid-Holocene and last glacial maximum.
http://www.bridge.bris.ac.uk/projects/BIOME_6000/SpecialIssue2/BIOME2_downloads/BIOME2_downloads/yu.pdf
See also:
Chinese Loess Plateau vegetation since the Last Glacial Maximum and its implications for vegetation restoration
http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12052/abstract
Simulations of LGM climate of East Asia by regional climate model
http://link.springer.com/article/10.1007/BF02879520
“Dust formation cycle is an effect of climate change not a cause. ”
did it ever occur to you that it might be both?
I thought not. you think your knowledge is certain
Based on math, published papers, and observation I am certain that dust is not a cause of climate.
>>Nabilswean
>>Based on math, published papers, and observation
>>I am certain that dust is not a cause of climate.
But you must admit that it does explain the glacial cycle very well. It is always difficult to change a paradigm or a personal viewpoint, it takes a while for the new information to sink in. It is a slow osmotic process.
Clive Best has a post about this work of Ellis and Palmer with very interesting graphs:
http://clivebest.com/blog/?p=7024
http://clivebest.com/blog/wp-content/uploads/2016/01/Glacial-cycles-1.png
Indeed, and Clive kindly donated his summary graph to the paper.
Modulation of ice ages via precession and dust-ice albedo.
http://www.sciencedirect.com/science/article/pii/S1674987116300305
R
I don’t understand a lot of those graphs presenting ice volume. Dust, albedo and changes in radiative forcing and feedbacks due to exposed ocean are all surface area dependant, not ice volume. Volume and area are not linearly related.
Also figure 4 looks suspiciously like they are using temperature to derive dust, either directly or indirectly. Since apparently they do not clearly explain what they are doing it is neither reproducible nor falsifiable. I give very little effort to trying to interpret the work of authors who play games like that in the literature.
Hand waving accounts with hidden assumptions serve little or no purpose in science.
Also figure 4 looks suspiciously like they are using temperature to derive dust, either directly or indirectly. Since apparently they do not clearly explain what they are doing it is neither reproducible nor falsifiable.
______________________________
Read on. Figs 8 and 9 show that the main driver of dust volume was actually Co2, not temperature. Temperature is the classic explanation for dust because many assume that deserts have to be aridity induced, when in reality the LGM deserts were CO2 deprivation deserts. Sometimes we need a bit of fresh lateral thinking.
In other words, it was low Co2 that caused warming, not high Co2. And while this is a complete inversion of classic thinking, it makes much more sense and can explain much more. A Co2 feedback interglacial is likely to result in runnaway warming, while an albedo feedback interglacial will inevitably result in a maximum temperature (when the majority of ice has dissipated). The dust-ice albedo mechanism explains so much more than the Co2 concept ever did.
The CO2 deficit causing deserts is reasonable. The desert’s dust lowering ice albedo is reasonable too. But this is a negative feedback and we are looking for a mechanism that causes an abrupt change of state. A change of path of a global current like the AMOC is the best candidate to create a switch, I believe.
>>negative feedback
Negative? A negative feedback promotes stability by resisting a change. The dust-albedo and concentration of dust-albedo is strongly positive, promoting a runaway warming event.
A dust layer on ice will promote insolation absorption and therefore warming and melting. This uncovers successive dust layers below. And since the dust tends to stay on the surface, rather than being washed away, this leads to increasing dust levels, continued reducing albedo, and ever increasing absorption and warming. There is nothing negative about this feedback process.
The seasonal melting occurring in a progressive manner (if there is no fresh precipitation) due to concentration of contamination in the ice is a minor short-term scale positive feedback within a long-term negative feedback. The lowered albedo is ultimately a theorized response to lower precipitation caused by less surface water and lower temperature, caused by higher albedo caused by greater ice sheets.
Even if the dust effect were a positive feedback ( which it is definitely not) there is no explanation for the maintenance of a glacial state versus interglacial. There is no switch. This is the same problem GHG suffers from in being a claimed driving factor. It is the reason an external system driver like M-cycle is a better fit. The problem with M-cycle is that is gradual and very weak and so does not explain abrupt change. Besides, there is not a perfect fit. The global conveyor changing latitude to a new circulation path is a change of state to a lower energy stability. Similar to an electron changing from higher to lower state of orbit, a switch is flicked with no stable in-between stable energy state. It fits the pattern.
>>Even if the dust effect were a positive feedback there
>>is no explanation for the maintenance of a glacial state
>>versus interglacial. There is no switch.
Both are most definitely positive feedbacks, and dust is the switch.
Increasing ice sheets during an ice age is a positive albedo feedback. More ice and snow –> greater albedo –> cooler temperatures –> more ice and snow –> greater albedo … until we reach an iceball Earth. That is the ultimate positive feedback, which is self sustaining until we reach a snowball Earth. What is there to stop it?
The Achilles heel of this ice-albedo feedback system is dust, which lowers the albedo. Especially if there is 15,000 years of dusty ice layers in the ice sheets. And now we get warming –> lower albedo and more insolation absorption –> more warming –> lower albedo and more insolation absorption. Until the all ice sheets dissipate. And again this is a positive feedback – it tends to runaway until the ice sheets are gone, and then it stabilizes itself.
In what way are these runaway processes supposed to be ‘negative feedbacks’?
“In what way are these runaway processes supposed to be ‘negative feedbacks’?”
[Cooling =>Increasing ice => higher albedo => more cooling] is a positive feedback process. The reverse of that is the same process. Add to this the GHG positive feedback and there is even more instability. Several cooling triggers exist, including acute increase in volcanic activity or asteroid strike, it is harder to understand the melting trigger. Glacial collapse due to overgrowth is one possible negative feedback, the switching on of a global overturning ocean current would be a positive feedback to the collapse as would the concentration of dust during the melt.
The dust effect is a negative feedback. [Cooling => less CO2 and precipitation => less vegetation => more dust => higher albedo = warming.] Dust simply is a progressive counterweight to the positive feedbacks of GHG and ice enhanced albedo. Unlike the dust effect, which is gradual and progressive, the ocean current change could occur by changing to a stable lower latitude path or higher one, a switch, with the trigger being a critical degree of glacial collapse caused by the increasing stress of gravity combined with increasing NH summer insolation phase of M-cycle.
>>The dust effect is a negative feedback.
>>[Cooling => less CO2 and precipitation => less
>>vegetation => more dust => higher albedo = warming.
I don’t think you understand. The dust causes lower albedo and rapid warming, not higher albedo and cooling. We are talking about dust on ice here, not dust in the atmosphere.
Please read the full paper.
I made an error in stating higher albedo when I meant lower, which does, in fact lead to warming, which in fact is a negative feedback.
Respectfully, I think your error is just in a typo like mine was but I’m happy to give you a face-saving out and the last word if u like.
Here is the plot of dust vs CO2 (fig 9, with dust logarithmic), and as you can see, there is a very close correlation. The question then becomes, is this correlation causal or coincidental? The arguments in the paper suggest they are absolutely causal, because it is Co2 that modulates dust, and it is dust-albedo that modulates ice sheet ablation and melting.
Modulation of ice ages via precession and dust-albedo feedbacks.
http://www.sciencedirect.com/science/article/pii/S1674987116300305
https://s12.postimg.org/65a2d1dj1/dust_and_co2_log.jpg
One has to admit though that a scaled overlay of temperatures and dust would look pretty much the same. It is not possible to decide whether temperature or CO2 did it just by comparing correlations.
It would seem though that for CO2 there is a plausible mechanism that would lead to a greatly accelerated dust response as the threshold drops below 200 ppm, and that is plant starvation. With temperature, I don’t see a plausible mechanism that would cause such a sudden acceleration in response to a drop of another degree degree or two. This is my reason to prefer CO2 as the explanation.
Is there a story in reverse, where fresh snow covers the dust and prevents its albedo change effect? I am inexpert in this, but have mostly read of ice melting exposing dust and lowering albedo. Do both processes have a chance of creating feedbacks? They seem to be candidates for field testing right now. Are there current experiments in adding dust over snow etc?
Thinking logically from a distance, there are many postulated processes on this thread dealing with changes in ice extent or thickness. It is plausible that change, especially sudden change, occurs when not just 2 or 3 factors happen to coincide, but when 10 factors to align just nicely to produce sudden change? Like all of the above?
Geoff,
I lived in Manitoba Canada for about 6 years. In spring we spread black soil dust over the snow on the tennis courts. The snow melted within a few of sunny days instead of a couple of weeks. The Aussies could then proceed to win the Davis Cup every day for the rest of the spring, summer and ‘fall’ :)
The paper on dust-albedo ice age modulation can be downloaded here:
Modulation of ice ages via precessiona nd dust-ice albedo.
http://www.sciencedirect.com/science/article/pii/S1674987116300305
Ralph
if the dust changes happen thousands of years apart from the temp changes, then are they really the cause?
the graphs look interesting until you notice the scale and realize that anything happening within about 10K years will end up with the lines superimposed, so the fact that you see the dust go up (and back down) prior to the amount of ice going down mean that it’s not the cause.
>>if the dust changes happen thousands of years apart
>>from the temp changes, then are they really the cause?
Good question. But the crux of this theory is that dust on its own is insufficient to produce an interglacial, it also requires increasing Milankovitch insolation in the NH. So the dust can remain within the upper layers of the ice sheet, waiting for a suitable increase in NH insolation. Indeed, it is a prerequisite of the theory that the dust does sit and wait, because another important factor is the concentration of dust from previous millennia on the surface, which allows the interglacial to proceed to completion.
We can see this process in action on the following graph, where the dust-peak 270 ky ago failed to produce an interglacial. Why? Well if you look up to the Milankovitch insolation plot at the top, you will see there was a very weak cycle at that time, and there was insufficient insolation to start the process. So the climate waited patiently for 22 ky until the next, stronger Milankovitch cycle provided enough NH insolation to start the melting process. And once the upper layers of the ice sheet have been eliminated, the previous dusty layers below are exposed, the concentration of dust on the surface can begin, the albedo reduces rapidly, insolation absorption increases in proportion, and the interglacial proceeds in almost a runaway fashion.
http://clivebest.com/blog/wp-content/uploads/2016/01/Glacial-cycles-1.png
I was wondering how these models handle Bering Strait opening and closure? That must have a significant influence on North Atlantic/Barents salinity and temperature?
Another factor I’ve wondered about is the vertical movement of continental plates due to ice loads. I’ve never worked out the numbers but I assume the ice fields over Alaska must have some influence over Beringia’s up and down movements over time? Or does Beringia remain steady as the ice comes and goes?
I mention it because increasing ice loads over Alaska ought to raise Beringia a small amount, which when added to sea level changes ought to seesaw the way heat gets moved into the Barents. I have had to work a bit with rock mechanics to understand oil field behavior, so I have a tendency to see where the subject fits in, and maybe it’s not important?
>>I was wondering how these models handle Bering
>>Strait opening and closure?
The Bering Strait only opened some 11 ky ago, at the end of the interglacial melting and warming process. So it would not have been causal in interglacial inception, nor influential in interglacial perpetuation.
Thanks. My mental model would label the opening of the Bering Straight as a cooling factor because it introduces a relatively low salinity water flow into the Arctic. The way I see it the saltier the water the better it sinks allowing the warm water from the south to enter the Barents. But my timing was way off.
Did anybody look for this desert dust in ocean cores? If the Gobi was sending dust clouds towards North America 20,000 years ago this should be seen in fairly shallow cores.
Ralf Ellis’s paper is important. Dust levels are anti-correlated with CO2. If CO2 falls below about 200ppm then photosythnsesis suffers and die back of fauna and Boreal forests occurs leading to high dust deposits. This would have been much higher and more important at the edges of the ice sheets which have long since melted away. The data we use today are based on ice cores only. Enhanced dust enabled rapid melt back, as it does today in the Alps. However, I think it is only when eccentricity is small that the dust albedo feedback alone becomes the critical factor. This is because low eccentricity suppresses precession enhanced great summer maxima. The last interglacial and the Anglian interglacial (430,000 y ago) are examples of this. Whereas the glacial period preceding the Eemian is driven mainly by the strong precession enhanced changes in summer insolation.
http://clivebest.com/blog/wp-content/uploads/2016/01/Details-Eemian.png
Thanks Clive, your continued support is greatly appreciated. Clive hosted this paper on his climate site when it was still in its inception stage, which generated a lot of feedback that honed and improved the arguments in the final paper.
http://clivebest.com/blog/?p=7024
As did Warwick Hughes, many moons ago, when this paper was little more than idea. My thanks to you both for seeing in the original article, a core of a worthy idea. This paper has largely been crowd-reviewed and crowd-improved, while the peer review process itself demonstrated specialisation at the expense of polymath breadth.
http://www.warwickhughes.com/blog/?p=4019
.
>>However, I think it is only when eccentricity is small that
>>dust albedo feedback alone becomes the critical factor.
I think you are wrong there. You will note that even when eccentricity was high, and therefore NH high latitude precessional insolation peaks were high, there were many insolation strong peaks that did not produce an interglacial (see graph below). (Eccentricity was high between 350 ky and 50 ky ago).
But if precessional insolation alone was capable of initiating an interglacial, then we would have had an interglacial every ~22 ky, and we did not.** So perforce there must be another terrestrial feedback factor that resists and assists the effects of a Seasonal Great Summer (a maximum in seasonal precessional insolation). In which case, it appears evident that the dust-albedo feedback mechanism is required for both low eccentricity and high eccentricity eras.
http://s1.postimg.org/4tq2e6am7/temps_insolation_Page_1.jpg
.
** 22 ky is the length of an average seasonal precessional cycle, as opposed to the precessional cycle. The seasonal precessional cycle includes apsidal precession.
Is finer detail possible for the past 40K years? There have been proposals of the land use (dust) changes brought by the different agricultural/industrial revolutions. One was the clearing of forests by slash and burn combined with grazing and overgrazing. Combined with desertification with decreasing CO2, would the results match the theory?
http://wattsupwiththat.files.wordpress.com/2012/10/cp-8-1473-2012.pdf
I am in the camp of this study.
Any theory of terminations must not only explain why terminations occur when they do, but also WHY THEY DON’T OCCUR SOMETIMES DESPITE LARGE INCREASES IN INSOLATION TO HIGH NORTHERN LATITUDES.
(De)glaciation is not a light switch.
First, it takes a …long… time… to melt all the ice.
But consider the effect of elevation.
The higher the top of the ice, the colder the surface temperature.
So for any of the observed orbital variations, ( and ensuing insolation profiles ) there is a hypothetical elevation at which ice would persist ( as it persisted through the Holocene Climatic Optimum over Greenland ). If the ice is very thick ( and high ) summer insolation increases will be less effective. If the ice is not as thick, glacial state can be more sensitive. Then consider that there is a distribution of ice and a shape of the insolation patterns.
It is not remarkable that there is variation of the glacials.
>>Turbulent
>>The higher the top of the ice, the colder the surface…..
Your argument does not withstand logic. So we have a high altitude ice sheet that is so cold, it can withstand several strong insolation maxima with remarkably little melting. But much later, when that same ice sheet is even bigger and higher, it all melts away within the 5,000 years of a Great Summer (an insolation maximum).
So what is the difference here? Why the sudden and rapid melting? The answer is a new feedback agent – dust. And we know that dust only occurs towards the end of glacial cycles. It all fits together, so why the resistance and animosity?
In a recent paper, Ellis and Palmer (2016) proposed that deposition of dust on giant ice sheets, thus reducing their albedo, was a principal factor in the termination of Ice Ages over the past 800 kyrs.
I DO NOT AGREE WITH THIS.
An explanation of why you do not agree would be useful. What, exactly, is wrong with the concept? Which of the graphs is incorrect? Please do explain.
Dust would also be increasing in the atmosphere which would have the opposite effect by not allowing as much solar radiation to reach the surface of the earth where the glaciation is occurring.
This would have a cooling effect.
As the write-up says, most treatments of dust during the LGM only or mainly considered suspended dust which does produce a cooling effect. But suspended dust settles, and when it does, it produces a warming effect. The cooling effect of suspended dust has been estimated by many studies and it is rather small. The thesis of the Ellis/Palmer paper is that deposited dust has a much bigger (warming) effect.
Indeed. Thanks Donald.
Dust-albedo insolation absorption has an effect that is orders of magnitude greater than either atmospheric dust or CO2 feedback effects. And since my calculation of this is contentious, I would appreciate any feedback people may have.
The argument in the paper is that regional insolation absorption in the NH during a glacial maximum is far more important than global effects. After all, it is regional insolation that melts the annual snow in Canada, rather than the ambient temperature in Argentina. And when calculated regionally instead of globally, the effects of dust-albedo on NH ice sheets becomes by far the largest factor. CO2, which is by definition a global feedback agent, pales into insignificance alongside the regional 130 or 180 wm2 increases that dust-ice albedo can provide.
Does this argument stand up to further scrutiny?
Modulation of ice ages via precession and dust-albedo feedbacks.
http://www.sciencedirect.com/science/article/pii/S1674987116300305
Antarctica which has been in an ice age for eternity is a place to look for to see if the dust theory has merits. I have not heard any mention of dust as a factor in Antarctica.
Figure 5 (part C) shows dust levels in the ice core at Antarctica over 800,000 years. It shows sharp spikes immediately p[receding each termination of an Ice Age.
The difference with Antarctica is that there are no surrounding land masses, so the SH ice age ice sheets cannot extend into lower latitudes – as they can in the NH. And Atarctic sea ice is always exposed to the warming waters of the Southern Ocean, and likewise cannot extend very far. So the smaller Antarctic ice sheets cannot influence global albedo and temperatures anything like as much as the vast NH ice sheets.
This is why interglacials only react to Seasonal Great Summers (Milankovitch peaks) in the northern hemisphere. The southern hemisphere also receives Great Summers, which are asynchronous to those in the NH, but these never trigger interglacials and interglacial warming. Why? Because there are no great ice sheets to modulate in the SH.
The glaciations in the S.H. and N.H were synchronous.
>>The glaciations in the S.H. and N.H were synchronous.
And synchonised with NH Great Summer insolation increases, not SH increases. Two reasons why.
a. NH interglacial warming eventually results in global warming, which impacts on both hemispheres.
b. For the only interglacial we can directly compare in both hemispheres, the Holocene, the precessional insolation increase was also coincident with an obliquity insolation increase. Because eccentricity was low at the time, obliquity had a disproportionately large effect. And obliquity insolation increases occur simultaneously in both hemispheres. So on this occasion, the SH and NH were both warmed by obliquity, before the NH received its precessional insolation boost (and dust-albedo feedback).
We envision that it is the dust pent up in the ice sheets that sustains deglaciation. Repeated from the head post:
For glacial termination to go all the way, it seems important that the ice sheets have become saturated, or mostly saturated, with dust from top to bottom. Deposition of fresh dust drops off steeply in the early stages of deglaciation; the continuing melt-off is thus not sustained by fresh dust but must instead be carried by the old dust that is exposed layer by layer by the melt-off itself. Of course, the old dust gets covered by new snow in the winter, but the strong high latitude insolation may be enough to break through this fresh snow cover even without strong fresh dust deposition. (Maybe this is the crucial role of the strong insolation – to break through each year’s fresh snow cover and get back to work on the old dirty ice underneath.)
This was supposed to be an answer to davidelang’s comment above.
Here’s a question:
One of the major factors of long term atmospheric CO2 is weathering of rocks ( calcium carbonate ).
What role did glacial dust play in modulating CO2? Was there enough calcium exposed on the massive ice sheets to remove CO2? And when dust abated, this removal process of CO2 ceased, allowing accumulation?
>>What role did glacial dust play in modulating CO2?
It is Co2 that regulates dust, not vice versa.
The variations in CO2 during the ice age cycle were probably caused by oceanic absorption and outgassing, dependent upon temperature. But it is not within the scope of this paper to determine exactly how and why CO2 follows temperature.
It is enough to know that Co2 does follow temperature, and that when it reaches minimum levels it is highly detrimental to plant life – especially in arid and high altitude locations. And that these regions of plant extinction will cause the emergence of Co2 deserts, resulting in increased dust generation. This process is confirmed by the massive layers of aeolian dust on the Loess Plateau in China, that details all of the recent ice age cycles.
> It is enough to know that Co2 does follow temperature, and that when it reaches minimum levels it is highly detrimental to plant life – especially in arid and high altitude locations.
Enough for what?
It seems more plausible to assume desertification is related to lack of freshwater as more and more of it gets sequestered as ice.
Also, the exposed continental shelves (from sea level decline) are likely sources of dust. Mosher will chastise you for using CO2 as a desertification unicorn.
>>Enough for what?
Enough for this paper. The explanation for why Co2 follows temperature so closely is an entire field of paleoclimatology on its own, and no firm conclusions have been drawn as yet. But the reason why Co2 varies is not important to the conclusions in this paper.
> the reason why Co2 varies is not important to the conclusions in this paper.
Then the last sentence of the article goes beyond the scope of the paper:
It’s hard to reject a variable we don’t account for.
>>Willard
>>Then the last sentence of the article goes
>>beyond the scope of the paper.
Not at all. If a new theory accounts for the entire glacial cycle, it perforce reduces the role of the previously suggested variable(s). Especially when the strength of a previous variable was in part calculated from the glacial cycle itself, which now has another controlling agent entirely.
> If a new theory accounts for the entire glacial cycle, it perforce reduces the role of the previously suggested variable(s).
As DonaldR keeps on repeating, the new theory explains ice age termination. The scope of the postulated mechanism is far from being established. Thoughts experiments seldom suffice.
Also, we should beware of the possibility that the undelimited scope of a theory hides the effect of neglected variables. More so when it amounts to proposing a mechanism.
No amount of lateral thinking will make the relationship between temps and CO2 go away.
>>As DonaldR keeps on repeating, the new
>>theory explains ice age termination.
Itt seems clear from the rapid cooling into an ice age when precessional insolation reduces, that the preferred climate mode is the cold glacial mode. So now we can explain ice age inception, the reason for several insolation maxima having no warming effect (high albedo), and the reason for the terminating insolation maximum having a rapid warming effect (dust and low albedo).
What more is there to explain? We appear to have a comprehensive theory here. And I see no difference between a thought experiment and a model. All people do with models is load them up with their thoughts, and then act all surprised when the model confirms their thoughts. Whoopi-do…..
> What more is there to explain?
Everything other than the modulation and rhythm of ice-ages and interglacials during the late Pleistocene. Everything left unexplained in the peculiar intermittent climate response. The periodicity of the mechanism being posited:
.
Just identifying the periodicity properly would be nice. This requires hypothesis testing, though.
***
> We appear to have a comprehensive theory here.
Too much comprehensiveness is oftentimes a problem.
***
.
> And I see no difference between a thought experiment and a model.
Perhaps because you don’t do maths, Ralph.
You don’t do logic either, but that’ll have to wait.
Another problem with this theory is the glaciers when they start to melt do not do it in an orderly fashion they often times melt then gain ground then melt etc. Why would they advance once they started to melt due to dust accumulation?
This also does not explain the many Pleistocene abrupt climatic changes the most famous being the YD.
>>When they start to melt do not do it in an orderly fashion
>>they often times melt then gain ground then melt etc.
You mean during the ice age era? There were many retreats of the ice sheets during the ice ages, but the majority of these are coincident with new precessional Seasonal Great Summers. Increased NH insolation can obviously provide a small degree of ice sheet melting, whether there is dust contamination or not.
.
>>This also does not explain the many Pleistocene abrupt
>>climatic changes the most famous being the YD.
You mean Dansgaard–Oeschger events? There are many transient D-O warming events in the Greenland record. These remain unexplained, but they all appear to be coincident with forest fire products. (see graphic below.) It is beyond the scope of this paper to speculate on the mechanism for transient D-O events, but if they were the result of forest fires then this is an independent but very effective mechanism for varying the albedo of NH ice sheets.
https://s17.postimg.org/3uj4es3qn/greenland_ice_1.jpg
.
.
As to the Y-D cooling this also remains beyond the scope of this paper. I am intrigued by the possibility that the Y-D could have been the result of a meteorite impact on the Laurentide ice sheet above the Great Lakes. And that this impact spread slush-ball ice-projectiles all across North America, causing the approx 1/2 million Carolina Bay impact craters that litter the center and east of the USA. Although it is vociferously disputed that the Carolina Bays are impact craters the majority of them point towards the Great Lakes, which is prima face evidence that they all originated from a common source. This is an interesting theory that deserves further study, but one that separates the Y-D from the arguments in this paper.
http://www.cintos.org/SaginawManifold/introduction/index.html
https://s10.postimg.org/ag5zwqgih/bays_lidar.jpg
https://s16.postimg.org/tb32l7vmt/bays_lidar2.jpg
https://wattsupwiththat.com/2013/06/02/multiple-intense-abrupt-late-pleisitocene-warming-and-cooling-implications-for-understanding-the-cause-of-global-climate-change/
How does the dust theory ending of glaciation reconcile the above?
Don Easterbrook is right on with all of his conclusions, he presents in the above article.
http://www.eesi.psu.edu/news/archive-2011/alley-richard-heinz-award.shtml
Another school of thought .
I already said that this is an interesting paper that brings to the fore the discussion about the importance of dust in the glacial cycle. That dust is a positive feedback that adds to the melting of the ice sheets is not controversial. The problem is that the claim that dust controls the glacial-interglacial cycle is unsupported by evidence.
As glacial terminations are very fast, just about 5,000 years for temperatures and 10,000 years for ice sheets melting, it is clear that there must be a lot of feedback factors contributing, and we have already talked about some, ice melting, albedo decrease, sea level rise, decrease in snow, CO2 increase, so why claim that dust is the decisive? No good reason for that.
If we examine with detail the data between 150 and 130 kyr ago, we can clearly see that the maximum in dust took place 5,000 years before the glacial maximum (dashed purple line) and 10,000 years before the ice starting melting (solid purple line).
http://i1039.photobucket.com/albums/a475/Knownuthing/Details-Eemianb_zpsxefeo8tg.png
If dust is the decisive factor and can take place at any time thousands of years before the ice starts to melt, then the timing of dust becomes irrelevant and we have another theory that cannot be falsified. Dust can happen at any time and will do its magic when needed. Taking refuge in the argument that dust is decisive only at periods of low eccentricity as Clive does, turns it into an hypothesis for special cases and again can explain one thing and the opposite.
And the dust hypothesis suffers from concentrating too much in the past 500,000 years. Temperatures cold enough to produce very low CO2 and very high dust levels have only happened in the last 450,000 years and 640,000 years ago. Between 450 and 640 kyr and before that, dust levels were not nearly as high, so again we have to recourse to the amount of dust also not being proportional to the effect.
So we end up with an hypothesis where it doesn’t matter how much dust or when it happens, it is still responsible of the glacial cycle.
So in conclusion:
– Is dust a contributing factor to the melting of ice sheets? Most likely it is.
– Is dust an important factor in the melting of ice sheets? We don’t know.
– Is dust an essential factor in the melting of ice sheets? Probably not.
– Is dust the principal factor effecting the melting of ice sheets? Almost certainly it is not.
Javier makes important points in my opinion. I do not think dust can be causal of termination onset although it can contribute to subsequent rapidity of melt. The reason is the known lag between inferred temperature and CO2 in ice cores. That CO2 lag is about 800 years, and is readily explained by Henry’s law and the thermohaline circulation period. The 2012 Shakun paper erasing this lag is a statistical hash, see essay Cause and Effect for details. So warming inferred from Henry’s law started for some reason not having to do with dust. I suspect it may be changing ocean currents triggered by reaching some sea level low at a glacial maximum, causing NH poleward heat transport from the equator. Glaciation onset Milankovitch. Termination onset ocean shift. Melt acceleration CO2 and dust.
The “known lag” between temperatures and CO2 is actually very uncertain. It depends on assumptions about the rate of ice compaction, which causes a delay between the deposition of snow and the entrapment of air bubbles, such that ice dating from t=0 contains air entrapped at t=0+x. The CO2 time lags obtained for different locations (Greenland vs Antarctica) or different time periods differ. I tried to obtain the time lag myself by fitting different data sets and did not obtain a consistent answer. Specific claims by Shakun or others are nothing more than cherry-picking — which seems enough to get you a Nature paper these days.
“The “known lag” between temperatures and CO2 is actually very uncertain. ”
no just ask rud..
he is CERTAIN of the lag..
of course the rest of science says its uncertain, but RUD,, he is certain..
Ask him.. he was in the lab overseeing all the work.
Ask him, he wrote an ebook… settled that science right then and there!!
ebook science… not a whiff of actual data in that ebook or actual methods…
words..
on
a
page.
pixels
on
a
screen
Mosher, you cannot play the ball so play the man (ad homs) out of ignorance. The Cause and Effect essay is extensively footnoted to peer reviewed papers. It starts with Gore’s lag goof in Inconvenient Truth. Then it discusses the lag and its uncertainties in measurement ( foehn closure, diffusion,which ice core, which glacial termination) with a resulting range 1200 years to 400 years, centered ‘ general consensus’ ~800 years. That sets the table. Then the meat diissects several warmunist attempts to make the lag disappear or cast it as much more uncertain than it is, because so inconvenient an objective observation. The most ‘scientific’ but by far worst was Shakun’s ocean paleoproxies. As a Ph.D level econometrician, I did a decomposition of Shakun’s stats to show the gross problems, and then a simple by proxy (from the SI) distribution of onset/cessation of deglaciation to visually show laymen without stats knowledge just how awful the paper truly was. You should take a look at the resulting figure ‘from the lab’ so to speak. When some proxies have deglaciation onset after others have it ceasing, what you have is crummy inconsistent proxies and another junk climate science paper
So much more than just a whiff of actual data and actual methods in the essay. Pity you didn’t read it before commenting, provably displaying how abjectly ignorant you remain on this topic, thereby totally discrediting yourself. Thanks for doing that so incredibly thoroughly for anyone who wants to check for themselves by reading the essay. Have a nice day.
Eschenbach also did a deconstruction of Shakun on the WUWT site. Yes, I know this is not a peer review deconstruction, but I found it well argued and compelling. Was Eschenbach in error here, or did Shakun et al write a real howler of a paper?
https://wattsupwiththat.com/2012/04/06/a-reply-shakun-et-al-dr-munchausen-explains-science-by-proxy/
Ralfellis, I had forgotten about WE’s separate deconstruction, even though used it with a footnote credit in the essay. The paper is a howler. Just awful. Should never have been published.
Rud
‘Mosher, you cannot play the ball so play the man (ad homs) out of ignorance. The Cause and Effect essay is extensively footnoted to peer reviewed papers. ”
wrong.
I am claiming two things.
1. you claim more certainty than there is, or than you DEMONSTRATE
a) if I attacked YOU as a person, that would be an ad hom.
b) I think you are a fine fellow, it is your CLAIMS to certainty
that I have an issue with.
c) when I ad hom you you will know. I will say
c1) Rud is a X, where x is bad
c2) Rud is an X, therefore dont believe him.
2. FOOTNOTES are NOT data !
a) You are trying the same trick that Jones tried with Willis
by directing him to “GHCN”
b) You cannot correct science with mere words and footnotes.
You have ADVERTISED some science but never show
your work
I apologize if you take offense to being asked for data and methods.
It pissed on Mann and Jones, so you are in good company
hint… that might be an ad hom, depending on the thinness of your skin
Mosher, I provided data. Shakun’s own. I provided methods. A simple histogram of every onset and cessation date, per Shakun. Done in Excel. And explained how to read it once created.
You claim I claimed certainty, when I did not. It is certain there is a lag. It is uncertain exactly how much. The reply made specific the peer reviewed uncertainty, and why. Itnis also certain that warmunists tried to exaggerate the uncertainty or eliminate the lag. The sole point of the essay.
Footnotes are data, in the sense that one is deconstructing peer reviewed papers. The deconstruction ‘data’ is what is in the referenced papers, so anyone can check and see whether there has been selection bias or paper misrepresentation by me doing the deconstruction.
You still got nothing, except offense that I called you out and asked others to check that for themselves. You make in this comment an assertion that is not true, and a data claim that is not true in context. First rule of holes: in one and want out, first stop digging.
Now, about BEST eliminating (26? i did not bother to look up footnote 24 to essay When Data Isn’t again) monthly cold records from Station 166900 to warm Amundsen Scott, based on regional expectations when the nearest reference station is McMurdo, thousands of kilometers away and thousands of meters lower on the Antarctic Coast. Want to try justifying that again logically? It upsets you, for sure. But your comebacks so far have been feeble excuses for an obviously suspect procedure, just a simple stark layman’s example, that infests all of BEST.
>>GET IT..
>>if you cant read I suspect that you cant program
Mosher. If you write, spell, and format like a three-year-old, why is it surprising that nobody can understand what you say?
Ralph
Too funny rud.
You provided
Nothing.
Zip.
Zero.
Nada.
The claim here is not that dust alone causes a termination. The claim here is the combination of dust plus sharply rising solar insolation, together provide the trigger to initiate termination. Of course there has to be a time delay. As we said in the original posting:
“For glacial termination to go all the way, it seems important that the ice sheets have become saturated, or mostly saturated, with dust from top to bottom. Deposition of fresh dust drops off steeply in the early stages of deglaciation; the continuing melt-off is thus not sustained by fresh dust but must instead be carried by the old dust that is exposed layer by layer by the melt-off itself. Of course, the old dust gets covered by new snow in the winter, but the strong high latitude insolation may be enough to break through this fresh snow cover even without strong fresh dust deposition. (Maybe this is the crucial role of the strong insolation – to break through each year’s fresh snow cover and get back to work on the old dirty ice underneath.)”
Of course other feedbacks provide the necessary amplification as termination proceeds. But dust plus solar provides the trigger to initiate termination.
Thank you for a very interesting and well researched article, Donald.
“dust plus solar provides the trigger to initiate termination”
You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several.
“You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several.”
Note the stupid pet tricks
1. a BALD assertion that there is not enough evidence, without a
quantified STIPULATION about what would cause Javier to change
his mind. Note, there is NEVER “enough” evidence for the denier
2. Note the appeal to UNICORNS… unnamed and unspecified
“several feedback factors”
3. Note the ASSERTION of impossibility without proof.
4. Note the appeal to MANY unstated “other theories”
https://contrarianmatrix.wordpress.com/lots-of-theories/
NONE of what Javier says here requires ANY THOUGHT.
I can quite literally program a denier bot to spit this type
of stuff out.
it is mechanical, purely mechanical..
Moves from a playbook that you can employ against ALL and ANY science
That is why… it is meaningless and anti science.
Give me a break Mosher !
Have you any idea just what you sound like ?
Stella…
https://en.wikipedia.org/wiki/I,_Mudd
bot till you drop.
Ironically, this stony boast is thrown from within a glass house.
“I can quite literally program a denier bot to spit this type
of stuff out.”
—
Amusing claim. However, I raise you a dime and say: I can program a bot to sound like Steve Mosher. And I can get it done faster.
>>Mosher
>>Moves from a playbook that you can employ
>>against ALL and ANY science.
Do you know how absurd that sounds, Mosh?
This paper is not anti-science, it is pro-science. It came into being because there was a glaring lacuna at the heart of paleoclimatology – the many missing interglacials. Science cannot claim that Milankovitch insolation modulates ice ages, if most of the Milankovitch maxima fail to produce interglacials.
It was the search to bridge that lacuna, to increase the understanding of science, that led to this paper. Or are you implying that additions to our knowledge are destructive and anti-science? Perhaps Newton should have stayed with his research into alchemy and the Giza pyramids, and never branched out into physics…..
Newton: A Dissertation upon the Sacred Cubit of the Jews
http://www.newtonproject.sussex.ac.uk/view/texts/normalized/THEM00276
.
>>I can program a bot to sound like Steve Mosher.
>>And I can get it done faster.
;-)
“Give me a break Mosher !
Have you any idea just what you sound like ?
too funny.
I dunno I bet there are many theories about it.
How can you be fooled by the simplistic skepticism
of..
1. “you didnt convince me,” AS IF JAVIER will ever be convinced.
How can you NOT ask… well what would convince you?
How can you be tricked by the Knee jerk
“well there are many theories”
Look, your brain may have just fallen out of your head.
I dunno, there are many theories about why skeptics are fooled
by the PLAYBOOK..
The playbook goes like this.
Person A
“I think the sun contributes to climate change…….”
Playbook
““You have not provided enough evidence to support that claim. There are several factors and it is not possible to quantify them properly. This is just an hypothesis between several.”
In FACT he posted the same thoughts at your site and you didnt have
the skeptical balls to call him out for his LAZY skepticism
Ralph Ellis.
I AM NOT TALKING ABOUT THE PAPER
HERE IS WHAT I AM COMMENTING ON
“You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several.”
I AM COMMENTING ON
““You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several.””
GET IT..
if you cant read I suspect that you cant program
here RALPH
AGAIN…
THIS COMMENT
“You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several.”
THAT COMMENT I SAY.. is JUST ZERO.
NOTHING.
NADA
ABSOLUTELY MECHANICAL
And you guys cant even see that.
too funny.
So you accept his argument?
“You have not provided enough evidence to support that claim. There are several feedback factors and it is not possible to quantify them properly. This is just an hypothesis between several”
ralph is your work ( I read it, GOOD WORK) is your work
really “just an hypothesis between several?”
or is it a better one?
I think its a better one.
dolt.
Rapps work
is it just a hypothesis among several?
I think not, UNLIKE JAVIER whom I am criticicizing
But you guys see my name and your knees hit your chin.
robots.
Mosher, you still do not grok the first rule of holes. Amazing.
>>GET IT..
>>if you cant read I suspect that you cant program
Mosher. If you write, spell, and format like a three-year-old, why is it surprising that nobody can understand what you say?
Ralph
Steven,
“UNLIKE JAVIER whom I am criticicizing”
Keep trying harder. You are not reaching.
Javier
If we examine with detail the data between 150 and 130 kyr ago, we can clearly see that the maximum in dust took place 5,000 years before the glacial maximum (dashed purple line) and 10,000 years before the ice starting melting (solid purple line).
_____________________________________
You are comparing the wrong variables. Look instead at the Co2 plot. As soon as temperature increases, the Co2 increases. And as soon as Co2 increases the dust flux reduces, because plant-life recovers and the Gobi returns to being a steppe grassland.
The system can then remain in stasis for 5 ky, waiting for sufficient Great Summer insolation increases to trigger melting, dust concentration, and then runaway feedback melting. Which is what appears to have happened in the casenyou highlighted. But if there is insufficient insolation increase, as happened 270 ky ago, the system is quite happy to remain in stasis until the next Great Summer, when hopefully all the players in this climate drama are ready to play their part.
“The system can then remain in stasis for 5 ky”
And for 40 kyr. It is a curious and quite ad hoc way of triggering interglacials the one you are proposing.
On one occasion the climate had to wait 30 ky. That is hardly an ‘ad hoc way of triggering interglacials’. In my view the system as described is quite consistent, given the chaotic nature of climate in general.
“On one occasion the climate had to wait 30 ky. That is hardly an ‘ad hoc way of triggering interglacials’. In my view the system as described is quite consistent, given the chaotic nature of climate in general.”
Your view is not chaotic but deterministic. Sooner or later that dust is going to get that glacial period and finish it.
>>Your view is not chaotic but deterministic. Sooner or
>>later that dust is going to get that glacial period.
Precisely. Or almost precisely. Out of the the chaos that is climate, there is a glimmer of determinism. But this is not complete determinism, only a passing phase. Prior to the MPT none of this mechanism held at all, and I am sure in a million years it will not hold again. This is merely a short window of determinism, in an endless sea of ever changing climate chaos. And yet Gaia does appear to favour stability, over uncontrolable feedbacks.
> Your view is not chaotic but deterministic.
The two concepts are not incompatible:
https://en.m.wikipedia.org/wiki/Chaos_theory
Must be a vocabulary thing.
Javier,
You are showing the Eemian interglacial in your blow-up and yes you’re right – dust was not the primary cause then for ice sheet collapse! Eccentricity was high enough to enable precession to boost Summer insolation at peak obliquity. It is only when all else fails and CO2 levels fall dangerously low that dust albedo becomes critical. This happened 20,000 years ago and it happened 420,000 years ago.
It is simple to understand why. If the earth’s orbit were exactly circular then the precession of the equinoxes would have no effect whatsoever. The distance of the sun to the earth would always be constant. Only changes in the obliquity of the earth’s axis would change summer insolation at the poles. Unfortunately as the earth got colder, obliquity alone became insufficient to end ice-ages about 800,000 years ago. The deepest and longest glaciations always coincide with low eccentricity. Life itself saves the planet from becoming a snowball earth. When CO2 falls below 180 ppm vegetation near the ice sheets withers and dies. This exposes debris and soil to winds which transport vast quantities of dust onto the ice sheets. This accumulates for thousands of years under dry arid conditions waiting for the next obliquity cycle to save the day through albedo feedback.
Clive, I understand what you say and I am quite convinced that things can happen that way because it is consistent, and dust helps melt the icesheets. What I don’t get is this:
“dust albedo becomes critical”
How do you know? There are other factors at play. How do you know which one is the critical?
>>Eccentricity was high enough to enable precession to
>>boost Summer insolation at peak obliquity.
But if that were the case, then why did the strong precessional Great Summer insolation maximums 170 ky and 80 ky ago not result in an interglacial? The theory has to be able to explain all eventuallities.
Ralf,
Two examples where dust did not apparently play a role at high eccentricity is between 620k and 520k years ago and between 250K and 120K years ago.
http://clivebest.com/blog/wp-content/uploads/2016/10/Euan-study-1024×599.png
The 41k obliquity cycle nearly reasserted itself, although admittedly some of these warm spells were half hearted interglacials. ;-)
Where I think you are right is that general cooling over the last 5 million years has led to ever deeper glacial cycles. These now rely on two extra effects to allow Great summer maximum to end ice ages. Firstly a precession boost at maximum eccentricity, and secondly dust-albedo feedback. The second becomes the most important when the 420ky eccentricity cycle is at its minimum – like now.
On a positive note. Global warming may save us from the next glaciation for another 15000 years. Another ice age would end human civilization.
“dust albedo becomes critical”
How do you know? There are other factors at play. How do you know which one is the critical?
No-one ‘knows’. It is simply a hypothesis that seems to work. ScienceofDoom did a long series of posts reviewing many different papers ‘explaining’ glacial cycles and the conclusion was that none of them really gave convincing arguments.
I think this one does at least for the hardest nuts to crack – low eccentricity Milankovitch cycles.
“It is simply a hypothesis that seems to work.”
Well that’s my point, Clive. It is simply a hypothesis based on certain assumptions. If you take those assumptions at face value, like the dust being able to wait under thousands of years of ice and still be a trigger, then it works. But it is not different in that respect to any other hypothesis. Taking the assumptions of the CO2 hypothesis of terminations at face value it also works.
>>Clive
>>Two examples where dust did not apparently play a
>>role at high eccentricity is between 620k and 520k
>>years ago and between 250K and 120K years ago.
Indeed, but this is what I say. These are ‘failed’ interglacials that did not have dust as a feedback, and so they failed. And from these failures we can tentatively calculate the effectiveness of precessional insolation, both with and without dust feedbacks. And a casual glance at the graphs indicates that the dust feedback is at least as potent as a strong precessional insolation maximum.
I did not use the interglacial data from 600 ky ago, as the ice-core layers are so thin at that time that the data is not entirely reliable.
And your NH vs SH precession plot is interesting, as that is what I am doing at present. By cancelling out NH and SH precession, you end up with the residual, which is a pure obliquity insolation plot. And yes, in certain circumstances, obliquity influence can be more significant. And we know this because prior to the MPT, when the ice sheets were very small, it was obliquity that modulated ‘ice ages’ (such that they were) rather than precession.
Cheers,
Ralph
Javier
If dust is the decisive factor and can take place at any time thousands of years before the ice starts to melt, then the timing of dust becomes irrelevant and we have another theory that cannot be falsified.
__________________________________
Not entirely. The interglacial normally takes place at the next Seasonal Great Summer, when NH insolation rises. So it takes place during a dust era that may have lasted for up to 15 kyr. Only twice was the Great Summer insolation insufficient to trigger an interglacial immediately, with the interglacial 270 ky ago being a good example. And then the system waits until the next Great Summer.
But dust will normally stop even during a very weak Great Summer, because the Co2 decimation of plant-life is obviously finely balanced. Any increase in temperature and therefore Co2 will reduce dust levels.
It is a nice language, great summer, dust era, very much like in Game of Thrones. However the magnitude of the effect does not appear to be related to the intensity of the cause:
http://i1039.photobucket.com/albums/a475/Knownuthing/Glacial-cycles-1b_zpsmsfbtdvf.png
Or can dust be saved from one cycle to the next?
>>Javier
What you have here is ‘little precession = little melt’ and ‘big precession = big melt’. It is a combination of precession and dust-albedo feedbacks that melts the ice sheets, not dust-albedo alone. And we have already identified small precessional maxima (like 270 ky ago) that were insufficient to initiate a full interglacial.
.
>>Or can dust be saved from one cycle to the next?
Of course it can. As that graph illustrates, not all the ice was meted in that ‘failed interglacial’, and so some dusty ice layers would have remained. The next interglacial had stronger insolation, and as long as it could melt its way through the more recent ice layers, it would come across the older dusty layers below.
“So we end up with an hypothesis where it doesn’t matter how much dust or when it happens, it is still responsible of the glacial cycle.”
—
Not quite. The proposal is that deglaciation happens when strong Northern hemisphere insolation impinges on ice sheets that have a high dust load, not just at the surface but more or less from top to bottom. Sustained dusty conditions must have prevailed shortly before an insolation peak. Neither factor alone is sufficient. It may be false, but it is not “unfalsifiable.”
michaelpalmeruw, look at the figure above of the situation at 700-600 kyr ago. The dust event took place >25,000 years before the melt. If that doesn’t falsify the hypothesis, then nothing can. The hypothesis stops depending on when the dust happens.
Not sure what the supposed difficulty is with that particular period. Below a modified graph of temperature an CO2 sandwiched between insolation (top) and dust (bottom). Vertical bands indicate strong insolation and dust (cutoffs are indicated by horizontal dashed lines).
http://mike-palmer-server.uwaterloo.ca/_files/composite.png
The 650k BP period fits the sequence of dust followed by insolation quite well. On the other hand, the interglacial of 400k BP looks a bit suspicious.
Does the dirty ice cum Milankovic explain all the observed variation? It probably does not. However, it seems to account for a good part of the variation, and it seems physically plausible.
>>On the other hand, the interglacial of
>>400k BP looks a bit suspicious.
In what way? 400 ky ago was during a low eccentricity era, when precession insolation was reduced and obliquity insolation was more dominant, so the interglacial is likely to have a different profile.
@Ralph – “In what way? 400 ky ago was during a low eccentricity era, when precession insolation was reduced and obliquity insolation was more dominant …”
—
What I meant is that at –400 ky, deglaciation set in when NH insolation was not very high. The preceding dusty era was intense, of course.
I already said that this is an interesting paper that brings to the fore the discussion about the importance of dust in the glacial cycle. That dust is a positive feedback that adds to the melting of the ice sheets is not controversial. The problem is that the claim that dust controls the glacial-interglacial cycle is unsupported by evidence.
As glacial terminations are very fast, at about 5,000 years for temperatures and 10,000 years for ice sheets melting, it is clear that there must be a lot of feedback factors contributing, and we have already talked about some, ice melting, albedo decrease, sea level rise, decrease in snow, CO2 increase, so why claim that dust is the decisive? No good reason for that.
If we examine with detail the data between 150 and 130 kyr ago, we can clearly see that the maximum in dust took place 5,000 years before the glacial maximum (dashed purple line) and 10,000 years before the ice starting melting (solid purple line).
http://i1039.photobucket.com/albums/a475/Knownuthing/Details-Eemianb_zpsxefeo8tg.png
If dust is the decisive factor and can take place at any time thousands of years before the ice starts to melt, then the timing of dust becomes irrelevant and we have another theory that cannot be falsified. Dust can happen at any time and will do its magic when needed. Taking refuge in the argument that dust is decisive only at periods of low eccentricity as Clive does, turns it into an hypothesis for special cases and again can explain one thing and the opposite.
And the dust hypothesis suffers from concentrating too much in the past 500,000 years. Temperatures cold enough to produce very low CO2 and very high dust levels have only happened in the last 450,000 years and 640,000 years ago. Between 450 and 640 kyr and before that, dust levels were not nearly as high, so again we have to resource to the amount of dust also not being important.
So we end up with an hypothesis were it doesn’t matter how much dust or when it happens, it is still responsible of the glacial cycle.
So in conclusion:
– Is dust a contributing factor to the melting of ice sheets? Most likely it is.
– Is dust an important factor in the melting of ice sheets? We don’t know.
– Is dust an essential factor in the melting of ice sheets? Probably not.
– Is dust the principal factor effecting the melting of ice sheets? Almost certainly it is not.
Sorry about the repetition. It seemed to have disappeared in the ether so I sent it again.
If your basic ice sheet was really two miles thick, what would the ice flats weather conditions on top have been like before a pool of melted ice water begins it’s 10,500′ decent to ground level? It sure would have been cool to be alive in those days. Crazy weather…
Arch: I’d really like to hope that someone a lot smarter than me could put together a world-wide description of what conditions were like on the various continents, and especially on and around the ice sheets, with estimates of winds and precipitation, to get a real “feel” for what it was like under those almost unimaginable conditions. In fact that would make a great film. We can propose thermal processes, but it is far too difficult to really understand what was going on in detail.
• Did we say dust is a contributing factor? Yes we did and you agree.
• Is dust an important factor? We think so, along with high insolation. You “don’t know”.
• Is dust an essential factor? We have shown high dust precedes every termination. You think not.
• Is dust the principal factor? We think so along with high insolation. You think certainly not.
• You think the the glacial cycle takes care of everything. The “glacial cycle” produces many spikes in solar insolation but the only ones that lead to termination are the ones preceded by heavy dust layering. The Milankovitch theory simply does not work for terminations.
• As the song goes, “You like tomaytos and I like tomahtos. Lets call the whole thing off.”
“You think the the glacial cycle takes care of everything.”
I don’t think that comment adequately represents my view.
“The “glacial cycle” produces many spikes in solar insolation but the only ones that lead to termination are the ones preceded by heavy dust layering.”
It is not the only common feature. Hypotheses about glacial termination abound. May I remind you for example of:
Paillard, D. 1998. The timing of Pleistocene glaciations from a simple multiple-state climate model. Nature 391 378-381.
“The Milankovitch theory simply does not work for terminations”
I doubt this is a common position. Milankovitch did not stop working all of a sudden during the Mid-Pleistocene. Additional factors are required to produce an interglacial, but they are still happening during the rising phase of obliquity as they have done for the past 3 million years.
Thank You Donald.
there are several types of mania in this debate.
1. the mania that “we dont know”, but C02 cant have ANY effect
or MUST HAVE a small effect
2. the mania that “we dont know, but the Sun explains everything
3. the mania that c02 dunnit all
4. the mania that its all chaotic and we cant understand the finest details
therefore, we know nothing, but it has warmed and cooled over the ages.
Sometimes its as if people act like they are prosecuting a murder and they have to find one suspect.. and there can only be one suspect
Its especially funny when people argue that the climate is super complex and then they proceed to try to find one an only one cause.
Thank you for you intelligent contributions to the discussion, its amazing that we still have to argue about the failings of Milankovitch
Remember Steven, that after all was said and done, Milankovitch, did not ‘dump’ his original data to save ‘space’. He left it to us then, so we could all argue about it now.
“The problem is that the claim that dust controls the glacial-interglacial cycle is unsupported by evidence.”
Straw man
WHO SAID CONTROLS?
nobody but YOU!
Clearly language is your thing.
Substitute controls by triggers:
“the importance of dust deposition as a trigger to initiate terminations of Ice Ages.”
I don’t want to get into an English language discussion with you about if that who triggers is the one who controls or not. But you can keep pointing out all my English mistakes so I improve my English.
Javier,
You may have supplied one of the best responses to Mosher ever.
Mosher,
I don’t disagree with your “mania” comment, except that mania might be too strong a descriptor. More like various folks might have pieces to a puzzle and end up spending time arguing which is the best piece to solve the puzzle, with others maybe saying none of them even belong in the puzzle.
For this discussion I tended to ignore the latter group.
“I don’t want to get into an English language discussion with you about if that who triggers is the one who controls or not. But you can keep pointing out all my English mistakes so I improve my English.”
You are ALREADY in a discussion over terms.
you cant escape discussions about terms.
You claim that they dont supply enough evidence that it is a “trigger”
Lets start with some simple questions.
Suppose there was NO DUST.. do you assert that glacials would still
terminate. yes or no.
IF no, then dust one of several possible “triggers” or “contributing factors”
IF Yes, then on what evidence do you say yes?
Next,
what evidence would you have to see to be convinced that dust may play a triggering role, a causitive role, in terminations?
trigger is a horrible word.. since most guns have ONE trigger,
Digging ever deeper, and still not groking the first rule of holes.
Is dust a contributing factor to the melting of ice sheets? Most likely it is.
How much of a contributor and what is your confidence
– Is dust an important factor in the melting of ice sheets? We don’t know.
you just said it was important above
– Is dust an essential factor in the melting of ice sheets? Probably not.
evidence? confidence?
quantify.
– Is dust the principal factor effecting the melting of ice sheets? Almost certainly it is not.
more settled science from skeptics
The iron hypothesis (a dust driven ice age enhancer) is also concomitant,and may explain inconsistencies with the out of phase southern hemisphere insolation.
http://www.nature.com/nature/journal/v476/n7360/abs/nature10310.html
https://www.princeton.edu/main/news/archive/S39/53/29A19/index.xml?section=topstories
Excellent summary Javier.
I will give this my ‘common man’ reply;
I used to live in a very ice borne area, and I used a wood stove as my heat. My wood stove puffed out black material and this material landed on the surface ice in back of my farm.
Now the question is, did my wood output cause the ice to melt or did the Sun rays upon my black nasty output from my wood stove cause the ice to melt?
I thought about this for awhile and I came to the conclusion it was the Suns rays upon the nasty black stuff my wood stove created that caused the ice to melt. Therefore I had to make the decision if I wanted the ice not to melt I must freeze to death or ignore the melting ice and stay somewhat warm with my wood stove…. I chose the latter because if I were to freeze to death there would no one to conclude that warmth was better than freezing to death.
Did I make my point clear?
Thanks and have a great day and a better tomorrow!!! To everyone!
V. G. Werber
I think you are making an important point. Opening highland roads was an important job before we got the strong machines. When soil or ash was used to melt down to roads over highland with meters of thick snow it was not done in winter time but when the spring came. It needed both sun rays and warming.
Ice Age ending will be triggered by a Milankovic cycle when and only when there is a sufficient height/weight of ice built-up on the N. Canadian planes.
? Please explain. Excessive ice sheet altitude will make its surface colder, and much harder to melt.
Hi
There were 5 or 6 long glacial periods lasting 250+ M years, with 100s of M years interglacials. The current series of ice ages started only some 2.5 – 3 million years ago. This tells us (as you and number of other authors have remarked) that the change in the NH’s insolation during the Milankovic cycles is not sufficient on its own to either cause or end ice ages. So answer must be hidden elsewhere.
Vuk, the short answer to the long view is plate techtonics. Past snowball earth events had very different land ocean configurations. There is a serious theory that the present Pleistocene Ige Age was caused by closure of the Isthmus of Panama, which fundamentally altered ocean circulation. Only thing that does not do is explain the shift from ~41000 cycles from then to about 1mya to ~110000 year cycles to now.
You might also like:
http://www.westcoasttruth.com/the-climate-scandal—the-black-heart-series-by-ralph-ellis.html
Black Heart Series?
Stirred a memory of Dust: His Dark Materials
https://en.m.wikipedia.org/wiki/Dust_(His_Dark_Materials)
Anyway Willard, I sincerely hope this isn’t an attempt to play the man rather than the ball. That wouldn’t do At All.
Were I playing the man, Very Tall, I’d say that Ralph’s work featured in Forbes, and when you make Forbes you’re big in Japan, therefore righter than ALARMISTS!!! may presume:
http://www.forbes.com/sites/realspin/2016/06/30/new-theory-co2-and-climate-linked-but-not-in-the-way-the-consensus-tells-us
Willard,
it’s interesting what one might turn up in the circumstance of attempting to play the man. Not that I’d engage in such despicable behaviour.
Anyway, the bio of the Forbes author reveals
That leads us to
Thence
Which strongly recalls Lewandowsky:
It appears that it’s Lew all the way down at Climate Etc.
Further of interest, that Forbes article appears to have one R. Ellis commenting. R.Ellis offers no objections to the characterisation of their research at Forbes. Interested denizens could speculate if it is the same R Ellis commenting here.
Anyhow, R Ellis over there has his ABC down off pat:
It is a Good Thing everyone is behaving with integrity today.
Willard.
Further of interest, that Forbes article appears to have one R. Ellis commenting. R.Ellis offers no objections to the characterisation of their research at Forbes. Interested denizens could speculate if it is the same R Ellis commenting here.
___________________________________
Yes, I did comment. But in what way was my paper ‘characterised’ in Forbes Magazine? If you suggest that my paper greatly reduces the role of Co2 in global temperature modulation, well, yes, it does precisely that. But that was not the goal of the paper. The goal was to plug the lacuna at the heart of glacial modulation theories, which could not explain why some Milankovitch maxima produced no warming. The reduction in the role of CO2 as a warming feedback was merely a by-product.
And if you suggest that I profit by the ‘Fueling Freedom Project’, well, I would like to see the cheque. Firstly I have never heard of any of these associations. And secondly I did not hear of this article until after it was published (I found it on Google). A cheque would have been nice, since I am now unemployed again. Shell, BP, Texaco, Esso – anyone listening out there??? Gezzz, where are all the bungs, when you could do with one….. ;-)
Ralph,
The “further of interest” is Very Tall’s, not mine.
I already answered your rhetorical question (But in what way was my paper ‘characterised’): look for the emphasized bit in Real Spin’s quote.
Furthermore,
I’m not sure how a paper can reduce the role of CO2, but perhaps it’s just a vocabulary thing. Maybe it’s just a vocabulary thing, and you simply mean is that if your theory is correct, then you can feel justified in minimizing the role CO2. However, that’s not exactly what your paper does, which is to provide a mechanism to take into account ice age termination. In other words, that you extrapolate from that mechanism the usual Anything But Carbon ringtone is just that – an extrapolation.
In any case, I’ll add it to the “lots of theories” page of my Contrarian Matrix:
https://contrarianmatrix.wordpress.com/lots-of-theories/
I’ll even include your name in the Colophon, if you don’t mind.
I also need to add Javier’s “but obliquity.”
Thank you for your concerns.
Hi Ralf,
I’m most flattered to be confused with Willard, but it was me who followed the crumb trail from the Forbes article.
I’m happy to clarify that I was not in any way whatsoever trying to imply pecuniary advantage to you from the article. Although, since you’ve brought up the subject of pecuniary advantage, we can note the interesting fact that it has been claimed by the Texas Observer that the the think tank where the article came from has received north of $3M from Koch related interests.
It is also interesting to note that the article has its genesis in that think tank, which endorses a laissez-faire conception of free-market economics and that Lewandowsky earlier published a claim that endorsement of a laissez-faire conception of free-market economics predicts rejection of climate science, is it not?
Particularly when the article concludes by explicitly rejecting climate science: the current crop of climate models that are rooted in the belief that modern civilization’s use of carbon-based energy is driving our planet inexorably towards extinction. and, inexplicably, you don’t appear to notice this traducing of your peer reviewed science whilst commenting there.
At Climate Etc of course, you’re merely raising points of scientific interest.
Anyway, I hope this doesn’t distract from the evaluation of Dust here.
no willard
try this
http://www.edfu-books.com/
https://www.amazon.com/Jesus-King-Edessa-discovered-historical/dp/1508487618
But there are many theories about Jesus, we just dont know.
https://tomverenna.wordpress.com/2013/03/04/a-new-theory-that-jesus-was-king-of-edessa-not-so-fast-mr-ellis/
> back to the dust
There you go:
http://www.edfu-books.com/news.html
>>Mosher
>>Verenna review
It is so apt that Mosher should cite a book-review by a failed student and religious fundamentalist with an agenda, who did not bother to read the book he was reviewing. A bit like Mosh really.
The bogus book review…
http://www.westcoasttruth.com/the-thomas-verenna-affair-part-one—the-black-heart-series-by-ralph-ellis.html
http://www.westcoasttruth.com/a-vacuous-and-petrified-academia—part-one—the-black-heart-series-by-ralph-ellis.html
Oh, and if you want to argue the points being made in that book, please go ahead. But I warn you that if you have never heard of King Abgarus and King Izas Manu before, and I am certain that you have not, you will be on the back foot all the way.
Ralph.
I’ll have two sugars with my morning braggadocio. Oh, and a side of popcorn. Thank you!
> It is so apt that Mosher should cite a book-review by a failed student and religious fundamentalist with an agenda
Is it, Ralph?
Then I guess it is also apt to note that West Coast Truth has a Staff page:
http://www.westcoasttruth.com/staff.html
Your name doesn’t appear, but if we click on Russell Scott, we get to
http://www.therussellscottshow.com
The DVD titles are intriguing: I leave it to Very Tall to list them.
Your own contribution to the website seems to be the Black Heart Series. Could you describe it for us? I thought it was about climate, but then there is this thing about an Islamic scandal:
http://www.westcoasttruth.com/the-islamic-inventions-scandal—the-black-heart-series-by-ralph-ellis.html
My own guess is that Russell is a friend and lets you blog on whatever you fancy, as long as it’s lateral enough for what his niche.
I am not your slave, W.
After our earlier very brief visit to “westcoasttruth” I did consider drawing parallels between the Black Heart of R. Ellis and the Black Helicopters beloved of troofers but found the Texas Public Policy Foundation more, well, interesting.
However, “westcoasttruth” “Russel Scott Show” DVDs do, once again, recall the ghost of Lewandowsky to the Climate Etc banquet.
Dare one ask R. Ellis’ views of the moon landing?
> I am not your slave, W.
Very well, Very Tall.
Since I am no longer on my tablet, I can copy-paste at my leasure. Here’s the second one, the first one leading to a 404:
http://www.toolsforfreedom.com/Decoding-the-New-World-Order-p/2032.htm
Tools for Freedom. New World Order. Citizen Sovereignty. What’s not to like?
Too funny.
Now he is Newton.!!!!
At least it’s original. Modern day Galileos are two a penny.
VTG, if you won’t mind my asking, just whose slave are you,?
Good questions.
I duly submit that Very Tall is a slave to the scientists that are WRONG:
https://tallbloke.wordpress.com/2015/10/11/albedo-regulation-of-ice-ages-with-no-co2-feedbacks/#comment-108286
The truth is out there.
This is pretty cool:
I love the smell of arguing from incredulity in the morning, especially when it’s mixed with exposing the goals of the multiculturalists.
Arch,
You’re welcome:
https://youtu.be/6kSZVtLFygs
I don’t know Russel Scott, and I have no control over the content of his site. But you knew that anyway, didn’t you?
But that was not your intent, was it. You will not argue the theory, history and facts, because you don’t know the history and facts. But you like to play the playground bully, so you all gather in a ring to try and make fun of the cleverest boy in the school. Because bullies have no hope of devising a cogent argument or repost, they can only feign mockery based upon their own ignorance.
Yes, we have all seen this before. And it is not clever, not professional, not civilised, and most certainly not a method of advancing knowledge, history, theology, or science. But history is littered by those who have fought against advancement.
Try challenging, opposing and arguing the theory.
R
> I don’t know Russel Scott, and I have no control over the content of his site.
While you may not have control over what you don’t write, you hopefully do have control over what you write, and must admit that you wrote a whole series of blog posts on his website.
You must also acknowledge that you did an interview about the Odyssey of the Ark of the Covenant.
You also did an interview with him on The Secret Origins of Jesus Christ.
There’s also this interview of you by him on he Book of Genesis and the Hyksos Egyptian Culture.
Your claim of not knowing Russell Scott looks a bit farfetched, Ralph.
Perhaps it’s a vocabulary thing.
>>Perhaps it’s a vocabulary thing.
It probably is. Would you claim to know someone you have never met? Strange.
> Would you claim to know someone you have never met? Strange.
Claiming not to know someone for who you wrote a series of blog posts and with whom you did for more than an hour of interview is stranger still, Ralph. At best your claim fails to be relevant.
I can’t blame you for trying to remain at an arm’s length from a guy who promotes conspiracy theories. You still have to own the fact that your alternative history is being sold into that market. This is your choice.
Even if you denied knowing Russell Scott for a third time, it would still be your market, Ralph.
The rooster doesn’t crows over the Internet.
>>Claiming not to know someone for who you … did for
>>more than an hour of interview is stranger still.
If a polster stopped you in the streets and asked you a series of questions, would you claim that you knew them? You must have the shallowest of friendships with people. Unbelievably strange.
R
Your powers of extrapolation are as impressive as the alacrity with which you move the goalposts for otters, Ralph. Mind the pea now.
I’d find it hard to say, with a straight face, that I didn’t *know* someone with whom I’d had a series of *scheduled* interviews regardless of whether or not I considered them a personal friend or not.
I begin to understand your angst toward “fundamentalists” … you argue like so many I’ve had the pleasure to have met online. One might even say I knew them as well, despite the fact that even simple words like “we” took on wildly alternative meanings from common usage as the apologia demanded.
more fun
https://tomverenna.wordpress.com/2013/03/06/ralph-ellis-jesus-and-his-myth-of-the-king-jesus-of-edessa/
>>Mosher
>>Verenna review
It is so apt that Mosher should cite a book-review by a failed student and religious fundamentalist with an agenda, who did not bother to read the book he was reviewing. A bit like Mosh really.
The bogus book review…
http://www.westcoasttruth.com/the-thomas-verenna-affair-part-one—the-black-heart-series-by-ralph-ellis.html
http://www.westcoasttruth.com/a-vacuous-and-petrified-academia—part-one—the-black-heart-series-by-ralph-ellis.html
Oh, and if you want to argue the points being made in that book, please go ahead. But I warn you that if you have never heard of King Abgarus and King Izas Manu before, and I am certain that you have not, you will be on the back foot all the way.
Ralph.
And if you think a secular interest in biblical studies is incompatible with an interest in science, then I do hope you say the same about Sir Isaac Newton:
A Dissertation upon the Sacred Cubit of the Jews
http://www.newtonproject.sussex.ac.uk/view/texts/normalized/THEM00276
> if you want to argue the points being made in that book
I’d rather argue the points being made in your review of the review, if you don’t mind, Ralph.
My first question would be how you reconcile your “failed student and religious fundamentalist with an agenda” with your critique of academia, e.g.:
http://www.westcoasttruth.com/the-thomas-verenna-affair-part-one—the-black-heart-series-by-ralph-ellis.html
How may Verenna be both a failed student an an illustration of how academia works these days?
>>How may Verenna be both a failed student an an
>>illustration of how academia works these days?
Because he made out he was a professor, but it transpired at a later date he was just a student. So I wrote to Rutgers Uni and explained how he was unfairly reviewing, denigrating and slandering a number of (secular) religious authors, including myself. And so they threw him out of the university. What comes around goes around.
As to Russel Scott, I don’t know him and I have no control over the content of his site, just as you will have no control over the content of New Scientist or the like. And while it might be nice to only write articles for professional and reputable magazines, they simply will not take new ideas from outside the system. As an outsider, both in profession and viewpoint, you will not get published in the major magazines – period.
The situation is very similar to climate science. If you have an alternate theory, like this dust-albedo theory, don’t expect it to be published by Scientific American or the like. You will be reduced to the lower-rung magazines. And then you will be asked why you are published in such a disreputable magazine, while other retards will find a dubious article in the same magazine and start asking about tin-foil hats.
Yes, unbelievable as it may seem, there are some fools out there who are retarded enough to resort to denigration by association. Probably because they are too ill-educated to understand the subject-matter of the article, book or paper in question. Strange, isn’t it? And these same retards will believe the medatious reviews put out by detractors with a scientific or religious agenda, simply because that misinformation reinforces their perticular prejudice. And they will never bother to check those mendatious reviews, because that is not the point – they want to devise an ad-hominem attack whether it is based upon truth or not.
All of this socio-political Machiavellian manipulation is hardly a way to advance knowledge and science, but human kind can be very tribal and backward, even in the 21st century. As you have probably noticed.
R
https://tomverenna.wordpress.com/2014/03/12/why-i-am-leaving-rutgers-university-after-this-semester/
http://unsettledchristianity.com/ralph-ellis-is-absolutely-right-about-tom-verenna/
https://danielomcclellan.wordpress.com/2013/04/10/on-ralph-ellis/
> Because he made out he was a professor, but it transpired at a later date he was just a student.
I thought he said he was a lecturer. Lecturing does not imply professorship, Ralph. Many students do that.
Maybe it’s a vocabulary thing.
***
Interestingly, the article Mosphit linked is dated 2013-03-06.
One of the last articles at Tom’s is one year later:
https://tomverenna.wordpress.com/2014/03/12/the-con-of-the-century/
Have you stalked for more than a year, Ralph?
What comes around takes more time in your world than in mine.
Pray tell more about bullying.
>>What comes around takes more time
>>in your world than in mine.
>>Pray tell more about bullying.
>>Mosh’s links
Redress is always best when served cold, is it not?
And why do you and Mosh simply believe something on the net, instead of researching? In reality, this small cabal (they all know each other) is similar to many I have met in academia over the years – they like to dish out the dirt, but act all innocent and aggrieved if the fan throws anything back at them.
As to Watts, he is a Christian fundamentalist who holds a masters degree in theological studies and styles himself as a moral crusader, but writes posts like the one below. So tell me – why would anyone seek to use someone like Watts, who is a nasty piece of work at best, as an authority on whether my theological revisions are correct or not? As an Atheist I am independent of Church doctrine, while Watts is quite patently not.
http://oi42.tinypic.com/w0gfg3.jpg
As to McClellan, he is a Mormon fundamentalist, a master of Jewish studies and a doctoral student in theology at Salt Lake City (set your clocks back 200 years). And yet McClellan still believes that the Mormon Book of Abraham is a genuine manuscript written by Abraham when he was in Egypt (as claimed by Joseph Smith).
If you know anything about theology, you will know that the Book of Abraham is actually extracts from the Egyptian Book of the Dead, and nothing to do with Abraham. The translation is a complete forgery by Joseph Smith, and yet it remains a core text within Mormonism, and McClellan will not admit that the translation by Smith is completely bogus. He dissembles, prevaricates and angers, but will not admit his own internalised prejudice and error.
https://en.wikipedia.org/wiki/Critical_appraisal_of_the_Book_of_Abraham
(This Wiki entry is supported by critical research and my own translations.)
So tell me – why would anyone seek to use someone like McClellan, who is deceiving himself let alone others, as an authority on whether my theological revisions are correct or not? As an Atheist I am independent of Church doctrine, while McClellan is quite patently not.
.
And do you not see the clear link here with the recent global warming meme? This theological cabal (and others) have used their academic qualifications and supposed moral authority to quash any other opinions – especially those that openly challenged the Church. While the climate 97% use their academic qualifications, supposed moral authority, and the RICOH laws to similarly quash any other opinions – especially those that openly challenge the Consensus.
It is the same tactic, deployed for the same reasons. The 97% Consensus has as much to lose if their worldview is undermined, as this small theological cabal. Any contrarian information would destroy their worldview, and destroy the academic-institutional edifice that they support and which in turn supports them. And so they cling to the Consensus doctrine even when elements of it become indefensible (like the Book of Abraham or the adjusted temperature datasets).
It is the same response for the same socio-cultural reasons, but this predictable response has nothing to do with the furtherment of enlightenment.
R
> Redress is always best when served cold, is it not?
Better still when as cold as the facts you present.
Your claim that Tom “made out he was a professor” doesn’t look true. Your claim that Tom got thrown out of Rutgers U doesn’t look true either. Your insinuation that you got redress by writing Rutgers U then looks farfetched, Ralph.
All the evidence we have is that for more than a year you stalked a student beyond the Internet because he dared to remind you of simple things like ‘Barabbas’ might very well mean ‘son of the father.’ That doesn’t look like redress at all, Ralph. It looks like vindicativeness.
As for your “cabal” theory, please rest assured that there’s a simpler explanation. It’s called a blogring. You can see one on this website – look at the right column.
So yet again, maybe it’s just a vocabulary thing.
I hope no one minds if I respond to Ralph’s unhinged misrepresentations of me. He states the following in his comments:
“As to McClellan, he is a Mormon fundamentalist, a master of Jewish studies and a doctoral student in theology at Salt Lake City (set your clocks back 200 years). And yet McClellan still believes that the Mormon Book of Abraham is a genuine manuscript written by Abraham when he was in Egypt (as claimed by Joseph Smith).”
To set the record straight, I am not and I have never been a “Mormon fundamentalist” in any sense whatsoever. I am one of the most liberal Mormon Ralph or anyone else will ever meet. I received master’s degrees in Jewish studies and biblical studies from the University of Oxford and from Trinity Western University, respectively, and am writing a doctoral dissertation on the cognitive science of religion and the Hebrew Bible through the University of Exeter. I do not believe that the Book of Abraham is a “genuine manuscript written by Abraham” at all and I never done or said anything that could ever possibly put anyone under the misapprehension that I do.
Ralph Ellis has a very long history of laughable forays into character assassination and personal insult. What he does not have is even the slightest clue whatsoever what he’s talking about.
good grief, i need to check what is going on in this thread! Commenters here should not have to defend themselves in such ways
Do you happen to know why O’, is used as a prefix some 975 times in the KJV?
Arch, if you’re talking about “O” before proper nouns, like names or titles, it’s used to indicate the vocative case. Case-based languages alter the form of nouns in order to show what syntactical function they serve, such as the object of a verb, the subject, etc. English and Hebrew no longer use cases, so we use other ways to indicate those functions, like the order in which the words occur. The vocative case is for second person address, or speaking directly to someone. To distinguish that second person address from a third person address, the KJV translators used “O.” So “O king” is used to indicate “king” is directed at the kind. A more modern way to do this might be something like, “Hey, King.” That marks “king” as second person. It’s “Hey, you, king,” not “king” as in “that one over there.”
That is what Strong’s, says about it too. When I read Scripture, it seems to me to be unnecessary. Unusual, for the Word. I would also like to point out I don’t have the answer, just another question.
Hi, Arch. Yeah, it’s not always necessary. The context often makes the appropriate interpretation pretty clear, but there are places where it is necessary. For instance, in Psalm 45:6, the “O” appears before “God,” letting us know it’s second-person address, but in the next verse, it is omitted, leading us to interpret “God, thy God” as an appositional phrase (“God, namely your God . . .”), when in reality the psalmist is addressing the king with the word “God” (“O God [the king], your God [the God of Israel] has anointed you . . .”).
That is why I said, some… there are many places it is unnecessary. Its use is dissonant to me. Granted in some cases it fits well with the events.
The best part today is that we have the relationship for our evidence.
Daniel O. McClellan,
I certainly don’t. FWIW, it was already clear to me that you’re not a fundamentalist of any stripe and that Ralph doesn’t know when to quit.
Ralph
“And why do you and Mosh simply believe something on the net, instead of researching”
I merely pointed at things.
Why do you assume given my educational background ( but you
dont know all the details) that I had not researched.
Funny story.
In Graduate school one of my directors was a pioneer in creating
concordances using the computer.. first of its kind I think.
But he did have his old school system which was index cards..
http://vintondearing.com/biography/
“Textual analysis: His contributions included breakthrough work on the use of computers to detect the minute differences in biblical texts that indicate their age and order.”
So when people ask me how an English major ( before that math and physics) ended up doing computer stuff
I have to say… Vinton Dearing.
So ya, with 12 years of religious education and time spent with vinton
you learn your way around the key text.
And if your interest is in canon formation and apocraphyl texts, then doing a check on your claims was a bit a fun. too funny
and if coins are an old hobby its even MORE FUN
And if folk etemology is an interest… well can you say JACKPOT
All that said.
There are some people who will take instruction.
There are others who will jnot
So I choose just to POINT. no judgement. lots of fun.
McClellan
I do not believe that the Book of Abraham is a “genuine manuscript written by Abraham” at all and I never done or said anything that could ever possibly put anyone under the misapprehension that I do.
_________________________________
Welcome, McClellan, how nice to see you again. But that is a disingenuous reply isn’t it? Readers should understand that there is a backstory here, because we have had a long discussion on this topic before.
Do you agree that the translation made by Joseph Smith of the so-called Book of Abraham is wholly incorrect? And that these manuscripts are in reality extracts from the so-called Book of the Dead and other common Egyptian manuscripts, and nothing to do with the biblical Abraham.
R
Willard
All the evidence we have is that for more than a year you stalked a student beyond the Internet because he dared to remind you of simple things like ‘Barabbas’ might very well mean ‘son of the father.’ That doesn’t look like redress at all, Ralph. It looks like vindicativeness.
____________________________
Why would I be upset about something I have written myself? (I actually give both possibilities in my books – just as I do with ‘barbarian’.). Ah, but neither Verenna nor yourself have bothered to read the book in question, so you are both spouting from a position of ignorance.
How typical.
R
Perhaps you should link to the long discussion, Ralph, so that those who are interested may read it there, in context, and where it is (hopefully) less OT.
If Ralph has demonstrated anything over the years, it is that he will go to any lengths necessary to avoid acknowledging error, engaging facts, or taking responsibility for his comments.
> Why would I be upset about something I have written myself?
How many red herrings can you fit into a rhetorical question, Ralph?
I was talking about the vindicativeness you’ve shown in stalking Tom, which is corroborated by the relish with which you spoke of “redress” and “what comes around.”
Your claim about Daniel’s fundamentalist looks as bogus as your claims regarding Tom. There’s no amount of backstory that can cover for that level of bogusness. Your “but you haven’t read my book” is irrelevant, your overall excuses are so far weak sauce.
I promised Tom that you’ll back off.
Please stop that crap.
***
But speaking of claims of professorship, you might need to correct that one:
http://www.sciencedirect.com/science/article/pii/S1674987116300305
I don’t think Clive is a professor. This only matters insofar as what you regarding making up stuff holds.
>>Your “but you haven’t read my book” is irrelevant,
>>your overall excuses are so far weak sauce.
Hmm, so ‘your mate’ Tom not actually reading the book he is reviewing is irrelevant, is it? Is that how science papers are reviewed nowadays – by reading the Beano instead of the paper in question?
https://en.wikipedia.org/wiki/The_Beano
And you note that McClellan did not answer the question, or explain his views on the Book of Abraham. I am sure McClellan is the nicest person you could meet, much as he says – but on the topic of his belief system and whether that belief system colours and distorts his view of history, he is as slippery as they come.
McClellan:
“Do you agree that the translation made by Joseph Smith of the so-called Book of Abraham manuscript(s) is wholly or in part incorrect? And that these manuscripts are in reality extracts from the so-called Book of the Dead and other common Egyptian manuscripts, and nothing to do with the biblical Abraham.”
Your response need not take more than two minutes to compose. And since you have made the effort to come to this thread, to denigrate my work once more, I am sure you could also make the effort to compose a couple of sentences in answer.
R
> Hmm, so ‘your mate’ […]
Not my “mate,” Ralph. I simply warned Tom over the tweeter that his stalker was still libeling him.
Welcome to the Internet.
If that makes Tom “my mate,” please tell me more about how you communicate with Russell Scott.
You will also note that you haven’t bothered to check if Clive was a professor.
How typical.
Add that to the list of blunders you’ve made so far on this thread alone. I even started to pay any due diligence to your conspirational crap, Ralph. Rope-a-doping won’t help you here.
Welcome to Climate Club.
Look. You’re new here. You do no need to emulate how Newton treated Hooke. You really should desist.
Ask around.
>>blunders
What blunders, exactly? I have answered every question, and have not been faulted.
As to McClellen being a fundamentalist, he is proving that himself, like he did before. I know he is lurking, because he never gives up if he thinks he can score a point. So McClellan:
McClellan:
“Do you agree that the translation made by Joseph Smith of the so-called Book of Abraham manuscript(s) is wholly or in part incorrect? And that these manuscripts are in reality extracts from the so-called Book of the Dead and other common Egyptian manuscripts, and nothing to do with the biblical Abraham.”
He will not answer, apart from some deflective misinformation, because he knows I can undermine his claimed liberal happy-go-lucky persona. Why is this important? Because the opposition of McClellen and others is not based upon scholarship, it is based upon religio-ideological criticism. A bit like some of the institutional opposition that has arisen to the dust-albedo theory, which is again not based upon realism or logic. A bit like your own opposition.
R
> What blunders, exactly?
Claiming that Tom “made out he was a professor.” Claiming that Tom got thrown out of Rutgers U. Insinuating that you got redress by writing Rutgers U. Claiming that Claiming that Daniel was a fundamentalist.
Claiming that you don’t “know” Russell Scott. Writing in your journal article that Clive was a professor. Insinuating that your crap hasn’t been addressed when I’ve already told that you:
– conflate hypothesis and theory;
– presume that your mechanism reduces sensitivity, which is absurd;
– forgot to to check what happens with a lack of dust, to test for instance if China’s dust is responsible for the actual melting;
– need to accept that the lack of CO2 causing dust doesn’t imply that more CO2 will cause a cooling;
– have yet to explain your mechanism in a way that the periodicity is not ad hoc anymore;
– forget that chaos can be deterministic;
The most obvious blunder is to fail to acknowledge our hostess’ request.
As you say over and over again in the forum thread I linked earlier, come, now. The thread is gone. Everything shall pass.
Thanks for playing,
W
‘O’ you are, so…
“our”
occurs 1165 times in 892 verses in the KJV
Page 1 / 36 exact matches (Gen 1:26 – Gen 42:21)
unusual, no meaning given in Strong’s, strange…but hay that’s show biz.
I was in error, I had not checked the Greek. Fail on my part.
>>Claiming that Tom “made out he was a professor.”
He did. Although why you should be so concerned about Verenna is a mystery. Freinds, perhaps?
>>Claiming that Tom got thrown out of Rutgers U.
Emails from the dean available. Although why you should be so concerned about Verenna is a mystery. Freinds, perhaps?
>>Insinuating that you got redress by writing Rutgers U.
Emails from the dean available. Although why you should be so concerned about Verenna is a mystery. Freinds, perhaps?
>>Claiming that Claiming that Daniel was a fundamentalist.
He is. Although why you should be so concerned about McClellan is a mystery. Freinds, perhaps?
.
As to the dust-albedo paper, it does everything you claim it does not. You, like Verenna, have obviously not read the paper you prentend to critique.
R
I think this may be a Lew Gold Mine, Willard.
much as I dislike Lew’s work…
back to the dust.
so lets see..
we got us some trace dust, and some trace GCR, and we dont need no stinking trace C02..
Plus it hasnt warmed… Palmer said so.
Do not forget the possibility that the Egyptians and Greeks were studying millennial climatology as well as millennial astrology – trying to determine when the next Great Summer or Winter would come.
Willard,
This was the start of a chain of comments that were not scientific and rather nasty.
You now reside permanently in my “Do not read again” file.
Geoff
Thank you for your concerns, Geoff.
You’re into my “pretends to do science but doesn’t really” bin.
More by Pr. Palmer:
https://wattsupwiththat.com/2011/10/24/unadjusted-data-of-long-period-stations-in-giss-show-a-virtually-flat-century-scale-trend/
Gee Willard,
The concept of researchers who may have issues with the quality of work of some other researchers, or with their conclusions doing research of other potential hypothesis is about as anti science as you can get.
Glad you pointed this out to us.
I have no idea what concept you’re referring to, Tim, but in any case you’re wrong – papers never stand alone, even in science.
You’re extrapolating a bit too much for your own good. Do continue if you please.
Could be too much extrapolation on my part.
But you gave so little to work from. Not a criticism. Just an acknowledgement I can’t read your mind.
I did not give you anything to work on my mind states, Tim. They’re none of your concerns anyway. You may or may not appreciate this other editorial by Pr Palmer:
https://wattsupwiththat.com/2016/01/04/failed-claim-right-out-of-the-gate-climate-change-altering-greenland-ice-sheet-accelerating-sea-level-rise/
I rather liked the bold prediction offered in the fall.
Damn tablet. It’s Tony’s editorial, and Pr Palmer makes a guest appearance in the comment section.
I stand autocorrected.
The interplay by Willard and Tall Guy passed over my head. In fact I must admit I have no idea what they are talking about. There seems to be a message therein but it was well hidden. The one thing you can be sure of is that sooner or later, responders to a posting on Judith’s site will Google the authors and try to expose their other activities and commentaries, however irrelevant they may be to the current issue, perhaps with the intent of embarrassing them, or perhaps for other reasons. Furthermore, sooner or later, responders will depart from the subject at hand, whatever that may be in the original posting, and revert back to the same old dreary debate on alarmism vs. denialism. So maybe I should make things clear. In the original paper by Ellis and Palmer there is a strong inference that the authors do not think the level of CO2 affects climate – or if it does, not very much. I personally have taken strong issue with their viewpoint on that topic, but I purposely did not include that subject in my posting because it only obfuscates the main issue here, which is initiation of termination of ice ages by a combination of dust and insolation. While I think Ellis and Palmer are wrong in regard to CO2, I think their idea about terminations has merit.
> In fact I must admit I have no idea what they are talking about.
That’s because we conspired to make no sense, DonaldR.
Glad to see that you finally clarified your position regarding E&P’s conclusions. Since the first author came in the comment thread to defend them, it is hard to understand why you purposefully omitted to present your argument against them.
Why do you think the authors are wrong regarding CO2?
Many thanks!
Donald,
They went over my head as well. But then I’m a short guy, a bit over 5’9″. Unlike Very Tall Guy.
He seems practiced at talking over people’s heads.
Hi Donald,
I can only apologise that I followed the irrelevancies. I did think perhaps R Ellis offering rather different interpretations elsewhere might be of interest, but perhaps denizens are less curious than I realised.
Back to Dust.
> I did think perhaps R Ellis offering rather different interpretations elsewhere might be of interest […]
More so when they complement the actual topic, Very Tall, e.g.:
Out of the three emphasized quotes, the second one is the more interesting. (An answer to the bracketed question: because, scale.)
We also note that Ralph knows the word “Ad Hominem,” which you may find interesting considering his comment on failed students with an agenda.
“More by Pr. Palmer:
https://wattsupwiththat.com/2011/10/24/unadjusted-data-of-long-period-stations-in-giss-show-a-virtually-flat-century-scale-trend/
Pretty much of JOKE analysis.
Notice how NOT A SINGLE SKEPTIC objected to his Infilling
of missing data with the average.
Notice how not a single skeptic objected to him using data that wasnt
collected at the same place and time.
Steve, is that you speaking, or are you test-driving your bot? If it’s the latter, maybe do some fine-tuning on the reading comprehension.
Maybe – but Berkeley Earth ‘Pair wise homogenisation’ algorithm does something not too dissimilar. ‘It assumes that climate change forced by external factors tends to happen regionally rather than locally’ to detect and correct shifts. Yet goes on :
‘Infilling occurs in the USHCN network in two different cases: when the raw data is not available for a station, and when the PHA flags the raw data as too uncertain to homogenize’
“Maybe – but Berkeley Earth ‘Pair wise homogenisation’ algorithm does something not too dissimilar. ‘It assumes that climate change forced by external factors tends to happen regionally rather than locally’ to detect and correct shifts. Yet goes on :
‘Infilling occurs in the USHCN network in two different cases: when the raw data is not available for a station, and when the PHA flags the raw data as too uncertain to homogenize’
WRONG.
1. we dont do pairwise homogenizaion.
2. we dont infill missing data, ever.
3. We dont use USHCN, we use the orginal daily sources
GET THAT..
and most importantly, the answer using only stations that require no adjustment, the answer is with 2% of the fully adjusted number.
Yes, Clive it has warmed.
we did land on the moon
“Steve, is that you speaking, or are you test-driving your bot? If it’s the latter, maybe do some fine-tuning on the reading comprehension.”
your analysis was a joke.
Sorry I hurt your feelings,
maybe I should put trigger warnings on my comments
You are cherry picking your answers. Yes you use the original sources but then use pair wise corrections first before a minimisation technique which sounds sophisticated but essentially gives the same result as Hadcrut4.
I agree it has been warming.
http://clivebest.com/blog/?p=6603
“You are cherry picking your answers. Yes you use the original sources but then use pair wise corrections first before a minimisation technique which sounds sophisticated but essentially gives the same result as Hadcrut4.
WRONG.
#1. Our answers differ from hadcrut4 on a country by country comparison. Hadcrut use NWS adjustments. Every NWS has it ow
unique way of adjusting. In some countries the difference is notable,
in some we are higher in others lower.
#2 WE DONT NOT in ANY WAY WHATSOEVER use a pairwise approach. We actually dont even adjust data.
The steps go like this.
A) an expected value is calculated for an area given the latitude
and elevation and seasonality and average weather noise
( less than 10% of the variance)
B) every station is compared to the expected value.. NOT TO
EACH OTHER. there is no PAIR WISE comparison.
C) based on the error ( expected value – station) a QUALITY
SCORE is assigned to the station, from 0 to 1.
D) The process is repeated until the total error is minimized.
E) then the field is integrated and the global ( or country, or state)
average is computed.
F) note, there is no adjusting or infilling of data values. stations
as a WHOLE recieve a weight
There is no “adjusting” of data series as in other methods.
There is station quality rating.
Now I can of course go through and pick the 15K stations that are
rated 1. They show the same warming ( within 2% or so ) of all the data.
So, where does our “adjusted data” file come from?
ITS A POST PROCESSING STEP….
Its shows you what would have been the case had the station behaved as expected relative to the field.
Well, we dont adjust data series during the process. After we have calculated the average, in fact some time after we actually published
we figured out a way to Output what you might call “adjusted”
data
‘During the Berkeley Earth averaging process we compare each station to other stations in its local neighborhood, which allows us to identify discontinuities and other heterogeneities in the time series from individual weather stations. The averaging process is then designed to automatically compensate for various biases that appear to be present. After the average field is constructed, it is possible to create a set of estimated bias corrections that suggest what the weather station might have reported had apparent biasing events not occurred. This breakpoint-adjusted data set provides a collection of adjusted, homogeneous station data that is recommended for users who want to avoid heterogeneities in station temperature data.:
“4) “Breakpoint Corrected”: Same as “Quality Controlled” except a
post-processing homogenization step has been applied to correct for apparent biasing events affecting the long-term mean or local seasonality. During the
Berkeley Earth averaging process we compare each station to other stations in
its local neighborhood which allows us to identify discontinuities and other
inhomogeneities in the time series for individual weather stations. The
averaging process is then designed to automatically compensate for various
biases that may appear to be present. After the average field is constructed,
it is possible to create a set of estimated bias corrections that suggest what
the weather station might have reported had apparent biasing events not
occurred. This data set is recommended for users who want fully quality
controlled and homogenized station temperature data. This data set is created
as an output of our averaging process, and is not used as an input.
NOT PAIRWISE
NOT PHA
That’s why, our field look different than PHA fields. Different approach ENTIRELY
Thats WHY our answers at the country level look different than CRU.
SO, what QUESTION did we seek an answer to?
Simple. SKEPTICS made a claim that had an impression on Muller.
to wit, skeptics argued that
A) GISS wasnt using all the data
B) the adjustments looked suspect and we should not trust these guys.
Our answer.
Ok, you bitched about losing data in USHCN, we will use the 18000
stations in the US ( not 600 or 1200, but 18K)
Ok, you bitched about nasa and ncdc cheating on adjustments..
and people accused Jones of fiddling his adjustments..
OK, we will build an algorithm that has no green politcs.. it just
reduces error.. data driven.
In short we busted the two skeptical objections about excluding data
and objections about cheating.
And of course clown skeptics come along and want to use few stations cause they didnt like the answer all the data gave
Steven Mosher | October 4, 2016 at 3:46 pm |
1. we don’t do pairwise homogenization.
2. we don’t infill missing data, ever.
3. We don’t use USHCN, we use the original daily sources
–
I don’t think you saying this means what you say, Indigo.
–
3. “We don’t use USHCN”,
Wordgames
You use data that is used to produce USHCN
BEST contains the same data as in USHCN.
“we use the original daily sources”
You mean BEST prefers to use original daily sources, where available * but when not available of course you infill the missing data.
You use substituted figures all the time.
All this is spelt out in BEST
especially the fact that daily data is often not available til the end of the month from many sources
1. we don’t do pairwise homogenization.
ROTFL
you do triple homogenization with a double twist, you just pretend that the data is not homogenized.
You use homogenized data under other names, spliced, mixed,
[“The homogenization of climate data is a process of calibrating old meteorological records, to remove spurious factors which have nothing to do with actual temperature change.” Kevin Cowtan] etc and claim, hand on heart, that therefore it is not “homogenized” in your eyes only.
2. we don’t infill missing data, ever.
Really?
Straight face and all?
we don’t infill missing data, ever.
we don’t infill missing data, ever.
we don’t infill missing data, ever.
Not even true.
no infilling Angech
You can look at the FRICKIN GRAPHS and see that MISSING STATION DATA REMAINS MISSING.
Palmer?
He filled misssing data with averages.
bad palmer
http://www.sciencedirect.com/science/article/pii/S1040618200000604
Along the lines of the article I just sent it is the variability of the sun itself which can push the climate from a glacial mode to an inter- glacial mode when the climate is near the glacial/inter- glacial climatic threshold intersection. It would also explain the abrupt climatic changes which were short lived by violent such as the YD for example.
I dare say the sun has varied by a much greater amount then the .1% which is so often mentioned through out it’s long history.
The MAUNDER MINIMUM alone lends support to this kind of thinking.
The most likely candidate for that climatic variable force that comes to mind is solar variability (because I can think of no other force that can change or reverse in a different trend often enough, and quick enough to account for the historical climatic record.
I think solar variability itself can be the agent which can be a significant player in glacial/inter-glacial cycles, counter climatic trends when taken into consideration with these factors which are , land/ocean arrangements , mean land elevation ,mean magnetic field strength of the earth(magnetic excursions), the mean state of the climate (average global temperature gradient equator to pole), the initial state of the earth’s climate(how close to interglacial-glacial threshold condition it is/ average global temperature) the state of random terrestrial(violent volcanic eruption, or a random atmospheric circulation/oceanic pattern that feeds upon itself possibly) /extra terrestrial events (super-nova in vicinity of earth or a random impact) along with Milankovitch Cycles, and maybe a roll for Lunar Effects, all of which control the big large climatic picture.
What I think happens is land /ocean arrangements, mean land elevation, mean magnetic field strength of the earth, the mean state of the climate, the initial state of the climate, and Milankovitch Cycles, keep the climate of the earth moving in a general trend toward either cooling or warming on a very loose cyclic or semi cyclic beat(1470 years or so) but get consistently interrupted by solar variability and the associated primary and secondary effects associated with this solar variability, and on occasion from random terrestrial/extra terrestrial events, which brings about at times counter trends in the climate of the earth within the overall trend. While at other times when the factors I have mentioned setting the gradual background for the climate trend for either cooling or warming, those being land/ocean arrangements, mean land elevation, mean state of the climate, initial state of the climate, Milankovitch Cycles , then drive the climate of the earth gradually into a cooler/warmer trend(unless interrupted by a random terrestrial or extra terrestrial event in which case it would drive the climate to a different state much more rapidly even if the climate initially was far from the glacial /inter-glacial threshold, or whatever general trend it may have been in ) UNTIL it is near that inter- glacial/glacial threshold or climate intersection at which time allows any solar variability and the associated secondary effects, and or other forcing no matter how SLIGHT at that point to be enough to not only promote a counter trend to the climate, but cascade the climate into an abrupt climatic change. The back ground for the abrupt climatic change being in the making all along until the threshold glacial/inter-glacial intersection for the climate is reached ,which then gives rise to the abrupt climatic changes that occur and possibly feed upon themselves while the climate is around that glacial/inter-glacial threshold resulting in dramatic semi cyclic constant swings in the climate from glacial to inter-glacial while factors allow such an occurrence to take place. Which was the case 20000 years ago to 10000 years ago.
The climatic back ground factors (those factors being previously mentioned) driving the climate gradually toward or away from the climate intersection or threshold of glacial versus interglacial. However when the climate is at the intersection the climate gets wild and abrupt, while once away from that intersection the climate is more stable
As we have mentioned quite a few times, if one examines insolation as the cause of terminations, it is impossible to explain the many times there is high insolation but no termination – that is without dust.
The dust concentration in and on the ice/snow must increase if the snowing decreases, as it must if it becomes dryer.
Furthermore the sea level falls and exposes a lot of former seabed to produce dust.
The theory is plausible and interesting.
So… if the dust theory is a solid non-unicorn climate driver… What does that say about the ending of the LIA coincident with industrial (get it?… inDUSTrial) spewing BC and ammonium sulphate PM all over the Alps, then later Greenland and the Arctic.
The problem with these contaminants is that they are actually killing people (mostly the poor and dark-skinned) now. If only we could say that PM air pollution might kill the tidewater goby 50 years from now, then environmentalists might be interested in applying affordable, existing off the shelf pollution controls on these sources. Perhaps even they would see the benefit of killing coal with fracked gas in an effort to buy time and save millions of human beings from choking on smoke.
>>Horstweb
>>What does that say about the ending of the LIA coincident
>>with industry spewing BC over the Alps.
Funny you should say that:
Painter et al.
End of the Little Ice Age in the Alps forced by industrial black carbon.
http://www.pnas.org/content/110/38/15216.abstract
And there is no evidence that Horstweb was paid to say this by Exxon or Texaco…. ;-)
Donald Rapp
“The claim regarding relative dust deposition in the Great Lakes area vs. Central Greenland depends to some extent upon how one reads the blue colors in Plate 5b of Mahowald et al. (1999). With this assumption, dust loading on the ice sheets might have reached as high as about 25 ppm.”
I am unfamiliar with the Mahowald et al. (1999) paper. The mention of the Great Lakes is always a lure for me to investigate further.
My interpretation of that statement: the dust from the Gobi Desert and elsewhere could be traced by isotope study. That the dust landed on Greenland and the Great Lakes region. If my understanding is correct, then I would expect that the dust found in the Great Lakes would also carry the isotope finger print as Greenland.
For me however, the question is: how much dust? when was it deposited? For the last Ice Age termination I would expect lots and lots of dust on the floor of the Great Lakes as they had been previously scrubbed clean by the advancing glacier.
“When I wore a younger man’s clothes”, I scuba dived in some of the Great Lakes. Lake Superior and Lake Huron floors are remarkably un-interesting, almost featureless, and, heres the part I wanted to get to, very little dust (or muck as wet dust becomes. When the ore carrier Edmund Fitzgerald sank off Whitefish Bay in 500 feet of water during a November storm, a deep diving sub was sent to locate and investigate the freighter. She was found resting on her own bottom, not in a quagmire of muck, rather, on pretty solid rock.
I would have expected, over many thousands of years, the dust would accumulate on these Lakes bottoms to a significant thickness. It didn’t seem so to what I can see.
I probably have some assumptions wrong so I request someone pointing out my errors and point me in the direction to “go fish.”
3Km Max Ice sheet thickness=3,000,000mm * Max Dust concentration of 25-ppm = 3-inches dust
Average 1Km ice sheet at 2ppm average dust = 0.1-inch dust
However, given the sediment loading to the Big Lake they call Gitchigoomie never gives up her dirt when the winds of Holocene blow early. Google does locate where the bodies are buried year ’round. Apparently, the bow plowed through a “sand dune”
http://assets1.csc.com/innovation/downloads/Edmund_Fitzgerald.pdf
https://www.uscg.mil/history/WEBSHIPWRECKS/EdmundFitzgeraldNTSBReport.pdf
horstweb
Thank you for the links.
The worst sea for a boat/ship is a following sea/waves. Unless running before the wind and waves, the stern takes the first hit. If the following seas come aboard and swamp the craft, then all forward rigging and structures go to hell in a hand basket. The surface craft becomes a submarine. Down down down to Davey Jone’s locker.
I can’t explain your observations. But the ice cores taken at Greenland clearly show high dust levels prior to the LGM, and the ice cores at Antarctica show spikes in dust prior to all terminations these past 800,000 years. These data are directly relevant to the issue at hand.
Donald Rapp
Just because my observations don’t make sense, doesn’t mean you are wrong. I just find the circumstances interesting. I find a lot of my observations without answer and interesting.
One thing that does not seem to have been chewed on is that for a dust deposition rate of 6 g/m2-yr, as estimated by Ellis and Palmer (2016) the blocking area of annual dust would be 2.5 m2 per square meter. Thus, the estimated levels of dust on the ice sheets at LGM were enough to make them appear very dusty.
That dust would be buried within about 30 cm of snow.
Settled snow = 300kilos/m3. 30cm = 90 Kilos. 6grams/90kilos = 67-mg/Kg (or ppm).
Horstweb’s arithmetic is better than mine. The deposition rate for 30 ppm (assumed by Ellis and Palmer) would be more like 3 g/m2-yr, not 6 g/m2-yr. But the basic argument remains unchanged. Such an amount of dust would have a blocking area of about 1 m2.
Nice and informative post.
So were many of the comments. But not in the ways intended.
Pingback: Dust on Ice Sheets = End of Glaciation | sunshine hours
Someone mentioned something about lower sea levels contributing to dust….would that dust not be made up of a bit of salt?
I didn’t see salt mentioned anywhere, so there it is. Natural deicer.
“ short answer to the long view is plate techtonics……. Only thing that does not do is explain the shift from ~41000 cycles from then to about 1mya to ~110000 year cycles to now.”
Mr. Istvan, if you are still around
Yes, and tectonics explains transition too, cooler oceans, less evaporation, more time required (110ky instead of 44ky) to build up ice on the cnadian trampoline.
https://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Five_Myr_Climate_Change.svg/1024px-Five_Myr_Climate_Change.svg.png
Dust cannot explain the descent into glacial conditions, nor the increase in amplitude. The following from Lorraine Lisiecki (2010) from whose work your graphic is based.
“Figure 3 comparesthe100-kyrpower
of 18O and eccentricity over the past 5Myr (see the Methods
section and Supplementary Information). During this time the
variance of benthic 18O increases exponentially because of an
increase in the sensitivity of the climate system to orbital forcing”
I am very interested in this “increase in sensitivity”. Presumably this would be just because it got colder. She finds that when the 5 myr series is detrended for this increased sensitivity, 41 and 23 kyr wavelets become significant. This is her take on the the low amplitude variation before the Pleistocene.
The tectonic “Panama Canal” was very restricted for a very long time before the Pleistocene.
https://geosciencebigpicture.files.wordpress.com/2016/09/scotese-mol-10.png
This is the condition 10 million years ago according to Christopher Scotese. The vectors are 10 million year increments of the paleocoordinates for two corners of Colorado. South America has been headed north for an even longer time. It can be seen that North America has been grinding obliquely across this interface for a while.
Hi there
Dust has some contribution, so it does volcanic ash, but neither of two or for that mater insolation increase as per Milankovic (would’n be nice be if it was as simple as that) can explain why the current sequence of ice ages has restarted 2.6 MY, after more than 100MY of interglacial.
Tectonics can explain not only restart, but also, slow slide into and the rapid re-bounce out of ice ages.
Greenland glaciers are not only melted by the summer sun, but by the summer rain as the close second, if not even more so for the non-compacted frozen snow. Summer precipitation (May-October) of about 500mm is mainly rain, while the rest of the year precipitation (snow) amounts to about 300mm.
http://images.climate-data.org/location/132922/climate-graph.png
When the balance is restored and reversed glaciers will start growing. For restart of an ice age, it is not lack of dust and small rise in albedo, or minor fall in insolation that is required, but cooler N. Atlantic summers with less summer evaporation and less rain. Data I looked at, show a direct association of the N. Atlantics SST to the area’s tectonic events.
“Dust cannot explain the descent into glacial conditions, nor the increase in amplitude.” Darned right ! And we never said that it did.
> “Dust cannot explain the descent into glacial conditions, nor the increase in amplitude.” Darned right ! And we never said that it did.
Yet Ralph claims his theory is comprehensive, DonR.
Something’s amiss.
>>Dust cannot explain the descent into glacial conditions,
>>nor the increase in amplitude.
As Don said, we never said that it did. Dust-albedo is an explanation for ice ages post the MPT.
Hi Ralph, I certainly agree that dust is a factor, but what changes about dust at the MPT? Surely there were CO2 deserts and dust at earlier glacial maxima. One must consider the possibility that some factor controls both dust AND glacial maxima.
> Dust-albedo is an explanation for ice ages post the MPT.
Then the mechanism proposed is more a hypothesis than a theory.
No wonder it was called a “proposal.”
Maybe it’s a vocabulary thing.
>>what changes about dust at the MPT? Surely there
>>were CO2 deserts and dust at earlier glacial maxima
It is unlikely that there were Co2 deserts prior to the MPT, because the ice ages were much milder, oceanic temperatures were not so cold, and so Co2 would have not lowered as much.
The pre-MPT era was quite different in many respects. Obliqity dominated instead of precession, ice sheets were smaller, temperatures milder, and so there would not have been any significant dust loading. Thus the wild temperature swings of the post MPT glacial era did not occur.
Since the orbital insolation factor has not changed for millions of years, the difference between the pre- and post-MPT eras HAS to be due terrestrial feedbacks. It is most likely that continued cooling during the Pleistocene era forced the climate past a tipping point, where glacial conditions suddenly became the preferred climate mode. So there was no natural (ie orbitally forced) return to interglacial conditions, and the climate needed an additional feedback mechanism to assist it into an interglacial – DUST.
R
That might explain why Hansen has consistently estimated high climate sensitivity values from his paleoclimate estimates.
I’d suggest, divide his climate sensitivity estimates by 10 and proceed from there. The assumption that “2 C warming is dangerous” provides a precedent for making such assumptions. :)
The other point is that only 58 W/m2 of the 160 W/m2 that hit the earth are lost by radiation.
The CO2 starved deserts that produced the dust went from 38°C max ground/air to say 60°C ground 49°C air.peak temperatures.
A desert has to lose twice as much heat by radiation. That heats the atmosphere a lot. The deserts look like glow plugs on Ceres.
“I’d suggest, divide his climate sensitivity estimates by 10 and proceed from there.”
Arbitrarily divide climate sensitivity by 10? You are worse than Monckton and his arbitrary dividing climate sensitivity by a factor of 3.
-1
Some get it some don’t. You are one of those who don’t.
Just like your beliefs about discount rates and how they are used in the real world for making investment decisions between alternatives.
I gave up on you long ago when you were incapable of addressing a simple question.
Donald Rapp,
Thank you for this paper. It is very interesting and makes a lot of sense. Also thank you for your many informative replies to readers’ comments and questions.
If the dust hypothesis is correct, then it poses a considerable dilemma for the sceptics. Global temperature and ice sheets must be very sensitive to dust. Ellis and Palmer describe a 5C temperature rise and a 120 M sea level rise triggered by a little dust from the Gobi Desert.
If the post 1880 warming is due to dust, not CO2, then we are looking at massive ice melt due to black carbon and other industrial particulates.
How seriously will the sceptic community take Ellis and Palmer(2016) ? If Curry, McIntyre etc take it seriously, they will soon be campaigning to reduce fossil fuel burn before our industrial dust melts the ice sheets.
Entropic,
oh dear. You may have found yet another Climate Etc post backing up the research of Lewandowsky, in this instance the lack of coherence of “sceptic” opinion:
The ‘Alice in Wonderland’ mechanics of the rejection of (climate) science: simulating coherence by conspiracism
Lewandowsky, S., Cook, J. & Lloyd, E. Synthese (2016)
While the proposal here (and mind you it is still only a proposal requiring further corroboration) is that dust is an important factor in INITIATING terminations, the full regalia of feedbacks will operate to help propagate the termination. “if the post 1880 …” – who said that? Not me.
You didn’t say this either, Donald: That might explain why Hansen has consistently estimated high climate sensitivity values from his paleoclimate estimates.
entropicman,
I understood the post to be arguing that dust load is high when the planet is cold (dry, reduced vegetation cover, expanded deserts, many major dust storms as the geological evidence clearly shows was the case). And the dust load is low when the planet is warmer, wetter, greener, increased vegetation cover. We are now in an interglacial period and would be on the long downward slope to the next glacial maximum – if not for our GHG emissions (humans’ wise risk mitigation action).
>>I understood the post to be arguing that dust load is high when
>>the planet is cold (dry, reduced vegetation, expanded deserts.
Actually, dust load is high when Co2 is low (lacking Co2, reduced vegetation, expanded Co2 deserts). That aside, yes, industrial emissions from China may well be preventing the slide into a new ice age.
And on a political note, if green energy increases prices, and encourages industry to move to China and India, who don’t give a flying figg about Co2 and particulate emissions, then western green energy is encouraging global warming, not reducing it.
Yes. Furthermore, the green policies are damaging the economies of the developed countries and therefore of the whole world.
If the dust can terminate a glaciation, would it then also be able to start a glaciation. I mean if the snowfall increases the dust will be covered by new snow. There have to be some balance between start and end.
would that not also depend also upon the rate of dust creation, volcanic activity?
>>If the dust can terminate a glaciation, would it then
>>also be able to start a glaciation.
The whole point of the paper is that there is no dust at glacial inception, and greatly increased dust at the termination. This is why a glacial era is able to commence, because the preferred climate mode at present is glacial, and there is no dust to prevent glacial inception.
However, in regions like NE Asia, which were closer to the Gobi and had much higher dust loading, according to Krinner, ice sheets never formed at all. So yes, dust can prevent an ice age, if there is enough of it.
One centimeter of snow fall overnight will cover the dust and the abedo will be restored. Therefore I don’t buy this theory.
One centimeter of snow fall overnight will cover the dust and the abedo will be restored.
That is very true but you forget that at the pole there is just one day and one night per year. So to collapse the ice sheets over a couple of thousand years you just need more ice melt back in summer than ice gain in winter.
“there is just one day and one night per year”
A cool fact I never thought about.
A small pleasure after reading a contentious discussion about the weather 100,000 years ago.
>>one day and one night per year.
Only a true sage can produce one of those ‘never forgotten truisms’. Thanks, Clive.
And it is clear from the ice core record that a strong insolation maximum can not only melt 1cm, but perhaps the top 500 m – even without dust contamination. Look at the ice volume graph. But what it cannot do is go all the way through to interglacial completion, without the assistance of dust-albedo reductions.
I always thought that it was the Earths tilt that was the major cause of glaciation or de-glaciation. As per TV film by Dr’s H Czerski & K Humble
Oribit: Earths extraordinary journey
Every day I seem to see new theories arise and then bite “the dust” does anyone really know this subject, or is it so “Super wicked” no one does
Like most things, the correct answer is all-of-the-above.
What you always thought is what is widely taught to schoolchildren and is permeated in the academic world as well as the press. Surely the earth’s tilt (and other orbital parameters) are involved. But that is not the whole story.
>>always thought that it was the Earths tilt that was
>>the major cause of glaciation or de-glaciation.
The tilt (obliquity) has an approx 42 ky cycle, while the precession of that tilt has an approx 22 ky rotation. If anything, the interglacial cycle (and the ‘failed interglacials’), agree more closely with precession rather than obliquity. (In the post-MPT era.).
The problem has always been that not all precessional cycles (or obliquity cycles) cause interglacials or even failed interglacials. Since the orbital cycles have not changed for millions of years, the reason for this selective response to orbital insolation changed MUST be due to a terrestrial feedback mechanism. But nobody knew what that mechanism was.
The true answer is low Co2 causing dust, and dust causing lower albedo.
R
Ellis and I don’t quite see it the same way. Rather than “the true answer”, I perceive this proposal as an interesting possibility to be taken seriously, but req
requiring a good amount of further study. sorry for interruption!
Too funny.
http://ufodigest.com/article/jesus-king-edessa
http://www.orthodoxchristianity.net/forum/index.php/topic,30138.msg1088308.html#msg1088308
Steven Mosher,
You are behaving like a religious zealot – trying to defend your beliefs in the face of mounting evidence showing they are deeply flawed.
You are adopting the practices of a denier.
Sorry peter
A) I think Ellis has an intersting idea about dust
B) I think Palmer has an interesting idea
C) I think Rapp did a fair job of summarizing.
And then of course I attacked Javier for using stupid skeptical tricks on their work, and they attacked me? when I quoted Javier?
Too funny, even you should get the joke..
OK,
But your frequent use of “too funny” is silly.
Is it “too funny” that you continually dodge dealing with the issue that the Alarmists’ position is denial of the relevant facts – i.e. there argument that GHG emissions are dangerous or doing more harm than good (or will do more harm than good) is unsupported by relevant empirical data?
The Alarmists argument is based on belief and innuendo that GHG emissions are dangerous (or will do more harm than good). You support that argument. Your argument that we can now move forward to make policy to avoid 2 C warming because politicians have accepted the alarmists arguments 2C is dangerous is “too funny”, IMO!!
Scene: Laurel and Hardy are walking down a street with an empty manhole cover. Sooner or later one of them will fall into it. Fast Forward: Scene: Discussion of role of dust in ice age terminations. Sooner or later discussion will revert back to alarmists and deniers. THE INEVITABLE MUST HAPPEN!
>>Too funny….
What is funny, Mosh? Look, I know that many things are funny to little children, but what exactly do you disagree with? If you believe that JC was an AD 30s character, as per classical theology, then why did he:
a. Describe the siege of Jerusalem in AD 70?
b. Lament the death of Zacharias Baruch (Barachias) in AD 68?
c. Lampoon Ben Zizit Hakeseth, who was a leader of the Revolt in the late AD 60s?
d. Get accused in the Talmud of being the leader of the Jewish Revolt in AD 68?
And if you do not know about these millennial conundrums and cannot answer them, then why are you making yourself look foolish by mentioning then at all? Come on, Mosh, what is your answer to these millennial questions? What, exactly, do you think I have said that is wrong. Spell it out, sonny boy.
R
Since this is obscure theology, you will start accusing me of inventing historical characters to suit my arguments. Here is Ben Zizith Hakeseth, a vain and inordinately wealthy aristocratic leader of the Jewish Revolt of AD 68 – 70, as similarly lampooned by JC.
http://www.come-and-hear.com/gittin/gittin_56.html
And you might also explain why JC was jailed alongside revolutionaries who had committed murder in the Revolt. (Mk 15:7) Which (Jewish) Revolt was this, exactly? Are you beginning to understand?
R
> Since this is obscure theology, you will start accusing me
Arguing by prolepsis is easy, Ralph.
Next you’ll argue that your story is a model just like the GCMs, which will compel us to turn to another vocabulary thing.
Ashes to ashes and dust to dust. Sic transit flimsy climate theories.
Need I say more…
http://www.cnsnews.com/news/article/lauretta-brown/pew-most-americans-dont-believe-scientific-consensus-climate-change
wink, wink, nudge, nudge. need I say more, Steven?
I think u better talk to Ralph abut jesus
The failure of “science” in general and “climate science” in particular to police itself sort of disgusts me.
Until only good science reaches the journals and all valid studies are published (hostile peer review and no gatekeeping) science studies will just be fodder for water cooler discussions and nothing more.
Studies that are a basis for policy decisions should have to be 5 sigma and face hostile review.
Steven, we already know you must have talked with the stars,…
http://thehill.com/blogs/blog-briefing-room/news/leonardo-dicaprio-barack-obama-sxsl-climate-change
you can easily tell.
Hello Willard, Stick with AGW, it’s something you want to believe in.
Or…
Try it, you will like it.*
*You tube, not required.
P.S. Willard, I am very happy to see that you have moved beyond that pesky-pout-stage.
Steven Mosher | October 4, 2016 at 3:46 pm |” 1. we don’t do pairwise homogenization.”
–
“The homogenized Berkeley, NASA GISS and NOAA, all broadly agree with historical global climate model runs on this metric. ”
see
Berkeley Earth: raw versus adjusted temperature data
by Robert Rohde, Zeke Hausfather, Steve Mosher ******
–
Menne
Pairwise Homogenization Algorithm (PHA) Adjustment
The Pairwise Homogenization Algorithm was designed as an automated method of detecting and correcting localized temperature biases due to station moves, instrument changes, microsite changes, and meso-scale changes like urban heat islands.
The algorithm (whose code can be downloaded here) is conceptually simple: it assumes that climate change forced by external factors tends to happen regionally rather than locally. If one station is warming rapidly over a period of a decade a few kilometers from a number of stations that are cooling over the same period, the warming station is likely responding to localized effects (instrument changes, station moves, microsite changes, etc.) rather than a real climate signal.
To detect localized biases, the PHA iteratively goes through all the stations in the network and compares each of them to their surrounding neighbors.
–
For a laugh,
“Berkeley Earth developed a methodology for automating the adjustment process in part to answer the suspicions people had about the fairness of human aided adjustments.’
–
But the BEST
“determining the right amount of homogenization to best capture the local details is challenging,”
So when Homogenization is used it is not even used scientifically , that is to a specific formula, but to the whim of the plotters*.[*joke]
One determines the right amount of homogenization to be used depending on the results one needs.
“the fairness of human aided adjustments.'”
As often said.
TOO Funny.
Scene: Laurel and Hardy are walking down a street with an empty manhole cover. Sooner or later one of them will fall into it. Fast Forward: Scene: Discussion of role of dust in ice age terminations. Sooner or later discussion will revert back to alarmists and deniers. THE INEVITABLE MUST HAPPEN!
Now for a bit of good news. Our current Holocene interglacial is very similar to the Anglian interglacial 410,000 years ago. Orbital parameters are almost identical. This means we probably have another 15000 years to go before the next ice age begins to bite.
http://clivebest.com/blog/wp-content/uploads/2016/10/Anglian-Paleo-compare.png
The last spike in CO2 and Temp at time 0 are global warming. Temperatures might continue to rise by up to 3C by 2100 before returning slowly to normal by say 2300, assuming by then we cut emissions. After that it would probably be wise to keep CO2 levels above 300ppm indefinitely to avoid certain disaster.
Yes, thanks Clive, it is interesting, isn’t it.
We are working on this at present.
Would not a better description of the red plot be: ‘insolation at both poles simultaneously’, or simply ‘obliquity insolation’ ?
Actually the red plot represents 3 different things (within a scale factor)
1. Average summer insolation for both poles
2. Obliquity
3. Total annual insolation at either pole.
Number 3 is the fascinating one. It turns out that the elliptical orbit of the earth integrates out the precession enhanced insolation over a full orbit. Today the south pole is nearer to the sun during summer and receives ~20% more insolation at the equinox than the north pole does during its summer. However the summer is shorter as the earth speeds up passing through perihelion. The net result is that the integrated insolation each summer is equal for both poles. Only obliquity can increase the value and always equally for both poles !
One problem with the argument that the next ice age may not be far off is the belief that there is a deterministic cause-effect relation such that the conditions of a couple of variables 410,000 years ago if repeated, will automagically lead to a similar ice age. It seems likely to me that the situation is far more complicated.
As Clive hints but doesn’t show …
https://3.bp.blogspot.com/-Vr0yyLy3ME4/V_V5bS7xIQI/AAAAAAAABGs/OKNnuaSPVz8ljoFEqqYYOFN_DPapDAhXwCLcB/s1600/EDC3%2BCompare%2B415%2Bka.png
… at least one variable has a value nowhere near what it was ~410 ka ago.
>>at least one variable has a value nowhere near
>>what it was ~410 ka ago.
That is only relevant if Co2 has the influence that has been ascribed to it.
Hansen recalculated his climate sensitivity based upon interglacial temperature and Co2 data. But if interglacials are being predominently feedback-assisted by dust-albedo, then this naturally reduces the climate sensitivity that Hansen should have been calculating. In which case, the recent rise in Co2 may not be quite the problem that is claimed, and likewise Co2 may not be the saviour of another ice age that some imagine.
R
I don’t see CO2’s absorbing/emitting properties to be any more controversial than the albedo effects of dust and soot, Ralph.
Lotsa ifs. There are, of course, more than just Hansen’s ECS to CO2 estimates in the offing, and as you also should well know they span quite a range of values. Oddly enough, ECS estimates <= 0 are vanishingly rare in refereed literature. I reckon temperature/CO2 trends estimated by modern instrumentation (as opposed to those estimated by paleoclimate proxies) over the past century and a half or so have got more than a little something to do with that. YMMV.
“Our current Holocene interglacial is very similar to the Anglian interglacial 410,000 years ago. Orbital parameters are almost identical.”
Sorry Clive, but Chronis Tzedakis completely disagrees with you.
http://i1039.photobucket.com/albums/a475/Knownuthing/MIS11Tzedakis_zps4fubj4yy.png
You should remember this because we already had this conversation over your blog at the Anglian post:
http://clivebest.com/blog/?p=7089
“The Anglian interglacial, or MIS 11 is only similar to the Holocene (MIS 1) in eccentricity. Precession (65°N summer) and obliquity cannot be both aligned simultaneously between MIS 11 and MIS1. During MIS 1 both precession and obliquity peaked at ~11 and ~10 Ky BP, while during MIS 11 obliquity peaked at ~416 Ky BP, while precession peaked at ~408 Ky BP. This suggests that the Anglian interglacial could have been longer because the appropriate shift of both peaks created the equivalent of a broad peak.”
At the homologous position to current, with obliquities aligned (right panel), 65°N summer insolation in Anglian was at a peak and the interglacial got an extension. However at present in Holocene, 65°N summer insolation is at a valley so no extension will be granted. Holocene should have a typical duration and end in 1000-2000 years. I am rooting for 2000 although I have no skin in that game.
>>However at present in Holocene, 65°N summer
>>insolation is at a valley so no extension granted.
The Holocene has already been extended, in comparison to many interglacials, so it is already following the MIS 11 pattern.
Hi Javier,
The main difference is that the precession cycles are 180 degrees out of phase. So NH maximum insolation and SH maximum are inverted. If eccentricity was higher then we would be well into entering another ice age already. Probably now we can now wait for the next onset of the next NH minimum in 15K years time.
There is another amazing similarity. Both cycles have a Younger Dryas event !
Ralph,
“The Holocene has already been extended, in comparison to many interglacials, so it is already following the MIS 11 pattern.”
That’s clearly not correct. Average duration of interglacials is ~ 12-14,000 years since reaching modern average, as this wonderful graph from Oz4caster shows:
https://oz4caster.files.wordpress.com/2014/11/interglacial-warm-period-comparison.gif
Nothing indicates that Holocene is not about to plunge into a glacial period within the next 3000 years.
Clive,
“The main difference is that the precession cycles are 180 degrees out of phase.”
A crucial difference in my opinion. That difference in precession cannot be higher.
“If eccentricity was higher then we would be well into entering another ice age already. Probably we can now wait for the next onset of the next NH minimum in 15K years time.”
I fail to follow that logic. MIS 11 extension was granted because precession was 180 degrees out of phase, and because eccentricity was high. Now none of those conditions apply yet Holocene should also get an extension?
The real orbital analog to the Holocene is MIS 19. Same precession, same eccentricity and same obliquity. And MIS19 went down in about 1500 analog years, so I don’t see why it should be different this time, unless you want to play the CO2 exceptionality card.
Javier you are right on. They are wrong on many items.
The only differences I have with you are the solar/volcanic connection and the good possibility that I think a Dalton type Minimum is forthcoming.
>>I fail to follow that logic. MIS 11 extension was
>>granted because precession was 180 degrees
>>out of phase, and because eccentricity was high.
Actually, eccentricity was very low during MIS-11, 420 ky ago, the lowest it has been for 400 ky either side of that interglacial.
And what do you mean by precession being ‘out of phase’? I think you have misinterpreted that graph. Obliquity (blue) and precession (orange) were in phase during MIS-11.
https://s16.postimg.org/f548i94ph/dog4.jpg
Ralph,
The high eccentricity was a slip. I meant low.
The precession being 180° out of phase at MIS11 refers compared to the precession today, not to the obliquity then.
I do not think you have looked at the data in an unbiased way to see if interglacials follow obliquity or 65°N summer insolation. If we align interglacials by temperature, as Oz4caster showed, do you know what other thing also aligns?
http://i1039.photobucket.com/albums/a475/Knownuthing/interglacial%20comparison_zpskav1e3kr.png
Yes, obliquity also aligns at -17,500±1,500 years with respect to the point were temperatures reach modern normal. The only exception is the short interglacial MIS 7, that is clearly short because it did not start when it should have.
So why would obliquity align at -17,500±1,500 years? In my opinion is because that is the time it takes for the world to warm under increasing obliquity due to its thermal inertia,
Try to do that trick with 65°N summer insolation.
And average interglacials last about 20,000 years measured at the -4°C anomaly in Epica data. Obliquity cycles spend about 20,000 years above 23.25°, so the duration is consistent. Precession cycles are very short above their 50% level, about 10,000 years. Too short to account for interglacials.
And we know interglacials have depended on obliquity for millions of years.
Glacial inception (interglacial termination) is a different issue because it clearly depends more on 65°N summer insolation. In MIS 11, during 8,000 years the drop in obliquity was more than compensated by a big increase in 65°N summer insolation. Levels were elevated for another 5,000 years. Nothing to do with present conditions when the drop in obliquity coincides with low values of 65°N summer insolation.
Javier….
That insolation plot for MIS-7 looks wrong. On our plot from Laskar 2004, the insolation covers the temperature rise, just like all the others. While the one you display reduces before max temperature.
https://s1.postimg.org/4tq2e6am7/temps_insolation_Page_1.jpg
>>I do not think you have looked at the data in an
>>unbiased way to see if interglacials follow obliquity
>>or 65°N summer insolation.
Do remember that insolation at 65N also includes obliquity insolation. It is a combination total-insolation figure.
R
Ralph,
“That insolation plot for MIS-7 looks wrong.”
The graph is correct. What is represented is obliquity, as it is labeled.
I have the data in front of me:
Peak Obliquity (Lascar 2004)
-251 kyr 0.425947514877507 rads
Peak 65°N summer solstice insolation (Lascar 2004)
-253 kyr 540.662128393264 W/m2
-231 kyr 510.220346114812 W/m2
Epica Dome C temperature first reached 0°C (Jouzel 2007)
-243735.37 yr 0.21 °C
So the graph is correct. Peak obliquity took place 8000 years before MIS 7 reached 0°C. Peak insolation took place 10,000 years before and 12,000 years after.
“Do remember that insolation at 65N also includes obliquity insolation.”
Of course I do, but peaks and valleys do not usually coincide.
Now compare this graph where I have plotted the precession index to the graph above for obliquity.
http://i1039.photobucket.com/albums/a475/Knownuthing/interglacial%20comparison2_zpswktlpfnu.png
It is very clear that there is no synchronization between precession and temperatures, unlike obliquity, although there is a certain tendency for precession to peak at around 10,000 years before interglacial temperatures reach 0°C anomaly.
This also explains why MIS 11 was a long interglacial. Precession index went up when it should have been going down.
Now looking at these two graphs there is only one conclusion that can be drawn. Obliquity is pacing interglacials, not precession, not 65°N summer insolation, not dust.
>>The graph is correct. What is represented is
>>obliquity, as it is labeled.
Apologies, did not see that.
But that precession vs temperature graph looks completely wrong. I note it is labeled precession index, not insolation. But the PI should closely follow Milankovitch insolation. And the insolation index is very closely linked to temperature, as you can see in our graph above.
Try using the insolation values from Laskar 2004. I am sure you will get a different graph, with much greater synchrony. Your graph cannot be quite so different to ours.
Laskar 2004.
http://vo.imcce.fr/insola/earth/online/earth/online/index.php
R
And you will note in your obliquity graph, that MIS-7′ obliquity does not match with temperature at all. A theory must account for every eventuality, and the obliquity theory does not match or explain MIS-7. You need to revise the theory.
You also need to explain why many obliquity maximums do not produce an interglacial. You are back to the perennial missing interglacial problem again. So even if you believe in obliquity, you will still need dust-ice albedo to explain the missing interglacials.
Ralph,
“But that precession vs temperature graph looks completely wrong. I note it is labeled precession index, not insolation. But the PI should closely follow Milankovitch insolation.”
Precession index refers to climatic precession. Climatic precession describes the position of the perihelion with respect to the vernal equinox. It is obtained by multiplying e by the sin of the longitude of the perihelion, represented by the letter pomega (variant pi). The longitude of the perihelion is the resultant of adding two angles on different planes, the longitude of the ascending node and the argument of the periapsis (perihelion in this case).
https://upload.wikimedia.org/wikipedia/commons/thumb/e/eb/Orbit1.svg/555px-Orbit1.svg.png
Climatic precession is not linked to any latitude as it is a value that represents the precession of the planet, and therefore does not coincide with insolation, nor it should. Peaks in climatic precession indicate Northern hemisphere summer aphelion.
The main advantage of using precession instead of insolation is that it is not contaminated with obliquity, so it allows to separate the effects of obliquity or precession on interglacials.
I will do a graph with insolation for completeness and redo everything to check that all the data is correct as relying on work done by other person without checking has an intrinsic risk. I will post the results in an article about glacial-interglacial cycles that I will write in a couple of months to present my views and the evidence that supports them, if Judith is so kind as to publish it. It is certainly a polemical issue and I find myself once more defending a minoritarian position.
“the obliquity theory does not match or explain MIS-7. You need to revise the theory.”
No revision is necessary. Mis-7 should not have been an interglacial because when obliquity was at the bottom ready to start working, precession was in reverse and so the interglacial did not start on time. Later when precession came in line for high 65°N summer insolation it should not have started because it was too late to melt the ice sheets as obliquity was too advanced, but due to very high eccentricity 250 kyr ago, insolation was so high as to initiate an interglacial. Without time to melt the ice sheets completely the interglacial was aborted very early because of the fall in both obliquity and insolation. In LR04 there are two double interglacials MIS 7a and 7b, and MIS 15a and 15b, one at 200 kyr and the other at 600 kyr, the two periods when eccentricity was so high that interglacials could start at every obliquity cycle even if precession was not correctly aligned.
“You also need to explain why many obliquity maximums do not produce an interglacial.”
It is easily explained. Obliquity is no longer enough on its own since the mid Pleistocene transition. It needs a more or less correct alignment from precession and it needs either high eccentricity or the help of several feedbacks. It is still on command, but it needs troops for the fight. I can accept that one of those feedbacks is dust, and that is why I think your article is interesting and important, but we should not neglect other feedbacks that could be as important or more, as having very low sea levels with very large ice sheets lying low over continental platforms below high stand, ready to be melted by rising seas.
>>The main advantage of using precession instead of
>>insolation is that it is not contaminated with obliquity,
>>so it allows to separate the effects of obliquity or
>>precession on interglacials.
But the precession index reference point is not the one we want to use for deriving NH insolation. It gives the wrong azimuth and date, and therefore the wrong era. It looks like you are about 10,000 years out on that graph. The insolation maxima should coincide with the temperature maxima – according to Laskar and Epica3 data, they are very closely matched.
R
Ralph,
“But the precession index reference point is not the one we want to use for deriving NH insolation. It gives the wrong azimuth and date, and therefore the wrong era. It looks like you are about 10,000 years out on that graph. The insolation maxima should coincide with the temperature maxima – according to Laskar and Epica3 data, they are very closely matched.”
I think you are not following my argument. If you align interglacials according to temperature increase (when they start), obliquity gets aligned too, while precession doesn’t. Therefore obliquity is the deciding factor to start an interglacial and precession just collaborates. It is a powerful argument because a priori there is no reason why obliquity should align and precession shouldn’t, but it is clear that both cannot align as there is a drift between them. When they drift, interglacials follow obliquity, not precession. If they drift too much there is no interglacial unless eccentricity is very high as that can compensate.
It follows that if obliquity is the deciding factor to start an interglacial, dust is also a contributing factor.
Can you email me, so we can discuss further.
ralf dot ellis at me dot com
Thanks,
Ralph
>>you align interglacials according to temperature
>>increase, obliquity gets aligned too, while precession
>>doesn’t.
It does if you use precession-insolation, not the precession index. The index is measured from the zero azimuth, on March 21st. But we are looking for a precession index measured from June 21st. So your graph is at least 5,000 years misplaced.
Cheers,
Ralph
Forget my mention of the first point of Pisces, as that changes with apsidal precession. Perihelion is at 090 degrees, and aphelion is at 270 degrees – measured with respect to eccentricity. We are at about 270 degrees now, with the NH summer at aphelion.
.
But your graph is still wrong.
For MIS-1 you have the modern era at 12,000 years (from the start of the ice age). But you have the precession index at a maximum. In reality, the precession-insolation is at a minumum in the current era, and so you are 1/2 cycle out, or nearly 10,000 years.
I will try to mock up a diagram.
Ralph
Here is a very poor rendition of our graph, with precession and temp overlaid. I don’t know how to make the graph transparent, so I can only overlay two interglacials. MIS 11 & 9 plus MIS 7 & 5. This is taken from our fig 3, and as you can see, the precessional maxima precisely align with the temperature maxima in each case.
If you inverted your precession plots, you will end up with something like the proper presentation. You appear to be 170 degrees displaced from reality. Try the Laskar precession-insolation plot, and see the difference.
https://s12.postimg.org/kkvx80zfx/Precession_temp.jpg
You can find all ilk of vegetation reconstructions, but these two do support the general premise of desertification:
http://www.esd.ornl.gov/projects/qen/lastgla.gif
http://www.esd.ornl.gov/projects/qen/pres-pot.gif
Eddie: In the original paper, Ellis and Palmer referred to several papers dealing with desertification at the last LGM. I did not include that in my summary. Please provide a source for your diagram. You are right that there are “all ilk of vegetation reconstructions” and someone ought to do a thorough review and summary of these.
It’s an old source here:
http://www.esd.ornl.gov/projects/qen/nerc.html
a fairly extensive biblio:
http://www.esd.ornl.gov/projects/qen/refs.html
Thanks for that map, Eddie, which concurrs with the data I used in the paper. Some interesting points for you.
Yu did a survey of the Gobi and found that lake levels and precipitation was higher in the western region during the LGM than presently. Likewise, the PMIP precipitation models show that LGM precipitation was broardly similar to present day precipitation, in most regions. This strongly suggests that the large LGM Gobi desert was not an aridity desert, but a Co2 desert.
The eastern Asian desert reaches right up to the Arctic circle, and across to Alaska, which should have been covered by a vast ice sheet during the LGM. The reason why ice sheets did not form there, is that these regions were too close to the south westerly winds comming off the Gobi, and therefore too dusty. It was these high levels of dust that prevented ice sheet formation in NE Asia and western Alaska.
R
Eddie, I don’t know how they determined closed forest, but the “present” depiction of North America’s forest looks to be under estimating by not including pinion/juniper dominated woodlands of the west, which have expanded greatly over the last century, for various reasons.
Another open question:
Exactly how much of an albedo effect was there over LGM glaciers?
The ( presumably dusty ) Sahara has some very high albedo to begin with and that’s at a high solar elevations. At lower solar elevations exactly how much would dust scattered into snow change albedos?
http://ctms-stem.wikispaces.com/file/view/albedoearth_438x0_scale.jpg/480160106/albedoearth_438x0_scale.jpg
“Exactly how much” will never be known.
>>At lower solar elevations exactly how much would
>>dust scattered into snow change albedos?
Good question, and one that may explain the MPT.
Dust tends to sink into ice when it warms. This has the effect of making the ice appear high albedo in low Sun-angles, and low albedo in high Sun-angles.
For reasons that are too complex to explain here, precessional insolation is associated more with mid summer, when the Sun-angle is high. While obliquity insolation is associated more with the annual spring and autumn, when the Sun-angle is lower.
So large dusty ice sheets will be warmed and melted more by precession, than obliquity. This may well be why obliquity stopped being the controlling orbital factor after the MPT, because obliquity insolation cannot melt large ice sheets as effectively as precessional insolation.
The paradigm has to be weakly periodically (Milankovich) forced nonlinear-chaotic oscillation. Albedo driven ice growth positive feedback overruns into an unstable regime where Milankovich forcing is sufficient to initiate a feedback driven runaway ice shrinkage.
It’s interesting from figures 1 and 2 that in terms of area under the curve, the most recent glaciation was the most ice-voluminous in 800,000 years.
Dust maxima at glacial maxima may be at least partly due to plant dieback from CO2 starvation.
>>Dust maxima at glacial maxima may be at least
>>partly due to plant dieback from CO2 starvation.
Indeed. I devote several pages to that theory.
And surprisingly, the many papers I read about LGM treelines and LGM dust all danced around this topic without properly addressing it. So much so that quite a few papers had to distort moisture levels, precipitation, temperatures and lapse rates, to try and make sense of the LGM treeline data. And then they arrived at wholly unlikely and unreasonable lapse rates, which have been fed back into climate models.
But had these researchers invoked Co2 deprevation instead, then all these problems would have gone away, and the observed LGM treelines would have been fully explainable. So it is likely that all LGM models are using incorrect temperature and moisture data, because of misinterpreted treeline data.
Indeed, one seasoned researcher who contacted me did not know the difference between a Co2 concentration and a Co2 partial pressure at altitude. They claimed that since the concentration of Co2 did not change with altitude, then plants can live at any altitude. I did ask the researcher to climb to the top of Mt Everest, to see if they became hypoxic (just as plants become hypo-Co2-ic). After all, the concentration of oxygen is the same on Mt Everest as at sea level……
So there you go – most of the climate models have been loaded with incorrect temperature and moisture data since these treeline investigations were made back in the 1980s. And the arbitary adjustments they made to make the data fit was to cool tropical LGM sea level temperatures by 2 degrees c. So it may well be that in reality tropical LGM termperatures were broadly similar to modern temperatures – perhaps only 2 degrees cooler instead of the 4 degrees cooler that is claimed.
R
“Dust maxima at glacial maxima may be at least partly due to plant dieback from CO2 starvation” was a principal theme of Ellis and Palmer, and I forgot to emphasize that in my summary.
That would be of more interest for present considerations *IF* we were flirting right now with CO2 levels of < 200 ppm as were seen during the LGM. Even then, I would think it necessary to *also* consider *at least* temperature and (by extension) precipitation as factors. Plants need more than just food to grow, yes?
As well, looking at the dust flux curves from the Antarctica Dome C ice cores, you will note that they fall to practically zero when CO2 reaches ~240 ppm and temperatures have risen about the halfway mark between glacial maximum and the interglacial max.
Brandonrgates, are you considering that the lower latitude ends of the glaciers would be concentrating the dust as they melt and shrink? They would not look like the Dome C ice cores. They would get progressively dirtier decreasing albedo, producing a positive feedback for continued melting until interglacial stability. I agree the overall dust effect is to be negative feedback that perhaps saved us from permanent glaciation. It’s good theory in finding a mechanism with ability to overpower cooling’s positive feedbacks or ice albedo and diminishing atmospheric GHG..
Ron Graf,
More my thinking to this point has been that as glaciers recede, what’s under them has a lower albedo. The effect you describe would certainly contribute. As ever, these things want quantification, and as ever they’re lacking.
I reckon not, which is a problem.
I don’t follow. I think it’s actually contrary to the central thesis of this article about dust as a trigger for glacial terminations, with which I don’t have any strong objection. I have more of a problem with Ralph’s ancillary arguments about the implications for CO2 forcing or Donald’s plug just above on plant starvation (specifically, the implication that it’s relevant *today*); they leave me rather unconvinced.
Brandonrgates says: I don’t follow. I think it’s [dust effect being negative feedback] actually contrary to the central thesis of this article about dust as a trigger for glacial terminations, with which I don’t have any strong objection.
The dust to precipitation ratio increases as the global mean temp drops. This decreases the albedo and which warms global mean temp. That makes dust a negative feedback effect because there had to be cooling first to get its warming effect. The dust is not a positive warming feedback until a glacial maximum is reached and the ice surface gets progressively less reflective with ongoing melt. This is unlike CO2 and water vapor, which are positive feedbacks in both directions.
Ellis and Palmer provided several references regarding the state of vegetation during the LGM. I can add a couple more: (Prentice et al. 2010 “Global vegetation and terrestrial carbon cycle changes after the last ice age” and Oishi and Ouchi (2013) “Influence of dynamic vegetation on climate change and terrestrial carbon storage in the Last Glacial Maximum”.
Surely, a combination of reduced temperature and precipitation in addition to CO2 starvation was responsible for generating worldwide dust sources from depleted vegetation. In addition, as Ron Graf points out, glacionic dust, while not in the ice cores, was a likely participant in the southern flanks of the ice sheets.
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Donald Rapp and Ral Ellis, is this short summary correct? :
The “dust on ice sheets” research provides a plausible explanation for why change in CO2 concentration lags change in temperature through the glacial inter-glacial cycles. The ~80,000 year cooling period from interglacial to glacial maximum occurred as CO2 concentration. The ~10,000 year warming following each glacial maximum occurred as the ice retreated due (in part) to the dust on its surface. Ralf Ellis responded to one of my comments on CE explaining that the dust was caused primarily by the ‘CO2 drought’, not by precipitation drought https://judithcurry.com/2016/10/02/dust-deposition-on-ice-sheets-a-mechanism-for-termination-of-ice-ages/#comment-815336 .
http://www.esd.ornl.gov/projects/qen/lastgla.gif
http://www.esd.ornl.gov/projects/qen/pres-pot.gif
(h/t: Turbulent Eddie | October 5, 2016 at 8:50 am https://judithcurry.com/2016/10/02/dust-deposition-on-ice-sheets-a-mechanism-for-termination-of-ice-ages/#comment-815349 )
Many researchers have estimated climate sensitivity using the change in temperatures and change in CO2 concentration through the glacial interglacial cycles. However, assuming CO2 is the main control knob and ignoring the effect of dust may cause climate sensitivity to be overestimated.
By the way, regarding the modelling, the GCMs have consistently failed to be able to lift the planet out of an ice age using CO2. The inclusion of the dust does lift the planet out of the ice ages.
I know from experience how effectively dust on snow works: I lived in Manitoba, Canada for 6½ years. In spring we spread a thin dusting of black soil over the snow on the tennis courts. The snow melted within a few sunny days instead of a couple of weeks.
typo: sentence should read: “The ~80,000 year cooling period from interglacial to glacial maximum occurred as CO2 concentration declined.”
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The rise and fall of dust in ice cores is a variable. Ice sheet growth and decay is a variable. Linking the two in a cause and effect relationship leads to one of the most common errors and bias in research: The disregard of a confounding variable.
A warmed wetter world would have a tremendous amount of vegetation that would turn into detritus as a result of that warming (note how thick paleosoils can get when the world has been warmer and wetter). A colder, dryer world, with high winds, would have a tremendous amount of that detritus up in the air.
So I ask what could make for a warmer wetter world, and what could make for a colder dryer world. One would logically look for a very large and variable source of water vapor. Something wet that could soak up tremendous amounts of heat as well as give up tremendous amounts of heat.
hmmm…