by Judith Curry
Part I addressed the mid-20th century surface temperature “bump” (peaking circa 1940). The IPCC AR4 states in the figure caption for FAQ3.1, Figure 1:
From about 1940 to 1970 the increasing industrialisation following World War II increased pollution in the Northern Hemisphere, contributing to cooling, and increases in carbon dioxide and other greenhouse gases dominate the observed warming after the mid-1970s.
In Chapter 9, a more detailed analysis is provided:
Differences between simulations including greenhouse gas forcing only and those that also include the cooling effects of sulphate aerosols (e.g., Tett et al., 2002) indicate that the cooling effects of sulphate aerosols may account for some of the lack of observational warming between 1950 and 1970, despite increasing greenhouse gas concentrations, as was proposed by Schwartz (1993). In contrast, Nagashima et al. (2006) find that carbonaceous aerosols are required for the MIROC model (see Table 8.1 for a description) to provide a statistically consistent representation of observed changes in near-surface temperature in the middle part of the 20th century. The mid-century cooling that the model simulates in some regions is also observed, and is caused in the model by regional negative surface forcing from organic and black carbon associated with biomass burning. Variations in the Atlantic Multi-decadal Oscillation (see Section 3.6.6 for a more detailed discussion) could account for some of the evolution of global and hemispheric mean temperatures during the instrumental period (Schlesinger and Ramankutty, 1994; Andronova and Schlesinger, 2000; Delworth and Mann, 2000); Knight et al. (2005) estimate that variations in the Atlantic Multi-decadal Oscillation could account for up to 0.2°C peak-to-trough variability in NH mean decadal temperatures.
Skeptical Science provides a detailed explanation for the aerosol-driven mechanism for the mid-century cooling. It concludes with:
So what caused the mid-century cooling to end? The main cause of the sudden shift in global temperature trends was the passage of Clean Air Acts by various countries in response to air pollution and acid rain. The USA, for example, first passed its Clean Air Act in 1970, with amendments in 1977 and 1990. Coincidentally, the US Supreme Court (inMassachusetts v. EPA) and EPA (in an endangerment finding) also recently decided that greenhouse gases qualify as ‘air pollutants’ in the Clean Air Act and must be regulated accordingly.
Smith et al. paper
There is a new paper out that is very relevant to this issue (see also discussion at WUWT):
Anthropogenic sulfur dioxide emissions: 1850-2005
S.J. Smith, J. van Aardenne, Z. Klimont, R.J. Andres, A. Volke, and S. Delgado Arias
Abstract. Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850– 2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, inter- national shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and interna- tional shipping. Emissions were distributed on a 0.5◦ grid by sector for use in coordinated climate model experiments.
The graphs show a broad peak from about 1970-1990, then a 10-15% decrease from 1990 to 2000 (with a slight increase between 2000 and 2005). Eyeballing the graph shows emissions in Gg:
- 1910-1940: 25,000 – 50,000 Gg
- 1940-1970: 50,000 – 125,000 Gg
- 1970-2000: 125,000 – 110,000 Gg
The drop in global sulfate emissions after 1970 just isn’t all that large; while there were large decreases in the U.S. and Europe, developing economies (esp Asia) were rapidly increasing. So it it seems to be more accurate to state that there was a leveling off around 1970, with a small decrease in the 1990’s, then an increase beginning ca 2000.
So how does the aerosol explanation hold up for the mid century cooling? There is a marked change in the slope of emissions at 1950; hence the aerosols don’t seem to be a convincing explanation for the large cooling observed in the 1940’s.
And how does the aerosol explanation hold up for the resumption of warming ca 1970? Again, there is a marked change in slope ca 1970, where the emissions level off until 1990; there is no global reduction in total emissions between 1970 and 1990.
JC’s conclusion: It seems implausible to attribute the mid century cooling and the resumption of warming to an increase in sulfate emissions following WWII and then a decrease ca 1970 following the Clean Air Acts. There may be some sort of complicated lag that may be evident to support the 1970-2000 warming (from the increase during the period 19501970), but the large cooling from 1940-1950 cannot be explained by aerosol forcing.
Isn’t it also possible that factors OTHER than strictly human emissions could have played a part in the rise and fall of temperatures in the mid 20th century? I’m not trying to downplay AGW, but come on! The level of certainty displayed by the writers is staggering to me.
That is the problem.
Inventing an air of “certainty” that is totally unjustified by the data.
In fairness, though, climatologists did not invent this technique. The space science community had developed this into a fine art before the politicians decided they could to start pouring public funds into climate research instead.
With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
Are the numbers given by the Smith et all paper different to the ones used by the papers in the last IPCC report? If so how different?
The numbers are not quite the same as given in the IPCC AR4, which tells that the global emissions were 73 TgS in 1980 and 54 TgS in 2000 referring to a 2005 paper by D.I. Stern. The paper of Smith et al has a somewhat lower value (65 TgS) for 1980, but essentially the same number (53 TgS) for 2000. The AR4 report does not contain more complete history data as far as can see although the Stern paper covers 1850-2000 according to its title. A slightly newer paper by Stern is referred to in the Smith paper.
Thanks for the comparison.
I don’t understand the relevance of the Smith et all paper to sulfate attribution. It’s presented in this post as being something that seriously undermines the IPCC conclusions.
Pekka,
“This picture is one of my favorites in explaining, how important CO2 is
http://en.wikipedia.org/wiki/File:ModtranRadiativeForcingDoubleCO2.png
This is a model calculation and I do not refer to it as a precise description of the real atmosphere, but it explains very well the basic mechanism.”
Thank you for the picture. The one I saw had a lot more information. It was comparing the spikes of CO2 at 14~16um wavelengths with the spectrum of H2O IR wavelengths recorded with spectrometer. Its obvious to me that H2O IR spectrum is way huge compared with CO2’s 14~16um. H2O is only slightly less absorptive than CO2 at 15um, the rest of the IR spectrum that H2O absorb dwarf the CO2’s radiation absorption.
You might have read a lot of radiation papers and a lot more than I have read. You might have a lot of knowledge modeling and understanding of this Modtran 3 v1.3 and other models and probably an expert in this model area. With the hidding of data (CRU) from the public assess and outbreak of the climategate, I would not trust these modeling result with a 100%. I am not an expert in this modeling and do not intend to study the details, the assumptions, the errors (such as the 260.12 W/m2 and the 256.72 W/m2 at 300 and 600ppm respectively whereas K&T 235 W/m2 (1997) and 239 W/m2 (2007) Delta F is very much questionable, i.e. anyone’s guesses) involved. Models are just models, not real and so is K&T’s back radiation of 324 W/m2, not real.
That modeling picture at 300ppm CO2 with 260.12 W/m2 radiation emission seems from CO2 is very misleading to the general public.
“The Earth warms, when radiation cannot escape freely from the warm layers of the atmosphere or the even warmer surface.”
Agreed to a certain extent, especially under direct sunlight. Radiation from the Earth surface under direct sunlight may be absorbed, deflected, reflected … but remember, radiation photons travel at the speed of light and does not stay long in the atmosphere.
Since radiation is radiated at all directions, half of the Earth surface radiates at night freely to space at the speed of light towards outer space. Only a small portion (about 1%) absorbs by GHGs, but that portion is re-emitted almost instantaneously. Remember the molecules or atoms only occupied a very small volume of the space. Most IR photons (99%) or IR radiation just pass straight thru to the outer space. Even CO2 at the TOA is doubled, tripled or quadrupled, the interception (or absorption) of the Earth surface IR radiation (heat quantity) by CO2 is just trivial.
Half the Earth surface at daytime assuming also radiates freely to the space during the daytime. However, due to the Sun’s stronger light radiation, all IR radiations either absorb by the Sun’s direct radiation, push back, defract, deflect, reflect or whatever applicable theory applys and so the Earth surface heat up instead of cool down. Under direct solar radiation, the Earth surface warms up, water molecules on the Earth surface absorb solar radiation then bring away heat thru evaporation (enormous amount of latent heat), convection of air carry away the Earth surface heat, rain falls bring down Earth’s surface temperatures, ocean flows bring down the ocean surface temperatures etc.
“When radiation can escape only from the uppermost cold layers the effect is at its strongest.”
I agree that radiation can escape only from the uppermost cold layer since all radiation has to travel thru that last layer of distance before leaving the Earth but you need to clarify what do you mean by “the effect is at its strongest”?
“From this picture you can see that this happens most influentially in the wavenumber range 600-750 cm^-1. This fact is totally due to the strong absorption of CO2 even at the low density of the uppermost troposphere.”
Assume the picture to be trustworthy, however strong CO2 absorption is, only 0.039% at the wavenumber range 600-750 cm^-1, a trivial radiation amount of IR radiation.
“Water is the dominant factor at almost all other wavenumbers, but it is as efficient only at lowest wavenumbers that carry little energy anyway. “
I disagree especially the spectrometer record comparison show that H2O is almost comparable at 14~16um. How do you get the idea that “H2O is as efficient only at lowest wavenumbers that carry little energy anyway.” Carry little energy? Please elaborate with some figures/data, thanks.
“The picture tells also, how additional CO2 modifies the result, but that is not may main point here.” Any error assessments of the result?
“Drawing the picture as it is drawn here is illuminating in the way that equal area corresponds here always to equal radiative energy. The dip produced by CO2 is very important indeed.”
OK. With the benefit of doubt, I assume this picture to be correct. I can go a bit further even assume 100% CO2 absorption efficiency in the wavenumber range 600-750 cm^-1, only 0.039% CO2, no big deal at all.
Pekka,
Pekka,
http://en.wikipedia.org/wiki/File:ModtranRadiativeForcingDoubleCO2.png
Just curious how do you interpret the drop in temperatures in the wavenumber range 600-750 cm^-1 from around 280K to 220K.
Sam NC,
No picture and no statement or explanation in a web discussion can prove you, what is right. The value of pictures like this one is in the help they provide for improving the understanding. They tell in a simplified way, what happens, they do not prove it, but knowing the description gives a good starting point for evaluating evidence.
When you cannot do all the measurements yourself, the best that you can do is to search the literature yourself. Accepting help from web pages in this final step may be unwise, because the web pages have often an agenda. They may present a biased collection to the point of distorting totally the picture. It is better to use google (or google scholar) to search from all information, but of course this is possible only when you have learned enough about the explanations. The role of the own searches is strongest in the final step of judging the evidence. On earlier steps one has to use other sources like textbooks and specialized web pages.
This picture from Wiki is good for the learning phase. The interpretation of temperatures is that they tell the average temperature of the layers, where the radiation originates. Thus 220K tells that the 15 um radiation that leaves the troposphere originates at the temperature of 220K. This is the temperature of the top of troposphere. Thus all radiation comes from the top, because all 15 um radiation from lower layers is absorbed on the way up and heats the absorbing layers (heating is done also by convection), finally the radiation from the top of troposphere can reach stratosphere, where the density of air and of CO2 as a component of air is so low that the radiation does not get absorbed rapidly.
The small concentration of 0.039% CO2 is enough to assure absorption within tens of meters in the low troposphere. At the top of troposphere the distance is something like one kilometer (less at the center of the strongest absorption, but that is a representative number). The constant value close to 220K tells that the penetration is so weak at all those wavelengths that practically no radiation comes from significantly warmer lower layers.
The strength of the CO2 absorption is shown also in the antarctic measurements of downwelling radiation shown in the paper I linked. Here the link again. The effect is perhaps shown most clearly in the right picture of Figure 3. There we see that the downwelling radiation comes from essentially the same temperature than the surface has at wavenumbers 600-730 and 1500-1800 cm^-1. The former is the CO2 band, the upper corresponds to the strongest absorption by water (the range around 2300 is again due to CO2). Here we look at the downwelling radiation. Thus the strongest absorption allows only the the radiation of the very lowest layers reach the surface. This is the radiation that is often called back radiation. Here the radiation from CO2 in the 600-730 band carries more energy, because the temperatures are so low that the radiation at the higher wavenumbers is weak. The effect of the CO2 absorption is so large because the band is close to the maximum of the spectrum drawn in the way of the Wiki picture or the left picture of this publication.
The satellite images presented by John Nielsen-Gammon in his blog
http://blogs.chron.com/climateabyss/2010/12/the_tyndall_gas_effect_part_2_seeing_is_believing.html
describe these same things using real observations from satellites, i.e. looking down from the space. The blog explains, what these images tell.
At long last. A prominent climate scientist stating the obvious. Not to mention that anthropogenic sulfates have a residence time in the troposphere of 1-2 weeks so their cooling effect should be evident over industrialized areas, such as Eastern China. Nothing of the like is observed.
Still, I find it intriguing that so many papers have been published around the anthropogenic sulfate cooling effect and, as far as I know, none concluding what JC has just stated.
The ‘just so’ story has many chapters.
Thanks for this post, Judith, it is timely for me. One thing that is not generally appreciated is that some models don’t show any cooling for the 1945-1970 period. See here, Figure 2, for the GISS Model E results. They contain a volcanic dip around 1960 but no general decrease for the period. Recently I’ve been expanding my research in this area to include other models as well, I’ll report back if I find anything.
w.
Willis, If the dip is due to a natural cycle you wont find the GCMs matching it.
you Might find one instance of a ensemble matching it, but only by chance.
The only way a GCM could match the cycles was if it was initialized with the state of the ocean being exactly correct. For example, if you started at 1900 you’d have to initialize the ocean model to “state” of the ocean ( think motion vectors for currents) in 1900. When you average over a bunch of runs the dips and peaks smooth out. So, a GCM might reproduce an El Nino frequency properly, but getting the exact timing is not likely. Those cycles are not programmed in, they emerge. The best you can hope for is to get the frequency and average amplitude correct.
This is why “coupling” is such an interesting question. If “coupling” leads to another emergent behavior, then investiagting that would require a ton of runs
Mosh, my understanding was that the standard explanation for the post-1940’s cooling was that the effect of the reflective aerosols overwhelmed the warming effect of the CO2 … am I wrong?
I don’t think you are wrong. But you have the aerosols forcing file, correct?
It might be interesting to look at the various models and see if any of them showed a relative cooling in the time:
1. Did the whole multi model mean?
2. did any single run?
3. did any given model.
I think when I first posted on ModelE (over at CA) I noted that it misses these “transient” events. I can understand that if the transient is an “internal variation” or unforced variation, but if its a forced variation I’d expect the average behavior to be in the right direction.
BTW, That’s a fair test I think. Just in doing diagnostic runs I think youd check to ensure that you got good response from transient changes in external forcing.. Take a loot at the attribution runs
where I think ( i could be wrong) there was some “tuning”
(ah crap, that’ll start a fight)
It really would be nice to get some documentation on the model prep and test cases ( change code, test model)
I have the forcings file used by the GISS Model E. Unfortunately, I’ve been unable to find forcings for any other models. The CMIP3 claims that forcings are available for FGOALS and one other model, but I’ve been unable to find them.
Anyone who knows where these forcing files can be found (or any forcing files for the twentieth century model hindcasts), please let me know.
w.
A follow up question on the comparisons: why does Model E overpronounce the Mt Pinatubo and El Chinchon eruptions as clearly shown in the comparisons? Might this be an indicator of overestimated climate sensitivity in Model E?
bah, this reply was intented as a follow up on my post which is below.
Hi Willis,
I made similar comparisons yesterday:
Model E vs Gistemp:
http://img208.imageshack.us/img208/3639/modelegistemp.jpg
R^2 is 0,61 and with 37mo smoothing 0,84
Model E vs HadCRUT3:
http://img836.imageshack.us/img836/3391/modelehadcrut3.jpg
R^2 is also 0,61, but with 37mo smoothing its worse whan with gistemp, only 0,76
There also seems to be a divergence in the amplitude of multidecadal signal in gistemp vs hadcrut3:
http://img403.imageshack.us/img403/656/hadcrutgistemp.jpg
Is this a coinsidence? Now that AMO, ENSO and PDO have been largely identified as internal variations, and Model E does clearly not reproduce these dynamics, I have no trust in gistemp since they visibly have reduced this signal.
This blink comparator clearly illustrates how the homogenity adjustments of gistemp reduce the multidecadal dynamics (and Nuuk is at airport):
http://i.picasion.com/pic38/5cf8cfc4d189899c717dac404b401597.gif
Note, that the y-axis also increases by 1 in the homogenized version, and the start and ending points of the graphs stay put!!
Willis, you’re right.
But I would rather highlight that (see figures provided by Juakola or FAQ8.1, Fig 1 in AR4 : http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-8-1.html) :
1) None of the models (not only GISS one) is able to reproduce the correct warming rate for 1910 – 1940 period (+0,06°C per decade produced by models instead of +0,15°C per decade observed)
2) None of the models is able to reproduce the 1940 – 1970 cooling periode
3) Most significant temperature drops produced by models are short and actually correspond to a major volcanic eruption (Agung in 1964, El Chichon in 1982 and Pinatubo in April 1991) => no cooling possible with models, except when using volcanic forcing.
Conclusion : models are biased and invalidated.
1940 bump can be associated to a huge PDO shift as shown here : http://www.woodfortrees.org/plot/hadcrut3vgl/from:1880/mean:120/normalise/plot/jisao-pdo/from:1880/mean:120/normalise
Eric: Sorry for contributing so late. You wrote, “1940 bump can be associated to a huge PDO shift as shown here”
The PDO does NOT represent the SST anomalies of the North Pacific, north of 20N. It also does NOT represent the North Pacific SST anomalies after the global SST anomalies have been removed.
The PDO is the leading principal component of those SST anomalies (a statistically created dataset), after the global SST anomalies have been removed. On a decadal basis, the SST anomalies of the North Pacific are inversely related to the PDO.
http://i52.tinypic.com/15oz3eo.jpg
I discussed that in this post:
http://bobtisdale.blogspot.com/2010/09/inverse-relationship-between-pdo-and.html
And if we compare detrended North Pacific SST anomalies to detrended North Atlantic SST anomalies (the AMO) we can see that multidecadal variations of the SST anomalies of the two ocean basins are similar in magnitude and they run in and out of synch.
http://i56.tinypic.com/t9zhua.jpg
Refer to:
http://bobtisdale.blogspot.com/2010/09/introduction-to-enso-amo-and-pdo-part-3.html
Also, the vast majority of the 1940s hump is in the Southern Hemisphere SST anomalies, especially the Indian Ocean.
In the USA , SO2 emissions from coal fired power were not regulated until around 1995 (for acid rain). Prior to that we build a huge fleet of coal fired plants during the 1970’s, something like what China is dong now, with no SO2 controls and burning high sulfur coal. We basically switched to coal during the 1970’s. So US SO2 emissions should have risen dramatically during the 1970’s and 1980’s.
More generally, the 1970 CAA was voluntary and achieved little. The 1977 CAA took many years to take effect, with little if any in the 1970’s. The regulatory process took about a decade to unfold. It regulated things like VOC’s (for ozone), carbon monoxide and particulates.
Mikel:
The short residence time of sulfate aerosols is well documented. However, the value you cite for the sulfate residence time does not preclude sulfates from contributing an appreciable hemispheric-mean or global-mean radiative forcing.
OK. But could you please explain how sulfates can produce such a strong negative radiative effect (almost the same magnitude as CO2, according to the IPCC) without being able to actually cool the regions over which they are located?
Thanks,
Mikel
Sulfates do indeed exert a cooling at the regions over which they are located.
Could you please illustrate that assertion with any instrumental evidence? This is where sulfates are currently located (and have been for about 1-2 decades): http://upload.wikimedia.org/wikipedia/commons/6/67/Gocart_sulfate_optical_thickness.png
Thanks,
Mikel
Couldn’t find a linkable figure for the sulfate radiative forcing, but IPCC figure 2.12 (http://ipcc.ch/graphics/ar4-wg1/jpg/fig-2-12.jpg) panel (f) shows an estimate of the surface radiative forcing from all aerosols. This is some complex mixture of models and observations. Note that your picture of sulfate optical thickness is as well, as there is no instrument capable of making a global map of sulfate optical thickness. However, there are many studies in the literature that quantify the surface radiative cooling as a function of optical thickness for locations with the required instrumentation.
By instrumental evidence of cooling I meant instrumental evidence of lower temperatures in the regions most affected by sulfate aerosols.
http://data.giss.nasa.gov/gistemp/maps/
You can plot the temp anomaly for the cooling period relative to the preceeding period. The GISTEMP data shows the cooling over Europe and USA where the economic activity grew.
This shouldn’t be so complicated. The largest sulfate concentrations are by far located over eastern Asia, both in Eric’s link and in Wikipedia´s reconstruction (which is obviously no big surprise). Where in those GISTEMP maps do you see that eastern Asia has cooled in the last decades? Also note that the IPCC claims that aerosols are practically canceling all CO2 warming. This means that sulfates, that, unlike CO2, are very unevenly distributed, should produce a particularly strong cooling over the regions they affect most.
Oh, but it is complicated. As so many posts on this blog can attest, there are many factors contributing to the temperature anomaly in any one place at any time in history. Over Asia during the last couple of decades the aerosol load has been heavily fortified with soot and black carbon. As much as one-half of the atmospheric warming over India has been attributed to the direct absorption of solar radiation by dark carbonaceous particles. The carbonaceous aerosols strongly heat the atmosphere while strongly cooling the surface. Meanwhile, the greenhouse gases warm both and the sulfate aerosols mostly just cool the surface. Disentangling the sulfate cooling signal from this (as well as from the variability in regional circulation – some of which might be induced by the aerosol radiative forcing) cannot be done simply. And will likely not be revealed in a cursory study of wikipedia imagery.
Regardless of the complications it is clear that if aerosols have a strong cooling influence as has been claimed then there should be a statistically significant correlation between industrial output locations and a lack of warming in those areas since this is where the aerosols would be most dense. I have searched for a paper showing such a correlation but have yet to find one. Perhaps someone knows of such a paper?
In order for aerosols to have a significant part in global cooling, it needs to be blow a trillion times just like the effect of CO2, blown up trillions of trillions times already.
So, in essence, what you’re saying is that anthro sulfates mask the effect of anthro GHGs, but, in turn, other anthro aerosols mask the effect of sulfates.
Well… OK, why not? But in that case, the global aerosol forcing cannot be so negative (-1.2 W/m2: IPCC). If we cannot even observe the effect of cooling aerosols due to the warming aerosols, the net aerosol forcing must be kind of flat.
I’m quite willing to read about all the complications of analyzing the aerosol effects, but the narrative has to carry some logic and the numbers must add up. Just to begin with, *some* instrumentally observed cooling due to sulfates should exist somewhere in the temp records.
Let’s take Shanghai, China, in the middle of the sulfate blob. http://data.giss.nasa.gov/gistemp/station_data/ (GHCN ID 205583620001) Any cooling since, say, 1980? Definitely not. Ah, well, perhaps the cooling was masked by UHI? Let’s go to neighboring, much smaller Yichang (ID 205574610002) or Dachen Lao (ID 205586660000) Again lo luck.
Mikel: I think this was the main point of the NRC report on radiative forcing, “expanding the concept” (http://www.nap.edu/openbook.php?isbn=0309095069). The radiative forcing value you see in the IPCC report is the forcing at the top of the atmosphere. That works reasonably well for GHGs, but begins to break down when you talk about aerosols – particularly the black carbon aerosols which have a very weak radiative forcing at the top of the atmosphere relative to their forcing in the atmosphere or at the surface. Indeed, the numbers must “add up”, but one must consider the vertical distribution of the forcing and account for the fact that the different forcing agents act in different ways. Also, note that Shanghai is in the middle of a sulfate blob, but is also in the middle of a black carbon blob.
Thanks for the reference, Eric. I’ll read it tomorrow. Perhaps I’ll finally be able to understand why so many intelligent people are so confident that aerosols have such a great cooling effect on the surface, even though we cannot see it in the surface instrumental record.
Even though we cannot see it in the surface intrumental record of the regions right below the cooling aerosol specimens, that is.
OK, Eric. I’ve read chapter 4 of the report (Rethinking the Global Radiative Forcing Concept). Nothing much new there, having read Ramanathan´s studies on Asian aerosols and others. But now I’m really puzzled. Why do you think that this report supports the notion that sulfate cooling, while important, should not be evident over the affected regions? Indeed, the estimated TOA forcing is not the correct metric to assess the effects of aerosols on the surface. But the estimated surface forcing of all aerosols is on average *much larger*, especially over Asia. And yet we don’t see it in the surface thermometers?
Surely I’m missing something.
Mikel: Evidently our thread has gotten too deep for me to reply to your last comment. Hopefully you’ll find this here. In some regions over a sufficient period of time the global dimming signal from aerosol forcing is detectable in surface measurements of solar irradiance. However, my point is merely that when looking at regional variability of near-surface air temperature, there are a myriad factors at play, even in regions of high sulfate loading. The one I have emphasized here is the black carbon absorption which heats the atmosphere. BC concentrations have been growing in many of the same places that also have high sulfate loading. Then, of course, there is the increasing GHG forcing. Also, there are potentially circulation changes. Asia is dominated by the thermally-direct monsoon circulation. Therefore, direct heating of the atmosphere, such as by BC aerosols, are likely impacting the circulation. GHGs may also be altering regional circulations. What effect could these circulation responses be having on regional temperature trends? Your guess is as good as mine. Maybe small, but I don’t know. Global-averaged surface temperature is significantly impacted by top-of-atmosphere energy balance (although this blog is a good one for discussions of the problems even with that simplified view). But trying to apply a simple top-of-atmosphere energy balance argument to regional temperature trends seems too gross a simplification to me.
Thanks for the effort Eric but I’m not getting it. Regardless of the many things that may be happening (or not) to the regional circulation over Asia, if we have a persistent load of SO2 and BC that are supposed to produce a strong cooling effect on the surface, we should be able to see it in the form of … surface cooling.
” Over Asia during the last couple of decades the aerosol load has been heavily fortified with soot and black carbon. As much as one-half of the atmospheric warming over India has been attributed to the direct absorption of solar radiation by dark carbonaceous particles. The carbonaceous aerosols strongly heat the atmosphere while strongly cooling the surface.”
You have any data to prove?
This is the reference – and a nice review of the BC aerosol problem: doi:10.1038/ngeo156
Mikel,
Has anybody yet asscribed the slow down in temp increase post 2000 to aerosols? All I’m aware of is that aersols have been implicated in the mid-20th century ‘cooling’ and in that case the pattern of cooling as shown by the NASA GISS maps is pretty good. The post-2000 increase in aerosols is a relatively new finding. I realise there has been a lot of speculation here and at WUWT that this will be used to explain away the post-2000 slowdown but I don’t know this speculation has yet made it into the science. You could be arguing a strawman here Mikel.
No, I must disagree. The pattern of cooling in the GISTEMP maps is not at all good if you try to explain the post-’44 drop in temps with (esentially) Northern Hemisphere aerosols. It is also visible in the Southern Extratropics, where industrial aerosols were absent. If you go to the HadCRUT series, the cooling was actually stronger in the SH than in the NH:
http://hadobs.metoffice.com/hadcrut3/diagnostics/hemispheric/northern/
http://hadobs.metoffice.com/hadcrut3/diagnostics/hemispheric/southern/
Mikel – I don’t interpret the data the same way. The temperature record between 1940 and 1950 shows a pronounced spike followed by a dip. This is almost certainly attributable to internal climate dynamics (ENSO, PDO, AMO) – aerosols probably have nothing to do with it.
The critical intervals are what follows – from 1950 to 1977, and then from 1977 onward. Between 1950 and 1977, the NH shows a flat temperature profile, while the SH shows a slightly rising one. After 1977, temperature rises more steeply.
Regarding a separate comment you make, the aerosol effects have been quantified by measuring reduced surface solar insolation under both clear sky and all sky conditions. For some relevant links, see my Comment below, as well as links cited by HR further down in the thread.
Fred, I guess what you say is possible. Let’s attribute internal climate dynamics to whatever we don’t understand in the temperature record and then the rest is much better explainable by anthropogenic influences. But I see too many problems to apply Occam’r razor and take that explanation as the best:
1) The SH cooled in the mid-century
2) Sulfate load does not seem to cool the affected areas
3) As mentioned below by Peter Webster, the Arctic experienced an enhanced mid-century cooling
In view of all this empirical evidence, is it also not possible that anthro sulfates are just not as powerful a forcing as the IPCC makes them to be? (remember that the IPCC itself assigns a low level of scientific understanding to aerosols).
Anyway, I still need to read your and Eric’s link.
Thanks.
This paper has an interesting perspective on the mid-20th century issue.
Try again:
This paper has an interesting perspective on the mid-20th century issue.
Nuclear explosions are an intersting hypothesis. However, when I think 1940’s, I think World War II. Lots of explosions, smoke, dust particles. Vastly increasing industrial production globally to meet the demands of the war. Lots of ships sailing the sea in convoys belching smoke and creating contrails of their own. Ships sinking and oil burning on the sea surface belching more smoke and particulates. Aircraft flying across Europe in vast armadas generating contrails and emitting CO2 and particulates. After the 1940’s, vastly increased efforts to rebuild pulverised European cities. Could this contribute to climate changes around that time? It seems a lot of very complicated things were going on at that time geopolitically and hence environmentally. Am I the only one who thinks this way?
WW2 seems to me to offer a sort of laboratory to test all sorts of hypotheses relation to CO2 and other emissions known to have been emitted in unusually high (but assessable?) volumes for a known period of time. Yet I never see it treated in this way. Why doesn’t climate science want to talk (much) about the war?
What is the cause of the Global Mean Temperature Anomaly (GMTA) turning point from warming to plateau in the 2000s? Here is one suggestion in those emails:
http://bit.ly/eIf8M5
According to the IPCC and the above suggestion, the 1940 GMTA turning point from global warming to cooling was caused by sulfates, the 1970 GMTA turning point from cooling to warming was caused by carbon dioxide, and the 2000 GMTA turning point from warming to plateau was caused by sulfates. It is interesting to note that sulfate and carbon dioxide gave the globe a 30-year alternate cooling and warming phases from 1940 to 2000.
This is just absurd.
At this point, it seems unlikely we can do much more than indicate what combination of factors were consistent with the 1940’s bump and dip and the multidecadal mid-century flat interval, without asserting that their role has been proved. The bump and dip in the 1940’s were most likely attributable at least in part to internal climate variations involving ENSO, AMO, and PDO.
The flat interval is more significant for evaluating long term climate trends because of its much longer duration, which intervened between two multidecadal warming intervals. It ended with a resumption of warming around 1977 – Temperature Record. It seems likely that “Global Dimming resulting from an increase in anthropogenic aerosols played a significant role, and that the aerosol effect on surface insolation began to revert to Solar Brightening in the 1980s, probably complemented by a 1970’s increase in Solar Irradiance. At the same time, the PDO shifted from a negative to a positive phase at the time warming resumed, and a prominent role for this fluctuation appears plausible to the extent that the PDO was acting as an independent cause rather than partially as a Response To Climate Forcings.
I believe it is possible to suggest that almost all of the changes between 1950 and the 1980s can be explained on the basis of the above phenomena, but this by no means excludes a significant role for other variables as well.
Corrected version of one of the above links – Global Dimming
Also, the solar irradiance graph was from a blog post by Bob Tisdale.
Fred,
I think that this …
“At this point, it seems unlikely we can do much more than indicate what combination of factors were consistent with [Insert global climate parameter and period of interest here], without asserting that their role has been proved.”
… would be a fine summation of the state of climatology.
I addressed that below.
Speculatively, which is the point of my generalized statement.
I don’t dispute your right to your own opinion, JJ, but mine was mainly about the relative strength of individual negative factors that overall, balanced but did not outweigh the positive forcing from rising CO2. I wasn’t suggesting that the latter was speculative, because I don’t think it is.
Fred,
I say specualtive, because of the undemonstrated (and unnoticed) assumptions made to reach the conclusion. We are not accounting for all of the positive influences, nor all of the negative ones. And the ones we think we know, we probably have not quantified correctly. Let alone the questions regarding the mensuration of the output that these influences are supposed to be influenceing.
Fred,
What is the relative strength of CO2 15 um as compared with the spectrum of E-M wave from the Sun at the Earth’s top atmosphere, trivial or insignificant!
Despite the uncertainties surrounding the proportion to be assigned to each of the factors acting in a direction opposite to CO2 – aerosols, reduced solar irradiance, reduced surface insolation, PDO – one clearer conclusion does appear to emerge. The constellation of negative factors reduced the slope of CO2-mediated warming below its value in the absence of those factors, but did not result in an actual long term cooling. Similarly, the reduction in negative influences after 1977 increased the CO2/temperature slope beyond its unmodified value. The best estimate of the CO2/temperature relationship after 1950 is probably achieved by averaging out the entire trend since that time rather than examining individual decades within it. A long term cooling would appear to require even more powerful modifications than those operating during the last half of the century.
[Quote=Fred Molten]
one clearer conclusion does appear to emerge. The constellation of negative factors reduced the slope of CO2-mediated warming below its value in the absence of those factors, but did not result in an actual long term cooling [/Quote]
Only for those gifted with the magical spectacles (IPPC tm) to see the apparition of such conclusions .
My opinion, as a layperson whose opinion doesn’t mean a thing, the interplay of aerosols and anthropogenic CO2 emissions nicely explains the entirety of the 20 Century warming, and the 21st Century to date.
I am not too sure. There are interesting phase differences and interhemispheric differences that don’t quite match. I have just added a post.
PW
What if is something more simple like early urban warming, followed by station moves to airports outside of cities, followed by development and urbanization of the new sites?
As another layperson whose opinion matters not even to my cats, this explanation is far too pat. It is completely ad hoc.
The principal fright wig worn by the alarmist IPCC hypothesis has always been the surface instrumental record — GISS or HadCRUT or whatever — and its upslope after the mid-70s. But the 60-year PDO cycle, apparently first discovered in the late 1990s, is evident throughout the entire record. Were aerosols and sudden pollution reduction responsible for the 1880-1910 cooling and subsequent warming to 1940?
But when we eliminate this oscillation and look at the total trend, we see only an upslope of about 0.5 deg C/century — which also starts in 1850, when CO2 levels were hardly increasing at the modern rate. Moreover,
a) as Michaels pointed out two decades ago, if atmospheric CO2 is increasing exponentially and has a logarithmic effect on temperature, the result is a straight line, indicating that the 21st century temperature increase will also be around 0.5 deg C, not the 3+ deg of the IPCC horror show — even assuming that all the temperature increase was due to CO2.
b) innumerable proxy studies from both the NH and SH indicate that the Little Ice Age was, with high probability, the coldest period in the entire Holocene, silly Mann-made hockey sticks to the contrary notwithstanding. Purely as a statistical matter, one would expect a warming trend following such a period. And there is no plausible account of CO2 as a causal factor in either the onset of the LIA or its end.
So even looking at the IPCC’s iconic piece of “evidence”, the argument falls apart. The whole aerosols business is tendentious armwaving.
Of course, I expect any month now a paper to appear in New Scientist arguing that the temperature increase after 1850 was due to CO2 released by artillery during the Opium Wars and the Crimean War, whereas the cooling after 1880 was a lagged response to aerosol particulates from the Franco-Prussian War and the American Civil War…
Yes, they did atmospheric nuclear testing after the American Civil War?
>>According to the IPCC and the above suggestion, the 1940 GMTA turning point from global warming to cooling was caused by sulfates, … and the 2000 GMTA turning point from warming to plateau was caused by sulfates. <<
Looks like mother nature is a lot smarter than we are. The sulfur in coal isn't a pollutant at all. Nature placed it there so when you burned coal global temperatures wouldn't rise. Human beings, thinking they knew better, caused global warming by artificially removing sulfur from coal during the combustion process. This was done as a result of the "acid rain" scare, which of course was later found to be hugely exaggerated.
So, for a fraction of the cost of CO2 abatement, all we need to do is stop scrubbing sulfur from coal and global warming will be solved. As a bonus, the trillions of $$ that was going to pay for CO2 abatement can then be used to supply food, medicine and education to the needy with quite a bit left over.
I think the Chinese are already doing this for us.
Moreover, if we simply take the waste ash, which is alkaline, and dump it into some deeper section of ocean, we’ve also solved the (nonexistent) acidification problem.
I expect at any moment the “green” movement to start marching and demonstrating for more pollution, not less, to save the planet…
So, there it is. Coal – Nature’s perfect fuel. Cheaper than cheap. Plentiful everywhere. Self regulating with respect to both global warming and ocean acidification.
I was pricing coal the other day. $20 a ton for lignite. About the same energy as $200 worth of oil. Thinking about switching to coal and cutting my fuel bills by 90%
I guess the worrying aspect to me relates to the IPCC figure that Judy referenced. If you only look at their trend lines they are correct in saying that warming is accelerating in the last few decades. But they choose not to draw in a trend line for 1910-1940. And if one does, the trend is the same as from 1970-2000. Perhaps they would argue that this is the trend due principally to GHG increase in the first half of the century unattenuated by aerosols and that the trend in 1970+ is due to a larger GHG effect outpacing the aerosol effect. But I wonder if it all adds up. I still think that a comparison between the NH and the SH is illustrative as I presented in my post a couple of weeks ago. Given the oceanic nature of the SH and the residence time of aerosols one should find a much smaller decrease in the cooling. But one does not. So I am not convinced that there is not more at play than aerosols and GHG. And until we understand more about natural variability we will remain in a quandary. At least I will.
PW
Peter – The 1910-1940 trend reflects a prominent solar influence – Solar Influences On Climate, while the post-1977 trend probably represents a combination of strong CO2 forcing and a diminution of the aerosol effect and other negative modifiers, as I suggested above.
During that period, 1910 to 1940, CO2 is rising and consequently aerosols are rising. It seems reasonable to think the baton could be handed from solar to CO2 in an almost seamless transfer. Then aerosols became dominant during a period of time of intense warfare (WW2, Korean War Vietnam War) and atmospheric testing of nuclear weapons (Cold War:) 1940 to 1970. China GDP takes off in the mid 1990s and dampens 2000s’ temperature rise.
Brightening/ dimming/ brightening/ dimming – looks oddly like a physics-free ocean oscillation.
And now I’m done playing climate science.
For what it’s worth, airborne particles from military operations during the Korean and Vietnam wars should be way less than World War II (due to operations being confined to a much smaller geographic area and also the nature of the operations – less mass bombardment, particularly of urban areas, less mass transport of troops, planes, ships, etc.).
The nuclear tests would seem to be a more plausible idea – I’m curious to see what’s in the paper you mentioned earlier.
Gene – US bomb tonnage in the Vietnam War exceeded US Tonnage in WW2. I think that one is well supported. I found a reference that claimed US artillery fire in the Korean War exceeded that WW2, but I don’t believe it. Korea and Vietnam were hotspots of the Cold War, during which a lot of atmospheric nuclear testing was done. I got interested in this because of WW2, which was a simply gigantic combustion and oil spill event on a global scale. I do think it may have had some cooling effect, but the nukes are where the real potential lies.
No argument re: tons of bombs dropped (was aware of it – however, you’ll also note that in WW2 RAF bomber command was contributing ordnance as well, which isn’t reflected in the US tonnage) in Vietnam, but as I noted, both the Korean and Vietnames conflicts were restricted to a much tighter geographical area. Additionally, you have to take into account the composition of the targets, the difference in numbers, and the type of bombing techniques used (WW2 being carpet bombing and fire bombing of large areas by massive fleets of bombers). As for the artillery fire, it’s not out of the question (Korea having more static action than WW2), but the impacted areas would be largely rural areas. I agree that the nuclear testing probably had a much greater potential for injecting very large quantities of particulates high into the atmosphere.
Okay, my curiousity was picqued, so I did some playing on WoodForTrees. The statistical and scientific part is beyond my expertise, but it seems like WW2 was a non-event. If the cooling from particulates should take place without lag, then the NH trend should have been down since that’s the hemisphere getting the biggest pounding.
Anyone out there who knows better willing to chime in?
Atmospheric A-bomb testing got a lot of blame at the time for the weather.
Not that long ago there are a huge amount of press suggesting that North American weather was being influenced by polution from China.
How I wish for the days when things were simpler and we knew that the cause of all weather problems was virginity. All you had to do was sacrific a couple of virgins and things would go right again
The starts have to align for sulphates and co2 to dominate every 30 years.
Just unbelievable!
The stars have to align for sulphates and co2 to dominate every 30 years.
Just unbelievable!
Anthropogenic atmospheric CO2 doubled every ~33 years.
Mmmpf.
But if one looks at ERBS and ISCCP-FD all the warming is in the short wave and none in the longwave – clouds>sulphate>carbon dioxide is what the data shows. Warming in SW and cooling is LW shows cloud
Fred, if you look at Fig 7 in the paper you link to, you can assume whatever trend you want for solar forcing during the period 1910-1940. A large uncertainty, but the best looks like no trend in solar forcing over the period.
There was no overall trend, but solar irradiance increased in the 1970s from the previous decade, and this may have been part of the process counteracting a negative aerosol forcing and permitting the CO2 warming trend to re-emerge (see the discussion below with Nick Stokes).
If we have a look at the multiple regression model of Judith Lean.
http://www.agci.org/docs/lean.pdf
The net anthropogenic influences are increasing over the century – and these are as shown in the relevant IPCC spaghetti chart.
The model doesn’t handle the mid century bump very well suggesting that something else was happening as well.
The net anthropogenic forcing at the end of the century seems to be clouds instead predominantly.
Your qualitative narrative, Fred, is not supported by any data.
Peter Webster, that figure with its misleading trend lines is my favourite example of how the IPCC misleads its readers (note that the lead authors of that chapter were Jones and Trenberth). The misleading lines, mixing short and long-term trend to give the appearance of acceleration, were not there in the original drafts of the report but were inserted into the final version (though no reviewers asked for this).
Judy,
I don’t understand your argument at the 1970’s end of the period. Sulfates have short residence time, so they cause a temperature downtrend influence only in proportion to the rate of increase of concentration, not the absolute level. Because of the residence time, the natural assumption is that the concentration is proportional to the production rate. So if SO2 production levels off, the cooling effect, which had been countering AGW, ceases at that time.
As for the 1940’s effect, that seems to be, if anything, a few cool years not explained by SO2. We get such years frequently. In fact, it’s really just the years 1948-1951, esp 1950, If 1950 had been as warm as 1944, I doubt that you would be making this eyeball assessment.
I’m not sure I understand your argument, Nick. A negative influence on temperature is a function of atmospheric concentration of sulfate aerosols due to the reduced planetary albedo. Where rates of increase matter is in regard to production (to maintain an elevated concentration), but not in the concentration itself, where the absolute value is what counts.
Of course, an increase in concentration will mediate an increase in a cooling effect, but a steady high concentration can sustain a reduction in temperature, or a reduction in the rate of temperature increase from CO2 forcing. If your point is that an increasing concentration would be needed to counteract a warming effect from rising CO2, I would agree with you, but I wasn’t sure whether that was the point you were making.
Actually, as I think about this point, it makes sense to suggest that if aerosol negative forcing stopped rising in the 1970s, that would be sufficient to permit a CO2 effect to emerge, with a later reduction in aerosols enhancing the temperature rise.
Yes, that’s my argument. The GHG uptrend was balanced by an aerosol downtrend. When the latter stabilized, and GHGs kept rising, the balance failed.
Thanks. I wasn’t clear at first as to your point, but it turns out to be very important. Reduced insolation attributable to aerosols (i.e., observed under clear-sky as well as all-sky conditions) did not begin to improve until the 1980s, but all that is required for a CO2 signal to emerge is that the aerosol effect remain constant while CO2 increases. That would certainly have been possible in the 1970s.
I agree with this view. Aerosols ramped up to a new level between the 40’s and 70’s, then stayed constant. Because aerosols are short-lived, to ramp its amount up needs an acceleration in production, and to maintain it constant needs a steady production. This is unlike long-lived constituents like CO2 whose atmospheric concentration increases in proportion to production rate.
The aerosol production is mimicked closely by oil burning which also started in earnest in the 40’s, peaked with the oil crisis in the 70’s, dipped slightly and is only now returning to those levels. Gasoline for transportation is widespread, so it can affect large areas with pollution haze, making it a more effective albedo source than localized coal-burning plants, I believe.
The same would apply to an internal dynamic such as the PDO. Unless its negativity continued to increase, it could reduce temperature to a level below what otherwise would have been observed, but it should not change the upward slope of a CO2-mediated warming trend.
One imponderable in all this the possibility of long term positive feedbacks that amplify an initial downward force on temperature over more than a few years.
One has to think energy imbalance – when clouds decrease in a warm mode of the Pacific multi-decadal pattern – there is less reflected shortwave. Over time energy continues to accumulate in the oceans especially. Other elements may change to affect the net imbalance.
Pacific cloud changes are observed both in the satellite record and in surface observation.
The same applies to sulphates – double sulphates in the atmosphere and it changes the dynamic energy disequilibrium. I call it disequilibrium because – although the energy dynamic will tend towards equilibrium – the planet never stays still long enough for it to catch up.
When you think forcing think top of atmosphere energy in and energy out.
In my first reply to Nick, I meant increased planetary albedo, not reduced albedo.
OK try again –
http://www.nsf.gov/news/news_videos.jsp?cntn_id=117809&media_id=68710&org=NSF
Nick, you lost me on this one. I agree that because of the short residence time of SO2, that natural assumption is concentration is proportional to the production rate. So if the production levels off at a high level, the sulfate cooling remains at a high level; how do you get “So if SO2 production levels off, the cooling effect, which had been countering AGW, ceases at that time.”
It seems to me that the the cooling effect is maintained at the same high level.
See this paper
http://www.ocgy.ubc.ca/~yzq/books/paper5_IPCC_revised/Meehl2004_1.pdf
especially Fig 1C. You see a constant level of sulfate cooling from about 1970-2000.
Judy,
To clarify, by cooling effect I am referring back to the “downtrend influence”. To counter the effect of rising CO2, aerosols need to have an effect that, without the CO2, would produce a decreasing temperature trend. A stationary concentration, or production rate, won’t do that. If aerosols stay “levelled off” while CO2 increases, then CO2 has its full effect on temperature trend.
What would be the effect of a falling concentration or production rate?
A falling concentration, as began in the 1980s, would further steepen the slope of the CO2 warming curve. However, a constant concentration of aerosols, if accompanied by a continued rise in the concentration of CO2, would be sufficient for warming to re-emerge as an observable phenomenon.
“A stationary concentration, or production rate, won’t do that.”
Why not?
Consider time to equilibrium, let alone feedbacks.
This system is far too complex to be taken apart ad hoc.
In the first instance I would wonder about planktonic dimethyl sulphide sources. Plankton populations change with changes in nutrient rich upwelling over decades in the Pacific especially.
Secondly, as Chylek 09 observes – the sulphur meme does not explain Arctic amplification of the cooling signal. ‘However, there is no reason why aerosol induced cooling should be 9 to 13 times stronger in the Arctic compared to the global mean. A more plausible explanation might be found
in changes in ocean thermohaline circulation.’ It does suggest an understated complexity.
http://www.lanl.gov/source/orgs/ees/ees14/pdfs/09Chlylek.pdf
Post 1997 warming? Well – there is a wild card.
http://www.nsf.gov/js/video/player.swf
Cloud changes in ENSO are undeniable. Decadal changes in ENSO are obvious.
What ERBS says: http://science.larc.nasa.gov/ceres/STM/2004-03/wong_decadal.pdf
So aerosol cooling is as trustworthy as CO2 AGW!
The early solar data is based on isotopes and sun spots, there is almost no data on natural sulphate emissions, sulphate cloud effects are practically unknown, natural cloud changes are practically unknown, black carbon is practically unknown. If you look at the level of scientific understanding on the IPCC net forcing figure – there is very little certainty anywhere.
Funny thing is – the satellite says it was clouds between 1984 and 1999 that caused most global warming.
This would need top be looked at in the context of all aeorsols and water vapor to be meaningful. “Tis true that we have had few volcanic eruptions, mnay fewer than average, over recent decades and that has increased atmospheric clarity and that DOES account for at least 0.2 degrees of the current warming.
This is my first post here. Thanks for the opportunity to make a contribution.
First, let’s get the observational data in place. I refer to 2 meter air temperature from NCEP/NCAR Reanalysis for the equator to latitude 60°north and the equator to latitude 60°south, most of the habitable areas of the globe thereby accounted for. If I could refer to energy stored in the oceans, the chief repository of energy from the sun, I would.
From 1940 to 1978 the northern hemisphere cooled and the cooling was strongest in winter. From 1978 through to 2007 the northern hemisphere warmed mainly in winter.
The experience in the southern hemisphere was just the opposite. The southern hemisphere warmed strongly from 1940 through to 1978, temperature peaked in the mid nineteen-eighties and that peak has not been exceeded since.
AGW proponents never let the facts get in the way of a religious celebration. They are very good tellers of sophisticated stories.
Why did surface temperature change in this way? If it were due to aerosols or carbon dioxide and other greenhouse gases we would not observe this striking difference between the hemispheres.
The evolution of northern hemisphere temperature relates to the Arctic Oscillation with strong polar atmospheric pressure from 1940-1978 and weak thereafter. When polar pressure is high the cold polar easterlies sweep the continents in winter. When polar pressure is low the warm south westerly’s have free reign.
In the southern hemisphere a weak polar stratospheric vortex after 1948 is associated with a strong increase in stratospheric temperatures, the most extreme increase in stratospheric temperature found at the highest latitude and at the highest elevation. There is a zone of very low pressure that surrounds the Antarctic at 60-70° south that, because of its tendency for constant variation in atmospheric pressure, has excited attention and it has come to be known as the southern annular mode.
The Antarctic polar circulation is a coupled circulation because air temperature decreases with elevation all the way to 10hpa. This promotes convection throughout the atmospheric column, a phenomenon usually associated with just the troposphere. The Antarctic circulation promotes the descent of cold stratospheric air into the troposphere at 60-70° south. Ozone absorbs long wave radiation from the Earth, warms the air and raises geopotential heights from the surface to the mesosphere centered on this same latitude, 60-70°south.
The increased temperature of the Antarctic stratosphere after 1948 reflects its enhanced ozone content. The churning of extra ozone into the troposphere has promoted a continuous decline in atmospheric pressure between about 50° south latitude and the South Pole since 1948, but that process, swiftest at the start seems now to have come to an end.
It may be observed that as the surface pressure falls at 60-70° south, the temperature of the sea increases between that latitude and the equator, the variation in sea surface temperature being more at higher and less at lower latitudes.
The ozone that descends into the troposphere at 60-70°south follows the spatial pattern of the southern annular mode. This same pattern appears in the sea surface temperature anomalies with a distinct south east to north west orientation of increased sea surface temperature as if that ozone were being carried via the counter westerly’s at higher altitudes. It appears that it is the higher altitude cloud made up of highly reflective ice particles that is affected.
What drives the change in polar pressure? That is a story for another day.
Congratulations. You have an explanation for one piece of the mother nature’s puzzles. I am looking forward to your details of “What drives the change in polar pressure?”.
From an energy account perspective, what is/are the effect(s) on the Earth (atmosphere, ocean, in particular) from your paragraph:
“The ozone that descends into the troposphere at 60-70°south follows the spatial pattern of the southern annular mode. This same pattern appears in the sea surface temperature anomalies with a distinct south east to north west orientation of increased sea surface temperature as if that ozone were being carried via the counter westerly’s at higher altitudes. It appears that it is the higher altitude cloud made up of highly reflective ice particles that is affected.”
From the energy account perspective:
Sea surface temperature depends in the first instance on incident radiation and in the second on the rate of evaporation. Evaporation strongly affects surface temperature, less so the temperature of the waters beneath.
In the southern hemisphere the differential pressure driving the prevailing westerly winds of the mid latitudes has increased continuously over the period of record. This increases surface area and drives evaporation. So, the sea surface temperature response to ‘ozone churn’ into the troposphere is muted. The response in the northern hemisphere is quite spectacular by comparison because the northern hemisphere lacks a deep low pressure trough outside the Arctic circle of the sort that occurs in the southern hemisphere. Consequently the differential pressure driving the westerlies in the northern hemisphere is weak by comparison. There has not been a secular increase in the pressure differential in the northern hemsiphere.
Add to this the fact that the coupled stratosphere/troposphere circulation in the north is an intermittent, winter only activity with a deterministic relation to the direction of the prevailing wind and you see why the surface temperature response in the northern waters is very strong. When surface atmospheric pressure falls at 50-60°north, in the pattern of the northern annular mode, sea surface temperature rises in the mid latitudes. It’s a short rope.
So, the temperature of the surface in the north is a better guide to what is happening to the input side of the ocean energy budget, the only budget that really matters.
But of course, most of the ocean is in the south and it is here that the big energy deposits occur.
When you are looking at the output side consider the rate of evaporation from the tropical ocean. A good indicator is the increase in temperature of the tropical atmosphere at 850hPa where low cloud is formed.
The surface temperature is a function of energy in and energy out. The record of outgoing long wave radiation indicates that there has been a continuous increase in outward long wave. So, we really need to explain the strong increase in energy coming in. The variation in ozone content of the stratosphere is the key to that. Primarily it depends upon the interaction between the mesosphere and the stratosphere via the night jet.
The historical record tells the story much better than any model of mans invention.
I never know what to make of Erl. All of it is without evidence but with gleams of inspiration.
Different temperature in different hemispheres on decades is an impossibility – as seems to be shown in the CRU surface temps –
http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif
Ozone warming by UV is without doubt something that drives long term drift in the polar vortices – see for instance http://iopscience.iop.org/1748-9326/5/3/034008/fulltext – It may indeed drive ENSO but the direct energy implications are minor.
UV drift might have an effect on the Southern Annular Mode – which is an index of sea level pressure. Positive is by convention lower pressure at higher latitudes.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-3-32.html
Other than that – be wary of strong claims and evidence free rants from either side.
Chief Hydrologist:
‘All of it is without evidence’. That is a tone I dislike. It is not easy to provide the data to support a complex argument in a forum such as this. You will simply have to wait.
‘Different temperature in different hemispheres on decades is an impossibility”.
Wrong. That is precisely the point that brought me into this discussion. Better check the data from the reanalysis data-set. Here is the source. http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl
All you have to do is plot the annual data.
And if one hemisphere warms while the other cools and then the former stays the same while the other warms you will probably agree that we can cross out aerosols and greenhouse gases as agents of change. I thought that anyone would catch that drift. Plainly I was mistaken.
We do need to have proper regard for the data gentlemen.
“Ozone warming by UV is without doubt something that drives long term drift in the polar vortices – see for instance http://iopscience.iop.org/1748-9326/5/3/034008/fulltext – It may indeed drive ENSO but the direct energy implications are minor. ”
No. The polar vortex, and here I must be precise, for I am referring to the night jet that bridges the mesosphere and the stratosphere, is more or less active according to the status of polar surface atmospheric pressure. When pressure falls, the stratosphere between 100hPa and 1hPa warms with peak warming at 2hPa. This is due to a diminution in the flow of odd nitrogen compounds from the mesosphere. The immediate consequence is an increase in stratospheric ozone and a rise in temperature. No direct solar radiation of any description impinges on the polar upper atmosphere in the middle of winter. Warming is due entirely to the interception of outgoing long wave by ozone. Look here for the current situation: http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/
The concentration of odd nitrogens (nitrogen oxides) in the mesosphere varies with solar activity.
The northern vortex impacts surface pressure on the margins of the Arctic Circle mainly in winter. Mostly, and always when the Arctic Oscillation is high the troposphere and the stratosphere are not coupled circulations in the Arctic.
The southern vortex is continuously influential and the strength of the circulation is such that a near permanent zone of very much lower atmospheric pressure appears over the oceans on the margins of Antarctica. A global minimum in fact.
The southern annular mode is not driven by ‘UV drift’. It is driven by shifts in the mass of the atmosphere affecting surface pressure, the night jet and stratospheric ozone concentration as described above. The decline in pressure at the margins of the Arctic and Antarctic circles, and its variability over time, is a function of the number of molecules of ozone that enter the troposphere. The coupled circulation seems to spin ozone and warm air to the periphery where geopotential height increases are observed from the surface all the way to the mesosphere.
The circulation is coupled because at high latitudes temperature falls all the way from the surface to 10hPa.
But I am indebted to you for the opportunity to clarify what I have written above. And I thank you for your foray into the unknown.
Yes, I am making strong claims. These are new ideas. And I need a little time to make sure they are well expressed. Got to make a living and currently it’s a busy time for me. Hobbies fit in as and when it is possible.
Any explanation of climate change must have due regard to the difference in the rate and direction of temperature change between the hemsipheres and between the seasons. This is fundamental. Talking of ‘global temperature’ and singular sources of change affecting the globe as a whole is a waste of time and an irritation in the extreme.
You were not meant to like it – you were meant to provide evidence. I am over people with mad ideas and overweening confidence and arrogance. You were talking about SH temps peaking – what was it – mid 70’s.
First of all I linked one of the recognised temperature time series – http://www.cru.uea.ac.uk/cru/data/temperature/ – that shows global, SH and NH temps. Here is an Australian record – http://www.bom.gov.au/climate/change/amtemp.shtml –
Does your record say something different? You have somewhat of a problem here and I would suggest that playing with the NCEP/NCAR plot page may have some limitations.
I merely suggested by reference to a recent study that solar UV influenced the polar vortices – http://iopscience.iop.org/1748-9326/5/3/034008/fulltext – ‘There is growing evidence that dynamical coupling across the tropopause means that stratospheric changes can influence the underlying troposphere [6, 8] and under some circumstances, robust tropospheric responses are indeed predicted by models. Tropospheric jet streams have been predicted to be sensitive to the solar forcing of the stratosphere [9, 10]. This could occur through disturbances to the stratospheric polar vortex [11] which are observed to propagate downwards to affect the tropospheric jets.’ The reference was to the Arctic Polar Vortex – but it works as well in the SH.
No strong claims – just deliberate and measured analysis.
Chief Hydrologist
I like your tone even less.
Here is the data:
http://climatechange1.files.wordpress.com/2011/02/surfacetemp.jpg
http://climatechange1.files.wordpress.com/2011/02/nh-sat-0-60n.jpg
http://climatechange1.files.wordpress.com/2011/02/sh-sat-to-60s.jpg
When Lockwood et al say this:
” The effects on climate of solar variations have been shown to be swamped by anthropogenic effects in recent decades on global scales .”
They, like you, have quite obviously not considered the course of surface temperature recorded in that graph.
When Lockwood et al write this:
” Models (e.g., [16]) do predict that perturbations can descend from the stratosphere to the surface by altering the propagation of planetary waves coming up from the surface.”
and cite this:
At http://www.agu.org/pubs/crossref/1999/1999JD900445.shtml
“Baldwin and Dunkerton: The midwinter correlation between the 90-day low-pass-filtered 10-hPa anomaly and the 1000-hPa anomaly exceeds 0.65 when the surface anomaly time series is lagged by about three weeks. The tropospheric signature of the AO anomaly is characterized by substantial changes to the storm tracks and strength of the midtropospheric flow, especially over the North Atlantic and Europe. The implications of large stratospheric anomalies as precursors to changes in tropospheric weather patterns are discussed.”
Perhaps Lockwood et al have in mind some mechanism whereby the planetary wave can propagate backwards in time to affect the interaction between the mesosphere and the stratosphere via the night jet some three weeks earlier.
So – you refer to models as evidence – and offer them up to me again this time graphed on a website. On this basis you reject the instrumental temperature record – the most basic of time series?
You then go on to build a very odd straw man argument about planetary waves moving backwoods in time. There is nothing that is certain in this topic. The suggestion of Lockwood is one amongst a number of potential pathways – it was one that emerged from a model. I would suggest, however, that there is a difference between planetary waves propagating from the surface to the stratosphere and surface storm tracks spinning off the polar front.
I like your theories even less. ‘And hey, those graphs tell a grosso story. We don’t have to argue about whether the NCEP/NCAR reanalysis is a valid representation of the real world when the differences in the trends pre and post 1978 are so obvious.’ There are many changes to Earth’s climate post 1976/77 – but these do not include cooling in either the NH or SH.
You are so busy obfuscating – and refuse to accept that this is a basic misconception of stunning proportions. I don’t hope to cure you of this – I simply point to the the incongruity of the argument lest others be tempted to give credence to the climatological musings of a somelier.
Chief,
You say:
“There are many changes to Earth’s climate post 1976/77 – but these do not include cooling in either the NH or SH. ”
You are attributing something to me that I never wrote. I have not suggested that either hemisphere cooled post 1976/1977/1978. What I wrote in my first post was this:
The southern hemisphere warmed strongly from 1940 through to 1978, temperature peaked in the mid nineteen-eighties and that peak has not been exceeded since. That is true if you look at annual data. See: http://climatechange1.files.wordpress.com/2011/02/surfacetemp.jpg
If you look at monthly data the peak in southern hemisphere the two meter air temperature anomaly (between the equator and 60°south) occurred in December 1973. See: http://climatechange1.files.wordpress.com/2011/02/sh-sat-to-60s.jpg
The data that I prepared is indeed presented on a website and so is this conversation. That in itself does not invalidate the data or the conversation. I downloaded that data and prepared the graphs myself, at your insistence. Perhaps you should do the same and then, should you discover an error, you can tell me about it.
Later I had this to say:
“And if one hemisphere warms while the other cools and then the former stays the same while the other warms you will probably agree that we can cross out aerosols and greenhouse gases as agents of change. I thought that anyone would catch that drift. Plainly I was mistaken.”
So, if you have any integrity at all you might like to retract the comment about cooling post 1976 and also, while you are at it, this bit of bluster:
“Different temperature in different hemispheres on decades is an impossibility”.
I am delighted that you have come in so strongly on this point. It’s a big help in establishing the fact of the matter. When people acknowledge that temperature within a hemisphere can move quite differently to temperature in the alternate hemisphere they will stop talking about ‘global temperature’, see the foolishness of attributing climate change to aerosols and greenhouse gases (that are common to both hemispheres) and look harder, for influences that are particular to an individual hemisphere.
And that is where a study of the annular modes, what drives them, the relationship to clouds and surface temperature that plainly exists, will make a lot more sense than the sort of nonsense that passes for climate science today.
You are playing at semantics –
me
“There are many changes to Earth’s climate post 1976/77 – but these do not include cooling in either the NH or SH. ”
you
‘You are attributing something to me that I never wrote. I have not suggested that either hemisphere cooled post 1976/1977/1978.
you
“And if one hemisphere warms while the other cools and then the former stays the same while the other warms you will probably agree that we can cross out aerosols and greenhouse gases as agents of change. I thought that anyone would catch that drift. Plainly I was mistaken.”
The SH cooling is simply not real – http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif – that you persist in this a problem that you alone need to address.
Let’s get this right. My data relates to the latitudes between the equator and 60 degrees of latitude. Your CRU data relates to the entire hemisphere and the globe.
It is the northern hemisphere that cooled and it did so between 1948 and 1978. It cooled at all latitudes, not just equator to 60° north. After 1978 it warmed strongly at all latitudes.
There is no evidence of southern hemisphere cooling at any time between 1948 and today and that comment relates to that part between the equator and 60°south. But neither has it warmed at all since 1978 in that same zone between the equator and 60° south. The warming occurred prior to 1978 contemporaneously with the cooling of the northern hemisphere.
The CRU data suggests that the entire southern hemisphere warmed after 1978. Looking at the reanalysis data for the zone 60-90°south we see a decline in maxima and an increase in minima with the latter having a steeper rise than the fall in the maxima. So the mean temperature rose. I make the point that no humans live in this zone. The change in the temperature is not a Big Deal. With the annual minimum at minus 25°C and the maximum at minus 5°C you can understand why no one lives there.
In the northern hemisphere the part of the globe that lies north of 60° north currently experiences an average winter minimum of minus 25°C and a summer maximum of 8°C with an increase in both of about 2.5°C since 1948. Its still a pretty miserable prospect so far as the prospect for human habitation is concerned and I imagine that real estate is dirt/ice cheap.
You persist in suggesting that I have said that the southern hemisphere has cooled, and that it is ‘my problem’. The ‘problem’ is in your erroneous perception of what I have written. You accuse me of obfuscation. I do apologize if my expression has been less than transparent.
If there is a problem here it is in your inability to conduct a civil discourse. Its the mark of a man who is both antagonistic and confused.
Rather than strike out in an insulting fashion why not just ask a question.
If you think the ideas are rubbish why not do the civil thing and just ignore them?
‘From 1940 to 1978 the northern hemisphere cooled and the cooling was strongest in winter. From 1978 through to 2007 the northern hemisphere warmed mainly in winter.
The experience in the southern hemisphere was just the opposite. The southern hemisphere warmed strongly from 1940 through to 1978, temperature peaked in the mid nineteen-eighties and that peak has not been exceeded since.’
It is unmitigated nonsense. Admit it to yourself and move on. You wriggle, you reinvent your comments freely as you go, you dissemble , you misdirect, you malign my motives, integrity and intellect – these are all less than admirable traits and I have no patience for them.
The statement quoted above from your original post is nonsense and I make no apologies for such mildly robust comment. This was my response – http://judithcurry.com/2011/02/16/mid-20th-century-global-warming-part-ii/#comment-43990 –
Here is my second reply – http://judithcurry.com/2011/02/16/mid-20th-century-global-warming-part-ii/#comment-44281 –
A little bit more insistent that temps in both hemisphperes and globally peaked in the 1998 El Nino.
Here is my third reply – http://judithcurry.com/2011/02/16/mid-20th-century-global-warming-part-ii/#comment-44281 –
It contains nothing but quotes and an insistence that surface temp.. well why bother.
Sir, it is not I who, in your words, am uncivil, antagonistic and confused. I have simply challenged the arrant nonsense of your opening statement. Not for the purpose of correcting you – I take that to be impossible. My purpose was to advise others to question and reject such glib and misguided narratives as yours.
Are we done yet – because this is growing exceedingly tedious?
Erl & Chief,
Cool down. You both have a piece of the puzzles and I enjoy both of your explanations of your piece of the puzzles. Hostile attitudes do not contribute to any discussion. Let the readers enjoy your knowledge not your hostility, please.
Sam NC,
There was a simple proposition made – the ‘experience in the southern hemisphere was just the opposite. The southern hemisphere warmed strongly from 1940 through to 1978, temperature peaked in the mid nineteen-eighties and that peak has not been exceeded since.’
Now this is obviously incorrect – but was defended using words like uncivil, antagonistic and confused. These were not my words – I simply quoted them.
It is a troubling issue – what to do with theorists who have some emotional attachment to their theories but which are more of a flight of fancy than grounded in any reality that can and has been measured adequately.
Nothing wrong with flights of fancy – here is what I said originally. ‘I never know what to make of Erl. All of it is without evidence but with gleams of inspiration.’ And went on dispute the SH cooling statement.
The problem arises – http://judithcurry.com/2011/02/18/epistemology-of-disagreement/#comment-44588 – because of ‘close mindedness’ on both sides I believe. How to shake that up is the vexing question – how to circumvent the human need for certainty? How to convince people that living with uncertainty is the logical path? Was I successful in this at any time with anyone? Perhaps I should try electro-shock therapy?
My own view is that we don’t know nearly enough to put a coherent picture together. The error bounds and the unknowns are so large – it is an absurdity (perpetrated by both sides) to think they have.
I am sympathetic to the idea that – ipso facto – changing the composition of the Earth’s atmosphere is not something we should continue in a conscious way and ‘spatio-temporal chaos’ and uncertainty do not dissuade me.
What are the solutions? I was amused by a report released yesterday by an Australian industry body – they want a carbon tax because the alternatives are costing us a damn sight more. But it is not a solution unless unless we have technologies that can provide another source of energy supply. The other solution is in meeting and exceeding Millennium Development Goal commitments. Far from hand waving, as this was unkindly characterised here by a Bart who shall remain unidentified, this is the critical issue for humanity and for the piffling problem of greenhouse gas emissions.
Cheers
Robert
Chief Hydrologist
Chief,
My reference is plain. Here it is:
“First, let’s get the observational data in place. I refer to 2 meter air temperature from NCEP/NCAR Reanalysis for the equator to latitude 60°north and the equator to latitude 60°south, most of the habitable areas of the globe thereby accounted for.”
And that was the data I provided.
You are talking about the hemisphere as a whole and using that data to try and invalidate what I say.
A simple case of apples and oranges.
There was a simple proposition made – the ‘experience in the southern hemisphere was just the opposite. The southern hemisphere warmed strongly from 1940 through to 1978, temperature peaked in the mid nineteen-eighties and that peak has not been exceeded since.’
I responded to your statement – which is obviously incorrect. Perhaps you would like to recast your arguments about sulphates. Along the lines of, according to the NCEP/NCAR model – the temperatures trends 60 degrees north and south of the equator invalidate the sulphate forcing explanation of the 40’s to 70’s global temperature blip? I don’t think this helps your argument at all.
You are still trying to confuse the argument by shifting grounds. I went back to NCEP/NCAR and replotted for 0 to -90 degrees. It still shows a peak in the mid 1980’s. I would suggest a problem with the model rather than it being reliable data – whether it is apples or oranges.
erlhapp says:
erlhapp, you start by saying you are going to use observational data. Then you say you are referring to the climate model output reanalysis … but that’s not data. That’s the output of a climate model constrained by observational data. It is not observational data in any sense of the word. The NCAR reanalysis is valuable, but please don’t mistake it for data.
w.
Hi Willis,
Your point is well made.
But, if I were to restrict myself to observational data I could not fly at all. The point is, there is just not enough of it. Some is miss-recorded. Some is from uncalibrated instruments and when you look at the record there are many periods where observers went on holiday. And, there are so few observers in so very many places.
I place my faith in a careful and consistent analysis of the relationship between numerous variables used as a cross check on the status of every single sparse observational detail.
It’s the only way to go.
As we get to know the behavior of the atmosphere over time that computer program will get better and better.
And hey, those graphs tell a grosso story. We don’t have to argue about whether the NCEP/NCAR reanalysis is a valid representation of the real world when the differences in the trends pre and post 1978 are so obvious.
Hooray.
At least one or two climate scientists acknowledge that the IPCC delusion whereby every little wiggle in the global mean temperature is ‘explained’ as a result of some (usually man-made) ‘forcing’ is misguided. See the spatio-temporal chaos thread.
Just a side story around SOx:
In the 80’s there were large some forest damage devastation in Northeastern Finland. The majority of the forest are either spruce or pine, and most of the damaged are were above the polar circle. Anyway, the Russian activities in the Murmask region and particularily in Nickel were pointed out as the reason for the damages – acid rain, you see.
An urban legend has been told from later 80’s: In a related research conference the issue presented to a Russian scientist, obviously very carefully as this was politically a rather delicate issue at the time. Not surprisingly, he dismissed this stubid idea. His justification was (after laughs), that the permanent wind direction (with few exceptions) is from West to East, not vice versa, hence it would be very strange if the pollution – mainly SOx, dust, soot – managed to travel against the wind.
Later it was found out, that the forest damages were not caused by acid rain at all, but overherding of reindeers and a few cold winters with low snow cover which had damaged the trees. This of course didn’t have the same attention from media as the acid rain alternative.
Just wondering whether this story with CO2 and warming turns out to be something similar.
Is it possible to estimate (i.e. measure) the effects of aerosols from satellite based LW/SW radiation spectras, or is the primary reason for their proposed cooling effect more or less based on cloud seeding?0
Here is one source – Aerosols (see in particular chapter 2), although it may tell you more than you want to know.
Thanks very much Fred for the pointer, exactly the kind of study I was looking for. Seems that the Chapter 2 deals with the issues I was interested in; apparently there are several ways to assess the radiative part (i.e. absorbtion, scattering) whereas the cloud formation issue is more complicated.
Can someone talk about the elephant in the room?
I mean, bump is nice and all, even though it only appears north of the tropics, and ought have some attempt at an explanation, and could help understanding, and so forth..
But the temperature is still at global record levels, has been for over a decade, and this measure even on the really awful dataset used for this purpose is way above the error bars when compared to temperatures before the bump.
Acceleration? Variation? Who cares.
It’s high now.
It’s somewhat lastingly high in appearance.
All the rest is detail, unless high is explained, and just asserting that sometime in the millennia before we could use thermometers to track sorta kinda we might speculate when last it was high doesn’t cut it to a skeptic.
Asserting natural variability also doesn’t cut it, when the cyclic phenomena of oceans all have a period less than half the extant record and do not reflect in the data a signal that indicates the cycle will return low again.
Apply logic on the scale of the data that accounts for the data.
Anything else is bafflegab.
“But the temperature is still at global record levels, has been for over a decade, and this measure even on the really awful dataset used for this purpose is way above the error bars when compared to temperatures before the bump.”
Yes, CO2 can absorb 15 um IR energy and able to heat up the atmosphere is way above errror bars by a trillion times. CO2 and other greehouse gases can have 324 W/m2 back radiation is also at a trillion times blownup. Why there is no magnitude sense amongst the Climate group of people is beyond me.
Sam NC
Nice way to meet a question about an elephant with an answer about some gree gas houses.
People in gree gas houses shouldn’t throw stones, you mean?
So. Elephant. Room. Logic that addresses the particular elephant in the particular room, not that addresses somebody else’s mouse in somebody else’s gree or pin or blu house, if you will.
Because like all of our typing has become on the WordPress editing window, your answer is too truncated and a little askew.
Nice catch on typos and thats best Climate group of people can do and unable to get the sense of magnitudes. Good job, Bart!
Sam NC
If we made WordPress about typos, we’d all be doomed.
By all means, if you wish to tackle the problems of estimation, scope, scale and magnitude, do so.
Here’s the optical magnitude of CO2 in the all the miles between the ground and the top of the atmosphere: one pencil per square inch. That’s not only the approximate weight equivalent between the graphite in one standard pencil and the extra CO2 per square inch of sky added every decade, but also the approximate additional shading in the 1-to-30 non-overlapping, non-saturating band of IR per inch of sky every decade from human CO2 emission.
Whatever calculations you use, or believe, or have had told you must be true, about heat and how it works, you do not present anything like the magnitude of that pencil every square inch in underlining how much the magnitude of optics is being affected cumulatively now at a rate of every ten years.
See, I don’t see your calculations worked out. I don’t know what validation you’ve used. I know and can show what it takes to find the almost half-gram of graphite figure per square inch, I know and can show where the Gtons of carbon emitted by humans is estimated. I can take a pad of paper and a pencil and a ruler and look at one square inch shaded by a pencil until the pencil is worn out and see that impact.
You have some math someone else tells you works.
I trust my pencil over you.
WordPress. 1-to-30 micrometer band.
Gah!
Bart,
“So, we’re all agreed we’re not talking about “red hot CO2″ then, and can drop the specific heat digression entirely as completely irrelevant?”
No. Specific heat capacity applys to all conditions involving absorption/emission of energy which result in a change of temperature.
Bart,
“What is typically called the 15 micrometer band resolves into three separate spikes for CO2 at 2.5, 4.0 and 20 micrometers,”
Thats news. How do you measure that. All I have seen from the spectrometer record from that warmists paper (I can’t remember that paper) that CO2 has only around 14 – 16um wavelengths.
On the same paper right above the spectrometer record was the H2O spectrometer record with spikes all over the whole spectrum (actually within the same range of CO2 record).
“So, there’s a paper you rely on that exploits one quarter of the facts to draw a conclusion by ignoring 75% of the facts. How surprising is that?”
No. You made this thing up. I said the whole spectrum of H2O IR radiation as compared with CO2’s narrow band of 14-16 um wavelengths. How come H2O has just one spike at 16.5um, when the H2O has the whole spectrum of the spectrometer records?
“As for the much greater importance of water, CO2 has found a place to stand and a lever long enough to move that water higher.” No. CO2 has no place when compared with H2O’s spectrum of IR radiation.
“If water weren’t so close to its critical temperature range for becoming vapor, then we could pump CO2 into the air until the cows came home and died of acidosis. ” Its that water at the critical temeperature range distinguish from the rest of the planets in the universe by absorbing a huge amount of the solar radiation and evaporate with huge amount of latent heat and gradually release IR during the night.
“H2O by happy accident loves the little temperature range we live in, and CO2 has the power to make it shoot through the sky, quite literally.” No. CO2 has no such power, no such mechanism to do it. With abundance of water on the Earth, it regulates the Earth’s temepratures from extremes so that habitable to human beings, plants and animals. Again CO2 a feeble weak gas with 15um IR spikes has nothing to do with any temeprature at all.
Bart,
“Here’s the optical magnitude of CO2 in the all the miles between the ground and the top of the atmosphere: one pencil per square inch. That’s not only the approximate weight equivalent between the graphite in one standard pencil and the extra CO2 per square inch of sky added every decade, but also the approximate additional shading in the 1-to-30 non-overlapping, non-saturating band of IR per inch of sky every decade from human CO2 emission.”
“Pencil per square inch” thats is not science neither engineering terms. I prefer to use mass in kg or lbs, energy terms J or BTU or rate of power W or BTU/h or heat flux W/m2. Use them if you can.
“That’s not only the approximate weight equivalent between the graphite in one standard pencil and the extra CO2 per square inch of sky added every decade, but also the approximate additional shading in the 1-to-30 non-overlapping, non-saturating band of IR per inch of sky every decade from human CO2 emission.” Very unscientific, use your standard terms from what you learn from your education, don’t mess around. If you are unable to use standard scientific terms to describe your concept about magnitude of 15um CO2 IR energy here, with respect to the whole E-M wave spectrum, IR radiation from the Earth surface, the back radiation from the GHG, you fail to grasp any energy concept at all like many of those who claim themselves to be scientists here.
Bart,
Have you ever tried to calculate the mass of CO2 in the atmosphere, say, 390ppm? Do you know the physical properties of CO2, say, specific capacitiy of CO2 gas in the atmosphere? What is the proportion of 324 W/m2 back radiation CO2 has? Do you trust or ever queried there were 324 W/m2 IR back radiation? 324 W/m2 is almost as good as the heat flux of the Sun’s incoming radiation 342 W/m2 at the Earth’s top atmosphere and largely greater than the Earth surface’s absorbed 168 W/m2 incoming radiation, if you assumed that Kiehl & Trenberth data are correct. Assuming the atmosphere has absorbed the incoming solar radiation of 67 W/m2 is correct, how come GHG have 324 W/m2 back radiation? These data are as good as anyone’s guesses.
Use your energy terms, and get real!
Sam NC
Yes, I have done the calculations.
Please see my reply to Willis Eschenbach below.
No, I trust no one, including Kiehl & Trenberth, unchecked.
As Willis Eschenbach was kind enough to check my figures in detail and with rigor, one expects the same of those who distrust — or trust — Kiehl & Trenberth.
My analogy merely confirms that there could be something large happening based on optical properties by visually illustrating what the data means.
One pencil per square inch of sky every 10 years.
Boggling that anyone would dare call this trace.
Bart,
0.039% CO2 is trace (15um IR energy) because it is relative to atmospheric heat contents (absorb solar radiation and then emit complete spectrum of IR from the Earth surface, evaporation of water, water vapor with almost complete spectrum of IR in the atmosphere).
I was a bit occupied and have not yet read your calculations. I will comment in below accordingly.
Bart,
I read part of your calculation and Willis’. At 1st, I was struggling to figure out the physical meaning of CO2 in kg/m2. I think I can assume it is partial pressure of CO2 gas exerted on the Earth surface. OK, fine, the mass of CO2 is proportional to the partial pressure of CO2. So here is my calculation:
At STP conditions, atmospheric pressure is 101.25kPa at sea level.
CO2 has a molecular weight of 44, and air molecular weight is 29.
Partial pressure due to CO2=101.25x1000x0.00039x 44/29=59.9N/m2 or 6.11kg/m2
CO2 increase per decade is 15ppm, i.e. 15×6.11/390=0.235kg/m2=0.152g/in2/decade.
So, Willis’ calculation is correct.
Now your pencil case, I am struggling with the meaning of it. Is it relevant? How do you correlate the CO2 pressure with your pencil mass?
How do you compare when the Earth’s IR radiation going thru CO2’s additional 15ppm/decade, i.e. thru the additional pressure of 0.152g/in2 and when the Earth’s IR radiation going thru with the total atmospheric pressure of 101.25kPa.
Here is the comparison at sea level:
101.25kPa= 101250N/m2 or equivalent of 10321.1kg/m2, compared with CO2’s 390ppm of 6.11kg/m2 or compared with addition of CO2’s 15ppm addition per decade of 0.235kg/m2.
The comparison of magnitudes of the Earth surface’s IR whole spectrum radiation with the CO2’s 15um wavelength and some other CO2’s minor wavelengths of radiation. Since water vapor (assuming 1% in the atmosphere) can absorb the whole spectrum of IR radiated from the Earth surface as compared with CO2’s (0.039%) a few wavelengths of radiation. CO2 can at most absorb 0.039% of the Earth’ IR radiation at 15 um. H2O and CO2 can at best absorb 1.039% of the Earth surface IR radiation at 15um, H2O can absorb at most 1% other than 15 um wavelengths, the rest of the Earth surface IR energy (99%) just go straight through the atmosphere at the speed of light. Also, that CO2’s 15um IR radiation absorbed is re-emitted within the second of absorption.
From the Kiehl & Trenberth (K&T) Earth’s Annual Global Mean Energy Budget (1997), assuming the incoming solar radiation of 168 W/m2 is absorbed by the Earth surface and the Earth’s surface water evaporation of 78 W/m2 (latent heat of evaporation that contributed to the 1% of water vapor in the atmosphere) are correct, then the maximum full spectrum of IR radiation from the Earth surface is 90 W/m2. Water vapor in the atmosphere only absorbs 0.9W/m2 if assumed the whole IR radiation spectrum is absorbed. Suppose CO2 can absorb the whole spectrum of IR radiation from the Earth’s surface, CO2 only absorbed 0.00039×90 W/m2=0.035 W/m2 and the direct solar absorption of 0.00039×67 W/m2=0.0261 W/m2. Approaching zero when only 15um is efficiently absorbed as compared with the whole spectrum of the IR radiation from the Earth’s surface. The magnitude of CO2’s contribution to the atmosphere warming is trivial. So where did the K&T’s 324 W/m2 back radiation come from?
Sam NC,
Your calculation of the CO2 absorption or the absorption of water vapor has no basis in physics. Therefore it’s result has neither anything to do with the strength of absorption.
The 324 W/m^2 comes from a correct calculation.
What are your calculations that has physics basis? Let me and the readers have some comments of your calculation. Without your calculations, you are not contributing to the discussion at all. Waiting patiencely, regards.
You think that 324 W/m2 from a correct calculation, let me see your calculations and provide my comments and other readers’ comments.
And you may ask, where is the error?
That I cannot answer, because I have not the faintest idea, why you think that your calculation might give a reasonable answer.
You may also ask, what is the right calculation. For that I can only refer you to reasonable sources. Most accessible might be ScienceOfDoom. Some earlier threads of this site discuss the issue as well, but finding the answer from them may require a larger effort.
Pekka,
A reply without substantiation is non-contributing. I can refer you the physical properties of CO2, H2O. I can refer you to photons, reflection, absorption, deflection, push back with meaningful expalnations.
I can advise you its not science of doom, its non-science of doom in the climate community not climate ‘science’ community. The whole climate community is just non-science, non-physics, 324W/m2 back radiation!
Yes you can refer where ever you wish. There is only one difference. My reference works, if you care to study it.
It is up to you.
Typical Cimate Community weak comments and concepts?
Sam NC (and to some extent Pekka)
Ah.
The weight component of my analogy was not intended by me to be the working element, but only a method for me to work out the optical density of CO2 in air and its changes per decade.
I will come back to weight and partial pressure soon.
In most of science, one hopes for the useful precept that gives us a means in our minds and in our symbolic logic to resolve questions as yet unsatisfied.
Up to turning to thinking about not the IR as heat (a clumsy thought anyway) but the IR as light, my precepts were vague and confused and unsatisfied.
Light, however, I am somewhat familiar with through optics and just plain ability to see.
Project a three-dimensional problem to a two-dimensional one, if you can do it meaningfully and remember you are manipulating your framework as you move forward, and you have achieved a powerful form of simplification.
This simplification does work for transmissivity in air, within narrow parameters. (And in some ways for the less relevant optical density, but only as a boundary condition.)
Whether you have your CO2 in a pure form and compressed to many atmospheres, or free in air from ground to sky, there’s a similarity* in the transmissivity based on the total amount of CO2.
*Would that I had a decent reference to link to, but I don’t.
So, weight of CO2 (ie mass) over area is a meaningful expression of transmissivity, and one even a simpleton like me can calculate.
This projection from two dimensions to three is, of course, not the whole story, as we must remember.
However, change in transmissivity is very real in terms of meaning to heat.
If IR isn’t transmitted, something happens to heat until IR is transmitted.
We know this pretty well, unless we believe in Perpetual Motion or disbelieve in photons.
Now we have to move back from two dimensions to three again.
Anyone could note that I don’t talk about the 2.3×10^-4 +/1 0.5×10^-4 natural CO2 levels before the Industrial Revolution, or about the occlusion up to the end of the present decade, when discussing the change of the current decade.
This is because of two things.
A) CO2 absorbtivity is non-saturating. However much IR in its waveband is absorbed, there remains more absorbtion capacity in CO2.
B) Air is three-dimensional, and so changes in transmissivity as a property of light through that one dimension we had earlier dropped, the height of atmosphere, will not be made much less important by prior condition.
Take my 1″ square of pencil-darkened paper. Cut it into a hundred smaller squares, and position them evenly across your 8.5″x11″ page, and you will be able to start to imagine why. Overlap a page like this with all the pages in the pencil, and you will see that each additional page still has a dramatic effect, no matter how dramatic the previous effect had been.
Cut those hundred squares into a hundred smaller, and repeat, down to the size of a molecule.
So it can be seen that prior condition is a minor consideration overall, for change in heat due to change in transmissivity due to change in concentration of CO2.
These are the facts, set in pencil.
Now, as to weight, it is important, and you could with sufficient experiment and calculation, proof and time, arrive to the same conclusions eventually as this method, but it is the long way around, and relies on so much as yet undeveloped or poorly-specified science as to be nearly just as useless as the conventional approach was when it was pioneered over a century ago, one believes. Why reinvent something no better?
Errata
For ‘optical density’ in third sentence, please substitute ‘transmissivity’. Was thinking of how smoke detectors work, which is inapplicable.
For the figure, ‘2.3×10^-4 +/1 0.5×10^-4’ please correct to ‘2.3×10^-4 +/- 0.5×10^-4’.
Bart,
I agree fully that the mass of CO2 in a column of air is a significant number in determining the absorption of IR by CO2. In several threads the smallness of this mass has, however, been totally erroneously been used as evidence against the significant influence that CO2 has on the surface temperature. These people do not realize, how little CO2 is needed for strong absorption at wavelengths with the strongest absorption and how even a very small amount of CO2 can transfer very efficiently the absorbed energy to N2 and O2 (and those who have understood these parts may err on the point of saturation, which does not happen more than what the approximate logarithmic law implies)
The random calculations that have been used to prove totally false conclusions are clearly not your fault, but they have appeared here repeatedly – and of course always without any explanation of some of the erroneous steps as everybody would be confronted by the impossibility of justifying these steps when trying to do that.
Bart,
“A) CO2 absorbtivity is non-saturating. However much IR in its waveband is absorbed, there remains more absorbtion capacity in CO2.”
Can you proof CO2 absorptivity non-saturating? It has specific heat capacities (0.846kJ/kgK at 300K, 0.791kJ/kgK at 250K). Can you elaborate “more absorption capacity in CO2 scientifically?
B) Air is three-dimensional, and so changes in transmissivity as a property of light through that one dimension we had earlier dropped, the height of atmosphere, will not be made much less important by prior condition.”
What are you trying to say? Light changes its transmissivity thru altitudes or atmospheric pressures? You need to do a calculation to verify your point.
Bart,
I still don’t see your pencil and paper example relevant. You need to actually do a calculation of your transmissivity rather providing a description of what were doing with the pencil & paper and linked it to your definition of transmissivity. You know CO2 is transparent not opague, right?
Sam NC
Why do you give the heat capacity of CO2? How do you think that it affects the result (it does not affect in reality)?
The non-saturability of the absorption is due to the fact that there are weaker absorption lines at the edge of the strong absorption. When the stronger lines saturate, the weaker start to have an effect. This combination leads to the approximate logarithmic law. The precise form does not have any deep meaning, but numerical calculations show that the logarithmic law is closely followed at all concentrations that anybody can imagine for the earth atmosphere.
I have also difficulties in understanding the second point, but I do not think that it is so important.
A) Specific heat is a limiting factor on absorbtivity?
That would require some expansion and development, as otherwise ‘specific heat’ of CO2 seems at first blush as relevant to optics as flavor of CO2 or sound of CO2.
To allow me to familiarize myself with the basics of your claim, link, please?
For non-saturating, please look at Figure 5 here: (http://www.wag.caltech.edu/home/jang/genchem/infrared.htm) or also Figure 10.1 here: (http://www.heliosat3.de/e-learning/radiative-transfer/rt1/AT622_section10.pdf)
You can see the spikes of CO2 compared to the level of overall absorbtivity to be extreme, covering the whole or almost the whole height of the graph.
It may be more precise to say CO2 is practically non-saturating, and almost no matter how much radiation is absorbed, CO2 has remaining capacity to absorb more, or to simply say at the outset that we’re speaking with regard to the amount of IR in the context of our discussion.
If we were talking about CO2 in the corona of the Sun, we’d see its absorption limits exceeded.
For a spectroscopist doing routine analyses, the saturation level of CO2 is generally assumed unlimited because it is so high in its specific bands.
I adopted the conventional usage of these specialists, not of those unwilling or unable to familiarize themselves with the basics of a topic before commenting on it.
B) No. I’m trying to say the opposite of what you’ve read.
Changes due to change in mass of CO2 are relatively insensitive to either the level of current concentration or to prior level of concentration.
There is some decrease in effect, and indeed it is logarithmic, but at current concentrations it could be treated as linear with very little error in the calculation.
Do the experiment, and see for yourself what it looks like.
Everyone can afford a pencil.
Sam NC
At one point, to be very self-flattering, I was flattered to be called a good math teacher.
I worked with those who others called unteachable, and had given up on. Most of my students thought this of themselves.
I succeeded by first reminding them what their eyes and ears and kinestheses already knew.
“You need to actually do a calculation of your transmissivity rather providing a description of what were doing with the pencil & paper and linked it to your definition of transmissivity. You know CO2 is transparent not opague, right?”
If you cannot believe your eyes, what calculation could possibly move you?
CO2 is indeed extraordinarily opaque within its own IR bands, in a section of the bandwidth where no other component of air is opaque, in that significant and powerful IR window left open by water vapor.
CO2 is as opaque to IR as pencil is to visible light.
As an experiment, you know pencil is transparent, too? Drawn on a sheet of glass instead of paper, what looks like thick and even grey on paper is barely a smudge that transmits a good deal of light.
Which is why you have to flip page after page after page filling in one inch squares until you exhaust your pencil, and then line them up, to see this effect.
I recommend onionskin, but you can use ordinary paper with enough backlight to get a pretty good impression, until the opacity of the paper creates too much noise for the experiment.
The ideal would be to use glass, but that’s a lot of glass and I wouldn’t want to be liable for people dropping it and injuring themselves.*
*Also don’t want to be held liable for paper cuts or splinters from pencils.
Bart & Pekka,
The specific heat of CO2 is introduced because there is a limit that CO2 can absorb energy as opposed to non -saturating. At 275K, the energy 0.791 kJ absorbed by 1kg of CO2 will increase the CO2 by 1K. There is a limit that the CO2 can absorb energy. I suppose CO2 never gets red hot in the atmosphere and there is also a time frame limit for CO2 to hold that energy within a second, its absorbed energy re-emitted. No saturation at all!
Sam NC
So, we’re all agreed we’re not talking about “red hot CO2” then, and can drop the specific heat digression entirely as completely irrelevant?
And we’re agreed that as part of the mechanism of back radiation, that some of the energy is re-radiated by the CO2, and again that’s entirely irrelevant all-in-all, too, since that’s a thermodynamic issue and this is an optics discussion?
So, any relevant questions?
Sam NC,
The specific heat of CO2 is totally irrelevant. Its significance is equal to the share of CO2 of the atmospheric gases. It represents linear motion and rotations of the CO2 molecules, but the IR absorbed by CO2 is not directly connected to these motions of the CO2 molecules. They are equally connected to the linear motion and rotations of N2 and O2 molecules, because the energy of the vibrational states of CO2 is released in collisions with these other molecules. The only specific heat that is relevant is that of all molecules of air.
One more explanation.
When a 10 um photon hits a CO2 molecule it may get absorbed and lead to an oscillating molecule, which has the absorbed energy as energy of oscillation. 99.9% (or 99.99%) of these oscillating molecules release the extra energy in milliseconds in a collision with a N2 or O2 molecule. The energy is then split between kinetic energy of linear motion and rotational energy of the two colliding molecules, which have further collisions with other molecules again in milliseconds. This way all the absorbed energy is distributed to thermal motion in local air.
When CO2 molecules collide with other molecules the transition between vibrations and no vibrations goes also in the other direction. Therefore a few percents (perhaps 5%) of the CO2 molecules are at any moment in a vibrational state capable of emitting 15 um IR. Again 99.9% of them do not emit, but release the energy in a collision, but few percents of all CO2 molecules is enough to produce also strong IR emission at 15 um from the small fraction that ends up releasing its energy this way.
SamNC, where are you getting all your misinformation from? Is there a Web site, or are you just making it up? If it is a Web site, you need to go back and tell them
a) H2O absorbs in limited bands like CO2
b) heat capacity has nothing to do with radiation absorption
c) CO2 can absorb everything at 15 microns within a few tens of meters of atmosphere, and has a significant effect from 16-18 microns.
d) The CO2 fraction of atmospheric molecules has nothing to do with what fraction it absorbs. It acts independently.
e) These are just for starters. I don’t have the patience to go into others until you confirm you understand these ones, otherwise it is a waste of time.
Jim D,
a) you are correct that H20 has limited bands of absorption but it has way huge bandwidth than CO2 that makes CO2’s absorption of 15-18um dwarf.
b) any energy absorb by gas molecules will have to take specific capacity into consideration. Thats the physical properties of a gas. The climate community try to ignore it because all AGW or GHG theory do not hold water in front of specific heat capacities of gases.
c) even 15 – 18um for CO2 is insignificant as compared with H2O’s huge bandwidth of absorptions.
d) thats what scientist call the climate community non-scientific.
a)The importance is that CO2 dominates at 14-16 microns where H2O has no effect.
b) The heat capacity of air is dominated by the other gases. The CO2 absorbed energy is quickly distributed among them.
c) No, see (a).
d) OK, I’ll restate it. IR only interacts with CO2 and H2O and other GHGs. Their fraction relative to O2 and N2 is irrelevant for radiation absorption, but the total heat capacity (mostly O2 and N2) is what determines the heating rate.
Jim,
a) No. H2O at 14-16um IR absorption is as signicant if not much more due to abundance of H2O over CO2 mass ratio. I cannot remember which warmist paper shown all spectrums of CO2 and H2O IR radiation absorption.
b) I agree that “The heat capacity of air is dominated by the other gases.” So the CO2 absorbed energy is not significant to distribute to other gases, if not trivial consider only 14~16um band of IR radiation absorption against the huge bandwidth of H2O.
d) So you think CO2, H2O and other GHG are selective with 15um IR radiation and energy only flow amongst themselves? IR radiation energy amongst these GHG molecules do not pass thru at the speed of light to the outer space, sticking together? Did you not just said CO2 absorbed energy is quickly distributed among other gases.
Sam NC
a) Part of the problem here is some sloppy language.
What is typically called the 15 micrometer band resolves into three separate spikes for CO2 at 2.5, 4.0 and 20 micrometers, with a fourth (H2O) spike at 16.5 micrometers of no greater significance than the other three (slightly less than each of the lower two bands, as shorter wavelength translates to higher energy).
Which is why I refer to CO2’s non-overlapping spectrum.
So, there’s a paper you rely on that exploits one quarter of the facts to draw a conclusion by ignoring 75% of the facts. How surprising is that?
As for the much greater importance of water, CO2 has found a place to stand and a lever long enough to move that water higher.
If water weren’t so close to its critical temperature range for becoming vapor, then we could pump CO2 into the air until the cows came home and died of acidosis.
H2O by happy accident loves the little temperature range we live in, and CO2 has the power to make it shoot through the sky, quite literally. Hence positive feedback.
SamNC
a) In terms of radiating to space, CO2 dominates at the top of the atmosphere, so what you see at 14-16 microns is CO2 emission. This is what helps to determine the earth’s energy budget. Near the surface even with water vapor, CO2 has a big effect in dry areas and polar regions.
b) CO2 contributes 20% of the greenhouse effect, and water vapor contributes the rest in clear conditions. Since 150 W/m2 less is emitted to space, than is emitted from the surface, I would not call it a small effect.
d) Are you having trouble understanding that absorbed energy is distributed through all the air molecules in local thermal equilibrium?
Jim D,
“a) In terms of radiating to space, CO2 dominates at the top of the atmosphere, so what you see at 14-16 microns is CO2 emission.”
Assume you are right here, CO2 molecules at TOA is almost nothing compared with the space it occupied. 99.999% of IR radiation just pass right thru at the speed of light. Don’t just blowup the importance of CO2 by trillions of times but that just the problem of the Climate Community.
” This is what helps to determine the earth’s energy budget. ” CO2 has no place with its 15um as against the whole spectrum of the Earth surface’s IR radiation.
“Near the surface even with water vapor, CO2 has a big effect in dry areas and polar regions.” CO2’s 15um has trivial effect in these areas, as explained and calculated.
“b) CO2 contributes 20% of the greenhouse effect, and water vapor contributes the rest in clear conditions.” I have not yet seen your calculations. I would love to see it and put my comments on the calculation. Remember to put you assumptions down for me and the readers to comment.
“Since 150 W/m2 less is emitted to space, than is emitted from the surface, I would not call it a small effect.”
Where did you get that 150 W/m2 less? Its not even from the K&T’s Energy Budget (1997).
“d) Are you having trouble understanding that absorbed energy is distributed through all the air molecules in local thermal equilibrium?”
No. Apparently, you cannot put forward your contradictions in your statements and resort to me “having trouble understanding ” to divert attention. Go back and read my reply and response accordingly if you have any real explanations.
Sam NC
This picture is one of my favorites in explaining, how important CO2 is
http://en.wikipedia.org/wiki/File:ModtranRadiativeForcingDoubleCO2.png
This is a model calculation and I do not refer to it as a precise description of the real atmosphere, but it explains very well the basic mechanism.
The Earth warms, when radiation cannot escape freely from the warm layers of the atmosphere or the even warmer surface. When radiation can escape only from the uppermost cold layers the effect is at its strongest. From this picture you can see that this happens most influentially in the wavenumber range 600-750 cm^-1. This fact is totally due to the strong absorption of CO2 even at the low density of the uppermost troposphere. Water is the dominant factor at almost all other wavenumbers, but it is as efficient only at lowest wavenumbers that carry little energy anyway.
The picture tells also, how additional CO2 modifies the result, but that is not may main point here.
Drawing the picture as it is drawn here is illuminating in the way that equal area corresponds here always to equal radiative energy. The dip produced by CO2 is very important indeed.
SamNC,
1. You keep referring to the whole spectrum, not realizing that the spectrum variations from the black body are completely due to GHGs, of which CO2 contributes 20% (Schmidt et al. 2010, JGR). This paper has been pointed out before. MODTRAN is also a good tool for investigating this yourself for individual atmospheric profiles.
2. At the Antarctic surface, measurements show CO2 contributes 1/3 of the downward radiation.
3. 150 W/m2 is about what you get from subtracting 240 W/m2 IR going out at the top from 390 IR coming out of earth at the bottom of those diagrams.
4. Your previous statement (d) made no sense to me at all. What sticks together? Why does the speed of light matter?
Jim D,
“1. You keep referring to the whole spectrum, not realizing that the spectrum variations from the black body are completely due to GHGs, of which CO2 contributes 20% (Schmidt et al. 2010, JGR). This paper has been pointed out before. MODTRAN is also a good tool for investigating this yourself for individual atmospheric profiles.”
Sorry you have no proof of that 20% contribution due to CO2.
“2. At the Antarctic surface, measurements show CO2 contributes 1/3 of the downward radiation.”
Really?
“3. 150 W/m2 is about what you get from subtracting 240 W/m2 IR going out at the top from 390 IR coming out of earth at the bottom of those diagrams.”
You need to validate 324 W/m2 before you come to 390W/m2. 324 W/m2 is non-sense unless you can prove it exist.
“4. Your previous statement (d) made no sense to me at all. What sticks together?”
Because lack of you are contradicting your statements.
“Why does the speed of light matter?” So you don’t know IR radiation travel at the speed of light emerged out of space atmosphere in less than a second? CO2 can only absorb a trace amount of the Earth surface’s 15um IR radiation and 15um is just a minute portion of the whole Earth surfaceis Complete spectrum of IR radiation. You seem unable to understand these simple facts.
SamNC,
You don’t even accept the 324 W/m2 back radiation, which puts you in the Dragonslayer category. Amazing. I had thought you were in a category where there was still hope. I don’t think it is worth pursuing this conversation unless you have a specific question about something you think you don’t know. Anyway, I have given you facts and numbers, and you prefer to ignore them without showing counterproofs, and just repeating questions in circles. The 15 micron and spectrum answer is already given above.
The large share of the CO2 band can be seen in the Figure 3 (red curve of the left picture) of this article
http://eospso.gsfc.nasa.gov/ftp_docs/validation/airsStatusReport_WaldenEtAl.pdf
CO2 dominates the broad maximum between 600 and 750 cm^-1.
Bart R | February 17, 2011 at 7:49 pm | Reply
Bart, thanks for the numbers. Here’s what I get:
Weight of carbon in 1 ppmv of atmospheric CO2 = 2.18 gigatonnes/ppmv
Weight of CO2 in 1 ppmv of atmospheric CO2 = 8 gt/ppmv
CO2 increase in a decade ≈ 15 ppmv
CO2 weight increase in a decade = 120 gigatonnes
Global surface area = 5.11E14 m2
CO2 weight increase per decade per square inch = 0.15 grams/in2/decade
Now, pencil leads. Density of graphite is about 1.6 g/cc. An 8″ pencil with a one eighth inch lead has about 2.6 grams of lead in it.
So I get the change at about a twentieth of a pencil lead per square inch per decade … or about a twentieth of what you say.
Now, I could have made an error, please check my math. Unfortunately, I can’t check yours. This is curious because you say:
Um … well … what I can say about that is:
w.
PS – The ” approximate additional shading in the 1-to-30 [micrometer] non-overlapping, non-saturating band of IR ” goes up by the log of the CO2, not directly with CO2 amount as you say above …
PPS – If you sit there and “look at one square inch shaded by a pencil until the pencil is worn out and see that impact,” you’ll find that the impact is to turn the paper totally, completely black. Are you claiming that a 15 ppmv increase in the CO2 turns the atmosphere opaque to CO2? If not … then of what use is your “a pencil can turn an inch of paper jet black” example?
Willis Eschenbach
Thank you, sir.
You took up the challenge of a skeptic admirably, and I agree with your approach and conclusions, given the sketchy nature of my claims as set out in this topic.
My old pencil case:
http://judithcurry.com/2011/02/04/slaying-a-greenhouse-dragon-part-iii-discussion/#comment-38635
“..in the past 15 years approximately 1×10^14 kgs additional anthropogenic carbon (did I do that right, just over 95 Gtons C from CO2 and other GHGs?) spread over over 5×10^14 m2 (or 5.1×10^8 km2?) is 200 grams of additional carbon IR light must travel through to get from the surface to space every square meter?
0.02 grams of additional carbon per square centimeter?”
http://judithcurry.com/2011/02/04/slaying-a-greenhouse-dragon-part-iii-discussion/#comment-38756
http://judithcurry.com/2011/02/10/spatio-temporal-chaos/#comment-42174
Your shiny new one:
Shocking, one can come up with almost an inch of pencil worth of carbon in CO2 in every square inch of sky, even by your method, no?
But to bridge your figures and mine somewhat.
a) I was going with weight of CO2, not of Carbon in CO2, for the reason that it is CO2 that has the optical effect, and it isn’t practical to treat Carbon separately from its molecule. The weight of the molecule is roughly 44 parts per 12 parts of Carbon, reducing our disparity from approximately 1/20th of an 8″ pencil to 1/7th, in round figures.
Still, barely an inch of pencil is — though technically remaining a pencil — not very honest of me, if this were what I meant to say. Which it wasn’t.
However, either way, almost a half inch or over an inch per square inch of sky per decade!!
How coulds this not shock one?
b) You use 1/8″ for the diameter of the lead; I used 2 mm. Did you work out the mass from the 1/8″ figure or did you look it up? I found conflicting references so, again, approximated from the volume of a cylinder.
This diameter difference would get us from about 1″+ of pencil to about the length of a quite stubby golf pencil, very roughly.
Which would again be a bit of a cheat, if it were what I meant.
c) You appear to assume graphite pencils are pure graphite, which you must understand is an absurdity; pencil leads are clay-graphite mixtures for obvious reasons of the mechanical properties of graphite.
Either way, this takes us from a golf pencil, allowing for standard dilution in a #2 pencil to a full 8″ pencil, at a very rough approximation.
It seems like a bit of a cheat when seen through your objective and skeptical lens to leave out the obscure fact that pencil leads — while not lead, also aren’t even one quarter pure graphite too, and I will going forward make explicity clear what I mean in this regard.
By the way, many standard pencils are seven and a quarter inches long, excluding the eraser*.
*Yes, I understand many cultures don’t put erasers on pencils.
Otherwise, your math and discussion appear sterling, and I am flattered you have treated my scandalously sketchy presentation so seriously.
Other vagueries of mine,
d) I treat the current decade as the one starting now, based on best future projections, as the number and type of emissions one expects in the next decade can be fairly reasoned to be increasing and at a reliably predictable order of magnitude.
This makes my pencil now slightly longer than yours, I think?
But then, a lot of people see length through bias, so it remains too much to speculate whose is longer.
e) I allowed for loss due to sharpening the pencil to obtain a usable tip.
f) It’s an analogy, and pencils vary widely.
That’s the pencil.
Now to the paper.
Elsewhere, I argued, “CO2 may be described as IR-opaque because it demonstrably produces bands in the IR range (non-saturating, non-overlapping with other atmospheric elements at approximately 2.5, 4 and 20 micrometers) when measuring absorbtivity.”
Per your PPS, leaving aside that on paper flat on the desk, one is looking at one type of optical property, looking at onionskin held up to the light one is looking at another, and discussing back radiation one is deeply mired in something altogether other than these, very few pencils produce jet black.
The standard pencil produces grey in an even application on the surface of a single sheet, and this grey is quite visibly transmissive — for a single sheet when looked through against a strong light. It’s also very reflective, too, again in the visual range.
A single sheet represents a slice of sky, varying in thickness depending where one starts.. though all of them very thick slices in sky, compared to the thickness of that surface they are projected onto for the purposes of this analogy.
Stack enough paper together, however, and the eye will convey in the visual range a startling and — forgive the expression — graphic image of the effect corollary in the IR bands.
PS Conveniently, when stacking paper in this way, the visual impact _also_ goes up by something approximating the logarithmic pattern based on the number of sheets of pencil scribble, just like with CO2 in air.
How impressive is that, for an analogy to accomplish?
Now, there are other considerations, because a projection from three dimensions to two does not fully capture all optical properties.
There are issues a photographer would speak to as depth-of-field, and asterism, and too many details to go into, also which I will not pretend to sufficient expertise in.
However.. my pencil stands.
Be shocked.
Be awed.
Find it undeniable.
But whatever you do, don’t dare claim at this late date to be suddenly alarmed.
Erratum
Can’t blame WordPress for this one.
Please replace “almost an inch” with “almost half an inch” in Shocking, one can come up with almost an inch of pencil worth of carbon in CO2 in every square inch of sky, even by your method, no?
Bart R,
The oceanic cycles are less than half of what record?
In what way is the record a record hig or non-trivial?
And according to whom?
hunter
Thank you for seeking clarification, that’s admirable considering how unclear I can sometimes be.
The length of the record.
In time.
Measured by most as years.
For example, 160 years or sixteen decades (approximately) is a length cited for the length of the temperature record.
Not, in contrast, the record temperature being discussed, which would be in degrees, not years, and which would make less sense to talk about halves of (though I can see based on your apparent perception of my past record you might believe the least sensible possible interpretation would be the one I intended).
The length of the the various significant three-letter-oscillations (TLO) according in several past topics to our host, Dr. Curry, appear to top out at six decades more or less.
Six being less than half of sixteen.
While there do appear to be multi-decadal trends in rise and drop of temperature within the temperature record, even to the point where one might suggest two almost complete cycles prior to the current cycle and with not-dissimilar length in decades and maximum and minimum temperatures in degrees..
But we’re way above the peak temperature of these previous two cycles — which not necessarily meaningful in and of itself, given so little data — and we’re in some sort of seeming plateau at that level of temperature.. again, not extremely meaninful in and of itself given so little data.
However, the height and duration of the plateau are not only not explained by the usual suspects, they fly amply in the face of most of them in most ways (ocean cycles, sun cycles, etc.), and have no really great explanation of their own by most skeptical assessment.
Hence elephant.
Brad R: The trouble with sorting out the elephant in the room is finding the footprints. It may well be that the last decade has been somewhat warm, it may be that temperatures have been drifting up for 100+ years and CO2 emissions have been going up as well. But as a 50:50 skeptic – and no doubt a bear of little brain – I like to sort out problem to my own satisfaction which in this case means going to the data and seeing what that says.
Ex-ante modelling is fine if a real elephant is indubitably there, stomping around, leaving its statistical footprints all over the place. Now I hate econometric methods so what I have been through over the last few months has been rather painful and deserving of considerable sympathy. But having downloaded the data, run regressions, varied the lag windows, tried multi-period lagged models, fiddled with log conversions, worried over unit roots and even checked that I have the dependent and independent variables the right way round I cannot obtain any relationship between annual % variation in CO2 and annual % change in temperature.
That has always been the key question for me: can variability in temperature changes be explained by the variability in CO2 emissions? It is the same sort of problem as trying to identify what component of security risk can be explained by the volatility of any one of a number of market or macro-economic variables. It is in essence an issue of what is driving temperature volatility.
Using data from 1886 forward my R2’s are persistently close to zero no matter how I run the regressions. Indeed, my results seem to closely fit with those of Soares, P.C., (2010), Warming Power of CO2 and H2O: Correlations with Temperature Changes, International Journal of Geosciences, 2010, 1, 102-112. So until I can find out where I and presumably Soares are going wrong then attributing causes to shorter time periods or netting off aerosol effects against soot, PDO’s, or changes in solar irradiation etc takes 2nd place and is not very interesting until I can nail the elephant.
Ps: I know that IJG is probably regarded by the cognoscenti as a rubbish journal but at least the author of that paper and his peer reviewers are making the same mistakes as me. That is some comfort.
Bo Bryan
I appreciate your situation.
And if any of that very impressive chore of analyses were appropriate or meaningful to the question I’d asked, I’d even sympathize.
See, I didn’t say CO2 is the elephant.
I said there’s an elephant.
I’m not all that concerned with tracking it to CO2 (if I knew where it led, why would I waste time tracking?), but with tracking it at all.
I have a problem with CO2 as CO2 in and of itself, and don’t really see the point of correlating it to all possible connections before finding it a problem, or proving harm, or proving effect.
CO2 levels are changing, and I’m pretty sure your analyses would — again, for something that isn’t the elephant I asked about — find better correlation between human CO2 emissions and CO2 levels, once seasonal and regional variation were accounted for.
This change proves in and of itself that the resource is not infinite, therefore is limited, therefore economically ought be treated as a scarce resource, therefore emission of CO2 ought be priced and the revenues returned to its stakeholders (everyone with a stake in air) or we face the free rider problem and must acknowledge we’re being systematically stolen from by those who gain most benefit of emitting CO2.
See, _that_ elephant in that other room, I’ve got a pretty good picture of.
This elephant is heat, and it’s heat bigger than the mid-20th-century bump, and it’s sustained heat, and it doesn’t appear to be explained by anything; this spontaneous elephant of immaculate conception is a problem, an unaccounted for deviation.
Two different elephants; I’m only asking about one of them here.
If you need to seek the connection, that’s great. I love puzzles too.
But substituting the one for the other doesn’t help me.
If you happen to address the melting Arctic sea ice elephant too, that’d be great, but still different.
<>
You are going about it all wrong. Take your numbers over to RC and they’ll straighten you out. CO is going up, temperature is going up. 100 % correlation. Mann will help you out. Once you have your data, try different statistical techniques until you get the result you want.
Can Mann prove that back radiation is 324 W/m2? Can Mann calculate how much total IR energy absorb by total mass of CO2 at 15 um in atmosphere? Can you?
Some scientists have approached this issue from the direction of global dimming/brightening. The multitude of estimates of these processes is mind-boggling, see this review
http://www.leif.org/EOS/2008JD011470.pdf
But this does suggest that the changes over the 1940-1970 and 1970-now periods are much more similar than are suggested by the anthropogenic aerosol estimates. Looking at all the numbers (and there are a lot) it looks like the global brightening could be 2/3 the magnitude of the dimming phase. Based on this approach if like skeptical science you’re going to attribute ~0.6oC of cooling to aerosols in the 1940-1970 then you have to start thinking about attributing something like 0.4oC of warming to brightening (essentiually aerosols) in the recent warming phase.
This issue is confusing to me, hopefully a reflection of the uncertainty in the science rather than just my dim-wittedness.
Does anybody want to take up the issues raised by global dimming/brightening estimates by people like Wild and Ohmura and how they compare to the science based on estimates of anthropogenic emissions?
This paper seems to confirm what I’m saying, at least over Europe anyway.
http://www.outsidethebeltway.com/library/Aerosols-Global-Warming-Study-2008.pdf
“if like skeptical science you’re going to attribute ~0.6oC of cooling to aerosols in the 1940-1970 then you have to start thinking about attributing something like 0.4oC of warming to brightening (essentiually aerosols) in the recent warming phase.”
That is probably roughly accurate. It implies that the slope of temperature between 1950 and1977 should be shifted from flat to rising, and that the slope from 1977 to 2000 should be reduced (after 2000, there appears to be a renewal of “dimming”). The result of the adjustments would come closer to a line drawn between 1950 and 2000 temperatures, signifying a fairly constant warming, than to a pronounced difference between the two intervals.
Fred,
“That is probably roughly accurate. It implies that the slope of temperature between 1950 and1977 should be shifted from flat to rising, and that the slope from 1977 to 2000 should be reduced (after 2000, there appears to be a renewal of “dimming”). The result of the adjustments would come closer to a line drawn between 1950 and 2000 temperatures, signifying a fairly constant warming, than to a pronounced difference between the two intervals.”
Can you suggest a theory that support your statements above?
“if like skeptical science you’re going to attribute ~0.6oC of cooling to aerosols in the 1940-1970 then you have to start thinking about attributing something like 0.4oC of warming to brightening (essentiually aerosols) in the recent warming phase.”
‘That is probably roughly accurate.’ (FM)
The really amusing conclusion is that, with 0.4 degree C sulphide contribution in the warming to 1998 (according to Fred), a 0.1 degree solar contribution – warming from carbon dioxide was 0.1 degree C
Not worth worrying about then?
Chief,
Yes, I would not worry about both the aerosols and the CO2 as their masses in the atmosphere are insignificant to cause any temperature effects in the atmosphere. The reasons being the energies reflected, absorbed, radiated respectively by aerols and CO2 are trivial as compared with the incoming solar radiation energy, the Earth’s absorbed energy, evaporation energy and the Earth’s IR radiation . 0.1, 0.4, 0.6 deg C are all guesses without any energy magnitude senses and non-scientifics, non-physics, in particular, non-physical properties of any substances on the Earth and the atmosphere included.
I was not being serious. I think it is evident that climate is a ‘spatio-temporal chaotic system. The system is sensitively dependent on small initial changes. Could there be abrupt and nonlinear as a result? It is not predictable.
Thanks ferd for the helpful guidance – I knew there must be a simple solution, ask the people at RC. Trouble is I know, and I guess you know too, that temperature drift and CO2 emissions are rather nasty unstable stochastic variables. When I do my sums I get an R2 of 0.77 (same with ocean temperature v CO2) – means nothing though. Level 1 econometrics.
ps: I’m a great admirer of MM’s temperature reconstruction work although I wouldn’t have let a student of mine get away with his centering and backfilling methods. Just picky really.
I fail to understand how the climate science community fail to acknowledge the global mean temperature anomaly pattern shown in the following chart.
http://bit.ly/ePQnJj
Dr curry, do you acknowledge this pattern?
This amplitude of 0.3 degrees is only a tenth that of doubling CO2. Seems irrelevant to the problems of the next century.
Hi Bart R (sorry about the misnaming, just woken up, cleaned the muck off the laptop and spotted you are not Brad R) – now I suspect you and I are in significant agreement. Net reduction in CO2 emission has to be a primary objective if we want a sustainable future. No doubt about it. But as T S Elliot said the greatest treason is to do the right thing for the wrong reason. If the CO2 fingerprint is not there in the longest data run we have then we are faced with three possibilities: there is no impact, negative natural feedback mechanisms effectively quench its effect or other anthropogenic causes are in play. As I see this debate it’s about the third of these possibilities.
However, the more direct answer to your problem may be in the data. If you take the temperature data run from 1880 forward, calculate the annual % change in temperature and then run a volatility window (10 years works well) you see something rather interesting. Temperature volatility fell off a cliff in the ten year period centered around 1978 (rephasing the window suggest it happened post ’78) and has reverted to its preindustrial level and below. What that suggests to me is that what drove temperature volatility in the period centred around 1920 – 1978 is no longer a factor. The only significant lurch back in those years where temperature volatility fell back to the pre 1920 norm is centered around 1942. Temperatures may be high over the last two decades but with very low variability. What this suggest to me is that aerosols severely destabilized temperatures but that the underlying warming drift is not down to CO2. Running the volatility window for CO2 alongside confirms what the regression shows. You are looking at two quite different processes that whilst moving in the same general direction are unlikely to be causally linked. So for the last decade: the elephant’s there but its not moving.
Bob Ryan
Had I realised how many Barts were in residence and prominent members of the community, I might have ended up Brad, with no regrets.
I don’t dispute your analysis entirely, lacking the times and means to either properly agree with or disagree with your proposal, and regret that I have such weak things to say about it yet one way or another.
I suggest it is premature to say this idea has sufficiently good support to be confident in it at this point so far as I can see.
Your development is, however, worlds better than for example those of Claes or of Girma, trusting to further examination of the evidence, in my opinion.
And yet, this stability comes at a time when I’m told by sun-lookers and ocean-watchers that stability is entirely unexpected.
How many Nina’s and Nino’s have there been in this stable period?
How many significant solar variations?
In roughly the same period, the Arctic and Antarctic icecaps have been behaving — so far as we can tell — very strangely.
One hardly ever expects a string of unrelated large extreme events to coincide to stability.
So, I have to remain skeptical while such objections are unaddressed.. The multiplying villainies of Nature do swarm upon this temperature plateau and.. it’s still there. That’s some elephant.
I have been a bit provocative here – mea culpa – just having fun. All these considerations are fun but we still have most people treating a spatio-temporal chaotic system as a linear system where elements are added to produce a definable and easily predictable effect.
In principle changes are sensitively dependent on small initial changes and abrupt change is nonlinear. While past change can be seen in the energy record – future change is unpredictable within what we currently understand. A bit of intellectual humility people. Chaos and ignorance are two things at least to be borne in mind as regards future climate risk .
Chief Hydrologist
The climate (global mean temperature) is not chaotic. Actually, it has a cyclic pattern shown in the following chart for the data of the CRU:
http://bit.ly/ePQnJj
This chart shows the following periods for relative global cooling and warming phases:
1. 30-years of global cooling from 1880 to 1910
2. 30-years of global warming from 1910 to 1940
3. 30-years of global cooling from 1940 to 1970
4. 30-years of global warming from 1970 to 2000
If this pattern that was valid for 120 years is assumed to be valid for the next 20 years, it is reasonable to predict:
5. 30-years of global cooling from 2000 to 2030
There is no such things as cycles – it is chaotic bifurcation in ocean/climate states. You need to look at the ocean causes of these changes in surface temperature. A 10 to 30 cooling is indeed possible – although these abrupt climate climate changes are not predictable.
One of the peculiar attributes of complex discussions,is the ability to overlook the obvious ie the elephant.
If we examine the SH record especially mid latitude stations where the T record is peturbed mostly by Canards and Black swans on the devils staircase eg WMO 2010
New analyses of both satellite and radiosonde data give increased confidence in changes in stratospheric temperatures between 1980 and 2009. The global-mean lower stratosphere cooled by 1–2 K and the upper stratosphere cooled by 4–6 K between 1980 and 1995. There have been no significant long-term trends in global-mean lower stratospheric temperatures since about 1995. The global-mean lower-stratospheric cooling did not occur linearly but was manifested as downward steps in temperature in the early 1980s and the early 1990s. The cooling of the lower stratosphere includes the tropics and is not limited to extratropical regions as previously thought.
As statospheric peturbation seems to be the main driver of climate dynamics in the SH eg WMO 2010,Polvani 2011.
ABSTRACT
The importance of stratospheric ozone depletion on the atmospheric circulation of the troposphere is studied with an atmospheric general circulation model, the Community Atmospheric Model, version 3 (CAM3), for the second half of the 20th century. In particular, the relative importance of ozone depletion is contrasted with that of increased greenhouse gases and accompanying sea surface temperature changes. By specifying ozone and greenhouse gas forcings independently, and performing long, time-slice integrations, it is shown that the impacts of ozone depletion are roughly two to three times larger than those associated with increased greenhouse gases, for the Southern Hemisphere tropospheric summer circulation.
The formation of the ozone hole is shown to a affect not only the polar tropopause and the latitudinal position of the midlatitude jet: it extends to the entire hemisphere, resulting in a broadening of the Hadley cell and a poleward extension of the subtropical dry zones.
The CAM3 results are compared to and found to be in excellent agreement with those of the multi-model means of the recent Coupled Model Intercomparison Project (CMIP3) and Chemistry-Climate Model Validation (CCMVal2) simulations. This study, therefore, yields a direct attribution of most Southern Hemisphere tropospheric circulation changes, in the second half of the 20th century, to stratospheric ozone depletion.
This is a problematic issue for
i}Attribution,
ii}The underlying theory and,
iii)Future trends.
Here be no convergence, but a divergence with the expectations, ie a Clash of doctrines.
If the emission of carbonaceous aerosol was to be implicated in cooling during the 50’s – 70’s where is the expected ice melt in the antarctic from the increase in solar absorption in the ice, and the lower albedo that it induces. Just seems to be another example of the theory not fitting the observation.
All the warming and cooling from before the Maunder minimum in the C17th is probably better explained by this:
http://tallbloke.wordpress.com/2011/02/21/tallbloke-and-tim-channon-a-cycles-analysis-approach-to-predicting-solar-activity/
It’s amazing how much speculation 0.6 degrees per century can engender.
On that note, can someone tell me why we’d expect it to be zero? In more enlightened times we’d have scientists marvelling at just how stable our climate is. If nobody was being paid to worry about it then nobody would.
James, you are a breath of fresh air.
Have you ever wondered what temperature we would choose if we could adjust the thermostat. I am sure it would be rather warmer than the 15°C global average. We all depend on plants and they like 25°C.
If you are thinking of taking up some real estate south of latitude 60°south the annual maximum is minus 5°C.
Looking at the Earth in the most charitable way possible one might conclude that about half of the surface area is suitable for human habitation some of the time.
erl,
Personally, I prefer 20°C, no need for HVAC. But I am ready to sacrifice my 20°C preference for 25°C if plants and animals like 25°C better.
Jim D,
“You don’t even accept the 324 W/m2 back radiation,”
So you never quetion the validity of this 324W/m2?Amazing. Don’t call yourself a scientist or know better, thanks.
“I don’t think it is worth pursuing this conversation” I agree as you never responds to my calculations, atmospheric physical data and did not even bother your contraditions at d) in previous posts.
“I have given you facts and numbers”. You never question validity of those data and numbers, thats not a proper learning attitude. Facts can never come out of modeling data and numbers should be consistent with physical properties of materials.
SamNC, you can measure numbers like 324 W/m2 with basic scientific equipment, and the measurement agrees with theory. This part of atmospheric science pre-dates AGW by decades. It is called downwelling longwave flux at the surface. Do you have in mind that scientists have been writing papers about a fictitious quantity for decades, both in theory and observations?
Looks like you got duped by someone. I would not stand for that if I were you.
I just need you to show me how you get that 324W/m2 if you are a believer of that number is true not fictitious. Guessing is non-scientific. If you cannot show me that how you can get that 324W/m2 back radiation in calculations, say so, I am not the one will tease anybody who say, ‘I don’t know’. I would like to re-iterate that if you can help me how you arrive at 324W/m2, please do so. If you can’t, stop here. Thank you.
The KT update is here – http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/10.1175_2008BAMS2634.1.pdf
Their revised figure is 333 W/m-2 for back radiation – but there are a couple of approximations involved. There are for example large inaccuracies in absolute radiative flux data. But it is worth working through in detail – remember that there is a radiative imbalance (warming or cooling) which is dynamic and not static as in the final diagram.
I did note this statement in looking back over this paper.
There are spurious trends in the ISCCP data (e.g., Dai et al. 2006) and evidence of discontinuities at times of satellite transitions. For instance Zhang et al. (2007) report earlier excellent agreement
of ISCCP-FD with the Earth Radiation Budget Satellite (ERBS) series of measurements in the tropics, including the decadal variability. But the ERBS data have been reprocessed (Wong et al. 2006) and no significant trend now exists in the OLR, suggesting that the previous agreement was fortuitous (Trenberth et al. 2007b).
Dai et al talk about North American cloud and this probably increased along with rainfall in a warm Pacific multi-decadal mode – since shifted back to a cool mode. ‘Despite large inadequacies in monitoring long-term changes in global cloudiness with surface and satellite observations, data from a small network of military stations suggest an increasing trend in U.S. total cloud cover from 1976 to 2004’ You would certainly need to consider the COADS data reported by Clement et al 2009 and Burgman et al 2008 – which tells a different story in the Pacific.
Zhang et al 2007 talk about surface radiation, Wong is concerned with TOA radiative flux and makes no such finding. ‘The effect of the altitude correction is to reduce the magnitude of the tropical LW flux change from the 1980s to 1990s from the original 3.1 to 1.6 W m2. The correction increases the magnitude of the SW flux decadal change from –2.4 to –3.0 W m2.’ Warming (less reflected SW and a lower increase in emitted LW) in the tropics due to cloud changes. Remembering also that monitoring change is a lot more accurate than the determination of absolute values.
Any warming due to greenhouse gases is not obvious.
Robert,
Thank you for the link and I will study that update paper to see if I can get the answer from there.
That update was based on 324W/m2 which did not accounted for how it arrived at 324W/m2, in a circle.
324 is a global average. An example calculation can be done at the MODTRAN site for one location. Go to this page
http://geoflop.uchicago.edu/forecast/docs/Projects/modtran.orig.html
Select sensor altitude 0
Select Looking up
Try a few profiles such as tropical, US standard
Hit ‘submit the calculation’
Check Iout on the right side above the graph.
It will be a few hundred W/m2
At more advanced levels you can change surface temperature CO2, or H2O and cloud.
This is how you do the calculations. Very easy, because the code is written for you.
In case you miss it below.
324 is the KT97 value for back radiation – instead of playing on computers use your brain to assess the data, the methods, the limitations and the approximations.
You can’t hope to understand by plugging a couple of variables into a computer game.
So what would be your answer to how 324 is calculated? The good thing about MODTRAN is that there is a lot of documentation you can read on the Web at one extreme, and it least it gives you pictures at the other extreme.
Jim D,
How do you explain that Modtran3 V1.3 300ppm CO2 F=260.12W/m2 and K&T’s back radiation of 324W/m2 and later back radiation 333W/m2. Are these data non scientifically obtained?
These are individual clear-sky profiles. If you were able to average all these around the globe and add clouds, as K&T do, they get 324 W/m2. Understand?
Please calculate these individual clear sky profiles if you know and understand.
Clearly you didn’t understand.
Imagine the earth which has a lot of clear and cloudy profiles at any given time. Perhaps it can be represented by a few thousand. Then you average these over a year. Then you run MODTRAN for each of these hundreds of thousands, then you average Iout for each one, and get 324 W/m2. You can try it if you have time and want to write a paper on it.
Jim D,
Yes, I don’t understand. I had repeatedly ask you to calculate how to arrive at 324W/m2. You are unable to provide a calculation, don’t pretend you know anything or pretend you know better, your knowledge just no better than me. I am tire of your reply without a sincere reply and you are hopeless if I rely on you to get a true answer. You can stop responding to me now unless you can get that calculation.
Pekka,
“The large share of the CO2 band can be seen in the Figure 3 (red curve of the left picture) of this article
http://eospso.gsfc.nasa.gov/ftp_docs/validation/airsStatusReport_WaldenEtAl.pdf”
Your knowledge and a lot of reading is amazing. Thanks for the link. I will study it and raise questions as appropriate. I don’t just believe whatever is written by so call authority, unless I am fully convinced.
Pekka,
The figure 3 shows that radiation is something like 70mW/m2 against K&T’s back radiation of 324W/m2 which was blowup by 4628 times by measurement. Modtran3 v1.3 upward irradiance is 160 W/m2. These radiation data are contradicting and very confusing. Will you explain?
That data is from the Antarctic. The radiation fluxes there are much lower than for world on average, because the surface temperature is only 247K od -26C. The difference is even larger in back-radiation, because there is so little water in the Antarctic atmosphere. Thus the share of radiation that escapes directly to the space is larger than elsewhere and some of the backscattering comes also from higher up.
Compared to 288K the total IR radiation from surface is 46% less at 247K. The back radiation in the 15 um band is reduced by the same ratio, other back radiation is reduced even more.
The figure is also missing part of the spectrum. I didn’t check why they miss the longer wavelengths or lower wavenumbers below 500 cm^-1 (over 20 um in terms of wavelength).
Pekka,
Sorry my typo of Modtran3’s 160W/m2 which in fact should be 260.12W/m2 (at 300ppm CO2) which does not tally with the KT97 is 324W/m2 back radiation and not tally with 235W/m2 (97), 239W/m2(2007) up radiations. What a mess of these data!
Did you agree with KT97 back radiation of 324W/m2, 235W/m2 upradiation which is in contradiction of your CO2 1/3 down radiation per Modtran3 picture and per Figure 3 of the satellite measurement calibration?
Do you know how K&T get their 324W/m2? Will you show me your calculations?
324 is the KT97 value for back radiation – instead of playing on computers use your brain to assess the data, the methods, the limitations and the approximations.
You can’t hope to understand by plugging a couple of variables into a computer game.
Sorry , but really aerosol pollution causing cooling?
Of course a better explanation would be natural climate variability.
There is a poor relationship between atmospheric CO2 and manipulated global
temp record. Of course if your religion is based on the idea that man cause harm to environment, then of course you will make up plausible stories.
This is not science! As surgeon I follow Keynesian advice. When the facts change, I change my mind. What do you do sir?
I too have looked at that mid-century “bump.” It sits smack on top of World War II and tells us that there was a heat wave during that war. That is utter nonsense. The thirties were warm, not just in the US but also in Europe, and if that bump had been ten years earlier I would have believed it. I remember in the thirties my parents were complaining about the black winter we had, no snow, something they had not seen for a long time. That was about the time the US had the dust bowl but we were half a world away, on the eastern shore of the Baltic sea. But then the war started and the 1939/1940 winter turned out to be a dilly. Temperatures dropped precipitously and the Finnish Winter War was fought at a temperatures of minus forty Celsius. Next Hitler invaded the East and bitter Russian winters were as much an obstacle to him as the Red Army was. This did not let up and GI-s had to fight their way from the Battle of the Bulge to the German frontier in the coldest winter that west Europeans could remember. And right after the war, in 1947, a blizzard shut down everything that moved in New York City. My theory is that due to the war records were missing or screwed up and what was available bore no semblance to what really happened. There was a scramble to find records and eventually they ended up just copying from each other whatever they could and giving us that famous “Heat Wave of World War II.”
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