by Douglas Sheil
Despite major investments in incorporating land cover in climate simulation models, much remains uncertain, especially concerning the influence of land-cover change on cloud cover and rain.
It’s been over 16 months since our last guest blog on condensation-driven winds. That blog generated plenty of feedback so I hope that you may be interested in an update. We have published a number of papers further refining our ideas (see, e.g., here and here) and have working on several more (see, e.g., preprints here and here).
But here my aim is not to reopen debate on the technical details of the condensation theories, but rather to highlight advances and implications of more general interest. I focus on two papers (and highlight a few more at the end): one summarizes some recent advances in studying the links between rain and vegetation (here, free online until the end of June I believe) and another that examines how condensation and atmospheric pressure changes are related to forest cover (here, behind a paywall but also available at ArXiv). As the first paper is written for a general audience most space is devoted to summarizing the key message from the second paper.
Paper 1: “How plants water our planet”
The first paper is short and targeted at a biological readership. It argues that biology plays a much greater role in determining rainfall, and climate generally, than is widely recognized. It attempts to summarize recent advances that illustrate this argument and its importance.
The article notes that “despite major investments in incorporating land cover in climate simulation models, much remains uncertain, especially concerning the influence of land-cover change on cloud cover and rain”. This is not controversial. As one recent commentary on climate models notes explicitly rainfall over land remains hard to simulate because it is largely determined by ‘unresolved processes’. This represents the ‘main limitation in current representations of the climate system’ and ‘a major roadblock to progress in climate science’ (Science 340, 1053-1054).
I focus on rain, but the implications of the terrestrial water cycle are bigger. If you are interested in temperature it is worth noting that the vaporization of water consumes nearly half the solar energy reaching the Earth’s land surface and contributes to local cooling (and the redistribution of heat). Atmospheric moisture also impacts the climate in many ways: water vapour is a powerful ‘greenhouse gas’ and cloud cover influences planetary albedo (a measure of the solar radiation reflected into space).
One recent study (Nature 496, 347-350) estimates that transpiration (water vapour derived from plants) produces 80–90% of the atmospheric moisture derived from continents. This figure substantially surpasses previous estimates (20–65%). If the share of atmospheric moisture derived from vegetation is so much larger than previously recognised, then changes in vegetation may also have greater impacts. Until the processes underlying vegetation control of the water cycle are resolved, the potential impact of land-cover change on the regional and global temperature regimes cannot be estimated with confidence.
The review highlights some further advances describing how trees and forests may influence the global water cycle and associated ‘unresolved processes’. The biotic pump idea (see below) is only one of these exciting advances, though admittedly it appears among the most profound and controversial. Among other things I speculate that both forest loss and increasing atmospheric carbon dioxide may help explain a reduction in tropical winds, and changes in regional weather patterns.
I also suggest that changes in Walker Circulation may be influenced by the rapid forest loss occurring in South East Asia.
It is not controversial to suggest that we need a much better understanding of how land-cover influences climate. There are major gaps in our understanding. As Anastassia and Victor recently commented to me (when I shared a draft of this blog), much of what is currently considered “natural climatic variability” might in fact reflect the effects of human land-cover change if only we adequately understood these influences better. (Historically many regions have been subjected to major forest loss, and/or regrowth). This is one reason why it is crucial to take forests, and land cover more generally, into account in climatic reconstructions.
Please read the paper and judge for yourselves. It provides context for our second paper.
Paper 2: “Why we must reassess the role of forests for climate and for water security”
A commentary on Makarieva A.M et al. 2014 Journal of Hydrometeorology, 15, 411-426.
This is derived from a text that Anastassia and the team developed together (see here). I share it here, in slightly edited form, with their permission.
The effects of forests on weather are often viewed solely in terms of moisture recycling. That is, evaporation from forest returns moisture to the atmosphere where it can increase local rain. In our new paper, using a recent study as an example (Nature 489, 282–285), we discuss limitations in this perspective. Among other things, we argue that the existing global circulation models cannot be used for evaluation of the climatic effects of deforestation because of their inability to reproduce various phenomena that we have ascribed to a new mechanism we have termed the “biotic pump” – by this mechanism forests generate large-scale pressure gradients that cause winds to flow and bring moisture from oceans to land.
Below we explain some highlights from the second part of our study that examines the pressure relationships that our theories predict. Here we have tried to summarise and illustrate the key ideas for a general readership.
Moist air arrives to land in the lower atmosphere, rises and becomes depleted of moisture (as clouds form and rain falls). This dry air returns to the ocean in the upper atmosphere while the net imported moisture returns to the ocean via rivers (and other minor flows). Air circulation models describe the aerial component of the water cycle: i.e. how much moisture is carried by winds. Measures of river runoff provide an independent check on any such models’ validity as this runoff must match what the winds bring in. (Unfortunately the circulation models escape any such check in the oceans as there is no runoff to measure).
Current air circulation models do not pass this check: inputs don’t match outputs. For example, the Amazon models can only account for half the measured river runoff. Similar considerable discrepancies are common for all regional models and no fix to this problem has yet been identified (e.g., J. Hydrometeor 12, 556–578).
In our recent paper we provide new evidence for the biotic pump. We analyse the relationship between wind direction and surface air pressure in forested and deforested regions of the Amazon basin. This highlights how the intense evaporation from forest creates low pressure. Let’s take a look – schematically – how this condensation-evaporation cycle works.
Immediately after rain the local atmosphere is relatively dry (water vapour has condensed and precipitated). Winds are negligible. The atmosphere slowly regains water vapour via evaporation.
Owing to the high cumulative surface of leaves, the forest enriches the atmosphere with water vapour more rapidly than does the ocean. Total air pressure in the area slowly grows reflecting the accumulating water vapour. (Our analyses show that rainy days in the Amazon forests are on average characterized by a slightly higher pressure than the rainless days. In the deforested region the opposite is true – we discuss this is greater detail in the paper (see Section 4b,c), but the pattern is consistent with the biotic pump.)
Rainfall probability as a function of the total amount of water vapour in the atmosphere (CWV). As used in Fig. 5 of Makarieva et al. (2014) based on the data of Holloway and Neelin (2010).
Small differences in evaporation rates translate into large differences in the probability of rainfall due to the sharply rising relationship between water vapour content and the likelihood of rain. Thus rain is much more likely to start again over the forest.
Once sufficient water vapour has accumulated over the forest, condensation begins. Local air pressure starts to decline. In contrast to the gradual process of water vapour evaporation, condensation can occur quickly.
The resulting pressure differences now draw wet air from the ocean to the forest, this air rises and cools. Now moisture generated locally via forest evaporation precipitates on land together with additional moisture brought from the ocean. This additional moisture is what ensures land remains wet while rivers keep running back to the ocean.
Thus, rather than merely recycling moisture, forests actually drive the water cycle on land. Recognition of this role will lead to re-evaluation of the importance of natural forests and the need for forest conservation to prevent water scarcity. We urge a major reassessment of the role of forests in atmospheric dynamics.
Other developments
One interesting study is provided by German Poveda, Liliana Jaramillo, and Luisa Vallejo, who have used the biotic pump ideas to interpret the behaviour of the so-called “Caribbean Low Level Jet” which curves towards South America against the prevailing trade winds. The observations are consistent with forest generating low pressure to draw in winds. (Anastassia and Victor offer further comment here ).
Another interesting paper is by Mark Andrich and Jörg Imberger who seek to distinguish rainfall changes in Western Australia caused by land-cover and more general shifts in the Hadley circulation. Their conclusion is that land-cover (i.e. tree loss) is the dominant factor to explain precipitation changes. (See also here).
For more information see
Sheil D. (2014) How plants water our planet: advances and imperatives. Trends in Plant Science 19, 209-211 doi: 10.1016/j.tplants.2014.01.002
Makarieva A.M., Gorshkov V.G., Sheil D., Nobre A.D., Bunyard P., Li B.-L. (2014) Why does air passage over forest yield more rain? Examining the coupling between rainfall, pressure, and atmospheric moisture content. Journal of Hydrometeorology, 15, 411-426, doi:10.1175/JHM-D-12-0190.1. Abstract.Supplemental information.
JC note: This is a guest post submitted to me by Douglas Sheil. As with all guest posts, keep your comments relevant and civil; moderation will be heavier than usual.
Related: by the early 20th century, the eastern half of the United States was largely denuded of trees to make way for agriculture. That trend has been reversed and the forests are returning. Bill McKibben, yes, THAT Bill McKibben wrote about it in 1995 in the Atlantic Monthly:
http://www.theatlantic.com/magazine/archive/1995/04/an-explosion-of-green/305864/
@pittereaton Thanks for the link. I am interested in studies about how historical farming may have affected North-east weather patterns. Would this not affect temperature measurements over that time? Instead of global average temperature, I like to see regional studies of temperature changes where the reason for the change can be investigated. This has been done in the Netherlands and is one of the reasons I accept as fact that the climate is changing in many places. But global averages, that contain almost no temperatures from Africa and South America, are less convincing.
Rose
Bill McKibben is not a reliable source of anything but hyperbole. The eastern US was not then (early twentieth century) and not since “largely denuded of trees by agriculture”.
http://0.tqn.com/d/forestry/1/0/D/t/forest_facts_area.JPG
US Forest from 1750 – 1900 reduced from 1 billion acres to 750 million acres. It has been stable since then.
http://0.tqn.com/d/forestry/1/0/E/t/forest_facts_region.JPG
The northeast in particular went from 300 million acres to 150 million acres. This is not “largely denuded”. If there were any more than 50% left untouched it would be more accurate to say it was left largely intact.
Bart R writes of Roy Spencer in comments below:
Bart R | April 16, 2014 at 12:36 pm |
Dude, if the only source you can come up with that tells you this thing is a known-to-be biased bible-thumping psuedoscientist with tight reins over the known-to-be malfunctioning satellite and all its transmissions, that source cannot be called “common knowledge”.
Is there any moderation in this joint or is that the tone Curry finds acceptable?
@David Springer There are no data sources on the plots you referenced. I am not sure if there is a technical definition for “denuded”. I usually check the sources of articles that I read, including Bill McKibben’s. I have heard over the years that there is little old growth forest in the north-east. If it is all second growth, that means it must have been removed at some point, although maybe not all at once. Since we do not have satellite images from that time, it is difficult to say with certainty.
Source of graphs US Forest Service:
http://www.fia.fs.fed.us/slides/major-trends.pdf
Denude isn’t a technical term. We then use the dictionary definition.
http://www.merriam-webster.com/dictionary/denude
Forest Service Source of graphs (working link). Not sure why the above didn’t work.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad=rja&uact=8&ved=0CCgQFjAA&url=http%3A%2F%2Fwww.fia.fs.fed.us%2Fslides%2Fmajor-trends.pdf&ei=iLlOU9jrPI-OyATKvYLYAQ&usg=AFQjCNE05dKsQC_EadB53IN2JF8wdgGxwA&bvm=bv.64764171,d.aWw
There is another change in U.S. forests, but I am unable to judge its importance. I recall reading years ago that early colonists to America found the forests to be “park-like” – that is largely devoid of under-growth. This was possibly a combination of native burning practices and higher game populations, which prefer to winter-feed on younger tree shoots and first year seedlings.
I grew up on a native Indian reservation smack dab in the middle of the Allegheny mountains in western New York state The rez borders on a massive pristine state park by the same name that spans two states. It’s all park-like with little understory where the topography permits an unbroken canopy. Where the Allegheny River river cuts through and around larger streams its impenetrable jungle to the extent of their floodplains. Where I live now on the edge of the Edward’s plateau in Texas’ Hill Country fire suppression has allowed shallow rooted Mountain Juniper to become so dense from ground to 30 feet high it’s hard to walk through it without getting all lacerated by dead tinder-dry branches. The Juniper don’t survive fires. The oaks can get burned to trunks of charcoal and they immediately send out fresh green shoots from the charred but deep rooted remains.
Fire suppression does more than anything else to change the nature of forests in my opinion regardless of whether they’ve been logged or not. Generally you log about every 25 years and don’t clear cut just make some logging roads and take out the choice hardwoods with long straight bolts like cherry, oak, maple, walnut, chestnut (none of those around anymore the chestnut blight wiped them out in the early 1900’s) and others. Chestnut was really popular and lots of homes over a hundred years old are still standing strong with chestnut frames. Cherry makes for extremely durable attractive floors superior to oak. The poh folk use a lot of pine but even that lasts about forever if well maintained. A popular compromise is oak or cherry the first 12 inches in from the walls then use pine the rest of the way and cover it with a rug so the whole floor appears to be hardwood.
Old growth, not dead but static, and not very diverse.
========
@David Springer Thanks for the sources link (the first one had some characters at the end that caused the error). I agree that “denuded” is extreme. (Bill McKibben is a journalist, not a scientist.)
However, the forest was being partially cleared and the land farmed. This has probably had an effect on the temperatures measured. I would like to see the temperature variations explained rather than just defined as “natural variability”.
Not all of the land was denuded for agriculture. Much of it was mountainous and not arable, but was denuded for the wood it supplied, at a time when almost all houses were still heated by wood. When the wood ran out, people switched to coal for home heating, and when the switch to coal was complete, the trees grew back in the non-arable regions. The land that was denuded for agriculture is generally still used for agriculture.
After your last post on condensate driven winds I tried using available land use change data, which is not all that impressive, to look for a “land use signature”. That is complicated by the different cultural influences on land use change. Asian, primarily Chinese, land use is more water conservation intensive, rice patties etc. while Russia/ Former Soviet Union was more water abuse intensive, Aral desertification for example. Most of the world falls somewhere in between. With such a huge range of hydrological impacts I imagine teasing out the biological influence is a bit of a challenge.
captdallas2 0.8 +/- 0.2 |
thanks – I am also interested to find good long term data to better explore these relationships (or encourage others to do so). I have a few leads but little real progress so far (a few publications like the Andrich and Imberger noted in the blog above). Indeed good data is only the first challenge; the second challenge is to robustly decipher the changes when there are often multiple plausible explanations.
Of interest may be the feedbacks in botany and soil and water microbiology to changing CO2 levels, increasing temperatures and shifting patterns of extreme weather (drought, flood, resultant fire patterns) alongside the first order extra-climatic forcings, like human-started fires, human fire suppression, urbanization, watershed mismanagement and the like.
You know, Roy Spencer actually argues, despite the evidence of shifting botanical zones and the northward and higher altitude march of plants and animals matching AGW that the continental USA hasn’t warmed since 1973.. which tells us either every plant and animal in America is wrong, or Dr. Spencer is wrongheaded.
By your reckoning, the tropical rainforests should be just about devoid of plant and animal life by now.
“every plant and animal in America”
Barty,
Do we have to go through the hyperbole stuff with you too?
Andrew
BartR
Is this the article where Roy Spencer makes the claim?
http://www.drroyspencer.com/2010/02/spurious-warming-in-the-jones-u-s-temperatures-since-1973/
His methodology seems to be to use records that cover the entire period. You have obviously studied this more than I have so where does his methodology go wrong?
tonyb
phatboy | April 15, 2014 at 1:09 pm |
Between the two of us, I believe it likely I have spent far more time in far more rainforests than have you, even knowing nothing about you other than what you have posted here.
Are you familiar with the subject of deforestation, forest vegetation growth (more above-soil mass in undisturbed regions, but less plant health) patterns, the hormonal mechanisms of plant response to CO2 changes, and shifting microbial capacity for nitrogen-fixing under conditions of CO2, heat, drought and flood stress?
You likely think you are; you may think you’ve seen studies that tell you tropical rainforests are gaining mass, ergo fantastic contradiction to the claims of negative impacts of climate change. Well, you’d still be wrong.
climatereason | April 15, 2014 at 2:48 pm |
I’ve obviously studied this at all?
Pfft. I don’t see that this is obvious.
Someone like http://bbickmore.wordpress.com/2011/02/25/roy-spencers-great-blunder-part-1/ has studied this. I may have simply familiarized myself with such a critique in passing. Or not, since all I really need to know to make my claim is the Spencer claim’s existence and the trends in habitat change in wildlife in America.
So I don’t need to know what’s specifically wrong with Dr. Spencer’s inept methodology to say its results are in disagreement with copious evidence. I imagine mostly what’s wrong is confirmation bias, fallacy and propaganda.
You tell me; you’re familiar with my methods; I’ve recently refreshed the list of techniques of propaganda in anti-Science and demonstrated how to apply them in the Curry v. Trenberth topic; fallacy is easy to spot; and, we all know Dr. Spencer’s bias: is my guess correct?
Bart R, unless you can quantify your assumptions with verifiable figures then I can only assume you’re talking out of your hat.
Life, in general, favours warm to hot climates over cool to cold ones,
and any spread of species to higher latitudes and altitudes is likely to be just that – a spread into less-crowded areas.
And, FYI, I spent many years living in Africa – you?
It’s probably the following link which I posted recently that got Bart’s JC SNIP.
http://www.drroyspencer.com/2012/04/regional-u-s-population-adjustments-to-surface-temperatures-since-1973-still-little-warming/
Others from same source:
http://www.drroyspencer.com/2012/04/new-u-s-population-adjusted-temperature-dataset-pdat-1973-2012/
http://www.drroyspencer.com/2014/01/u-s-temperatures-1973-2013-a-alternative-view/
http://www.drroyspencer.com/2012/04/ushcn-surface-temperatures-1973-2012-dramatic-warming-adjustments-noisy-trends/
It’s common knowledge that CONUS has not participated in so called “global warming”. JC SNIP
Bart R
From the Spencer article cited by tony b it looks like neither the ISH data nor the Jones CRUTem3 record show any significant warming in the USA since 1973.
So all that hypothetical mass northward migration of “every plant and animal in America” you cited must be happening for some other reason beside warming (observed human mass migration in a southerly direction or simply statistical nonsense?)
Fuggidaboudit, Bart. It’s hokum.
Max
Bart R
Use your head.
Data from US Census Bureau show that there has been a steady shift of human population from the northern to the southern states in the USA. States like NY, NY and OH are losing population while TX, FL and AZ are growing.
http://www.bloomberg.com/news/2010-12-22/u-s-population-shift-accelerates-to-south-west-states-2010-census-shows.html
Humans displace other species – duh!
Have you ever wondered why the wolf disappeared from central and southern Europe and moved north to Siberia and Scandinavia? (It sure as hell wasn’t because of “global warming”.)
Get serious, Bart – otherwise you just look silly.
Max
manacker you really think species and plants are moving north because humans are moving south?
seriously? and that’s certain is it. Funny how you jump at that particular conclusion.
Myself I am going with the overwhelming evidence for warming as the explanation rather than such nonsense.
Species adapt to colder / warmer / wetter / drier climates by way of natural selection.
…as well as lower / higher CO2 concentrations
phatboy | April 15, 2014 at 3:48 pm |
Africa’s a big continent, and relatively little of it qualifies as rainforest compared to the Pacific Rim or South America. Don’t take from this that I mistrust vague generalities from strangers on the internet. Per se.
You must be overjoyed by the wealth and abundance of flora and fauna in the generally hot Sahal compared to the wastelands of frigid upstate New York or Michigan. I find your hot-cold generalization specious and self-serving, not relevant, and in particular simply false, so I must conclude your African experience has not been particularly edifying, which would require that I unmake the one assumption I had: that I was discussing with a person of average cognitive process but no experience a thing that anyone of modest reasoning power might grasp with even a little exposure to fact.
Citing natural selection for migration certainly disabuses me of the urge to make that same assumption of you again.
The simplest explanation demanding of least exceptions that most universally applies to the shifting of botanical zones in the continental USA since 1973 is AGW. There are dozens of similar shifts in US weather patterns on the climate timescale, in hydrology and avalanche shifts resultant from snowpack changes, in wildfire patterns, and more. Dr. Spencer is simply bad at math, or biased, or intentionally misled. Pick at least one.
Bart R., the last ice-age wiped out the Earthworm in North America. The European earthworm was introduced by the English, in potted plant. The earthworm completely changes the soil and completely changes the way that forests grow.
Earthworms colonize slowly 6m/y. However, they are where ever people colonize a habitat, they introduce earthworms.
So if someone builds a house and garden on a mountain, the mountain has newly introduced soil biotica.
Bart R, for someone with such disdain for generalisations, you sure make an awful lot of assumptions from so little information.
But let’s not sink any further towards ad-hom territory.
I never implied that natural selection was the mechanism for migration, merely that it’s one of the ways by which they can migrate into less favourable areas.
Species do spread – that’s their nature – and when they start spreading into less favourable areas they start dying off, except for the hardier individuals which then remain to colonise the new area.
It’s a slow process, but it does happen.
And yes, life in general does tend to favour warmer over colder, as well as wetter over dryer. As a tiny example – not meant as a generalisation – how often do you mow your lawn in winter?
Webphut, I will not sink to your level, so I won’t say anything.
FYI, ‘phat’ has nothing to do with ‘fat’ – any connection is purely ironic.
Drop the schoolboy insults and we’ll get along just fine.
I don’t believe I’ve seen anything from you on this thread which resembles any sort of science whatsoever.
In fact, every single one of them is nothing more than gratuitous insult.
phatboy | April 16, 2014 at 2:35 am |
Lawn is a poor use of land; the typical grasses are superficial and require intensive watering, chemical use and work to obtain what invariably is an ugly and pedestrian outcome.
I’ve replaced my lawn with deep-rooting, low-maintenance pollinator-friendly plants that encourage microbial and botanical sequestration of biocarbon more deeply beneath the surface while decreasing NOx emissions, without insecticides. You should try it. Never mow again, spend less for better curb appeal and a more cozy barbecue backyard, and provide habitat for beneficial native species.
Mow lawn. What a primitive assumption.
Just let it go wild. Don’t water, don’t fertilize, don’t put down impervious cover except where absolutely necessary. That’s what I do. Not counting my driveway I have 3% impervious cover. The driveway takes the total up to 10%. Due to 25% slope the concrete driveway is a necessity. South central Texas. Despite the drought everything is covered by green growing things. Where I removed trees to make a yard I simply weedwhack whenever stuff gets higher than about a foot which happens twice a year on average. Native plants that are happy staying close to the ground have taken over those areas. Anything thorny or spiky gets pulled out of the ground every couple of years to minimize it.
Unfortunately for many people that isn’t an option due to city statutes and HOA rules about keeping a mowed lawn that looks more or less like all the other homes.
DocMartyn | April 15, 2014 at 10:09 pm |
Spilled milk. Boo hoo. Try to stick to relevant facts.
Earthworms are shifting with climate change, like any other CO2-sensitive, temperature-sensitive, flood and drought sensitive species. That they’ve been reintroduced in the past 500 years after a 100,000 year absence is hardly on topic. That cross-species shifts corresponding with a warming and more extreme climate are documented across America is the point, and that shift is impossible to explain by potted plants brought across on the Mayflower.
manacker | April 15, 2014 at 4:19 pm |
Wolf? Interesting you mention wolf.
Because coyote, the wolf’s warm-lovin’ cousin, has had a resurgence north and south, albeit again the coyote population shows distinct adaptations to the shifting climate, too, that show America is warming.
Coyote distribution puts the boots to your humans-like-to-live-in-warm-places-and-so-force-species-north proposition.
And the premise that soil microbes are shifting north because they don’t like human neighbors is, frankly, too absurd to contemplate.
“I’ve replaced my lawn with deep-rooting, low-maintenance pollinator-friendly plants that encourage microbial and botanical sequestration of biocarbon more deeply beneath the surface while decreasing NOx emissions, without insecticides.”
lol. Do you have other superpowers? Lilies smell better?
Andrew
David Springer | April 16, 2014 at 9:33 am |
Others from same source:
..
It’s common knowledge that CONUS has not participated..
Dude, if the only source you can come up with that tells you this thing is a known-to-be biased bible-thumping psuedoscientist with tight reins over the known-to-be malfunctioning satellite and all its transmissions, that source cannot be called “common knowledge”.
Land-based stations disagree with UAH. Animals disagree with UAH. Plants disagree with UAH. UAH has no transparency, and is openly hostile to inspection of its methods. They do not share their publicly funded raw data, and don’t even bother to make the excuse that the people asking about it may find something wrong with it.
Bad Andrew | April 16, 2014 at 10:04 am |
I’m a regular Johnny Appleseed in a cape and cowl.
Hey Bart if you’d opened the link to Spencer you would have found he used the CRUTem3 dataset not UAH satellite data.
I’ll understand if you need to take a moment to get your foot out of your mouth before saying you’re sorry.
A man with as much bias as Bart R has as much chance of entering the Kingdom of Climate as a camel does of passing through the eye of a needle.
============
“I’ve replaced my lawn with deep-rooting, low-maintenance pollinator-friendly plants that encourage microbial and botanical sequestration of biocarbon more deeply beneath the surface while decreasing NOx emissions, without insecticides.”
Nice, in a nauseating kind of way.
David Springer | April 16, 2014 at 1:35 pm |
Why would I give four-year-old links to debunked claims any more slim web traffic than they already get?
I mean, if you’d opened the link to http://bbickmore.wordpress.com/2011/02/25/roy-spencers-great-blunder-part-1/ you’d have known better than to make such absurd comments.
You didn’t even have to open the links to see they were from 2012 and 2014. Amazing.
Baart R: Between the two of us, I believe it likely I have spent far more time in far more rainforests than have you, even knowing nothing about you other than what you have posted here.
That is a worthless claim. If you have more knowledge to share, share the knowledge, citing sources. Just “Being There” isn’t acquisition of knowledge.
Bart R: I’ve replaced my lawn with deep-rooting, low-maintenance pollinator-friendly plants that encourage microbial and botanical sequestration of biocarbon more deeply beneath the surface while decreasing NOx emissions, without insecticides. You should try it.
I have done the same. So what?
Matthew R Marler | April 16, 2014 at 3:19 pm |
Nice to not have to mow, isn’t it?
Speaking of, thanks for confirming my reasoning about Mr. Africa. Just being there isn’t enough.
Though I’m pretty sure you’ve been an avid reader here long enough to have been exposed to the many times I’ve cited exactly the sources you call for. If not, go back and READ HARDER.
Here’s the basic analysis I have for the Spencerian 1973-2009 claim:
First, the original is almost four years old, so you have to ignore everything we’ve learned in the ensuing four years to accept the claim, which would include the deprecation of CRU3 in favor of CRU4, the discovery of manifest issues with UAH satellite, the debunkings of the Spencer figures by the wider scientific mainstream, the many studies showing other evidence for USA warming trends, and all that CONUS warming on record since 2009.
http://www.woodfortrees.org/plot/hadcrut3gl/mean:5/mean:7/plot/hadcrut4gl/mean:5/mean:7
Second, I’d have to slog through it, and knowing the first objection, that’d be pointless.
Third, it’s so cherry-picked as to be absurd: less than 2% of the Earth’s surface is reflected in CONUS. Why pick 1973 as a start year, other than confirmation bias? Why assume the improvised figures gleaned from weather station datasets adequately capture the changes in CONUS climate? So, on its face, anti-Scientific propaganda.
Well Bart you’ve at least moved past dismissing Spencer by calling him a bible thumping psuedoscientist [SIC]. Maybe learn how to spell pseudoscientist next time so you only appear to be a disgusting bigot instead of a digusting bigot who can’t spell.
Bart R,
Argumentative.
You know exactly what I meant.
Bart R convinces himself. Not Abbey Road, but Abbey Somewhere.
==========
Bart R – let me know when New York City is part of the rain forest. It has move so far, eh?
Okay, you made me look at http://www.drroyspencer.com/2014/01/u-s-temperatures-1973-2013-a-alternative-view/ ..
The ‘UHI adjustment’ fudge factor is high by an order of magnitude, doesn’t account for urban cooling shadow effects, and fails to take into account the 2008 meltdown that reduced urban activity.
The link to the Goddard thing was.. just a waste of time.
Truly, Dr. Spencer’s CONUS numbers redefine ‘useless’.
Huge huge progress now. You actually clicked on the link before criticizing what lay beyond it. If you continue at this rate you could be almost be mistaken for an intelligent thoughful adult before the pause has gone on for so long that the AGW narrative dies completely. Maybe six years. Keep on trying I’m not giving up on you yet!
David Springer | April 17, 2014 at 1:35 am |
I have no excuse for the horrible pun on suede-o-scientist.
Puns have no place on a serious science blog where spelling counts.
> Nice, in a nauseating kind of way.
Then try thyme, Poker.
National Academy of Sciences in US published a recent land use modeling assessment with good information of existing state of art measurements here.
http://www.nap.edu/catalog.php?record_id=18385
Titile is advancing land change modeling opportunities and research requirements,
Can read it for free online if you register with them.
Scott
Now that the UK (and perhaps other countries) is converting power stations from using fossil fuel to use wood pellets instead, what effect will that have on deforestation ?
From a recent post here at Climate Etc. it’s currently increasing deforestation in the southeast US. Maybe they will replant all the bottomland forest they’ve harvested to ship to the UK, or maybe the denuded land will be left to natural processes – I haven’t researched that far yet.
I have made up my mind that the Woodchips-to-Drax project is one big Onion satirical stunt, possibly the most elaborate hoax in the history of satire.
If this is not the case, I’ll be trying to change my species description to “aphid” or “possum”. I just wouldn’t want to belong to the same biological group which conceived Woodchips-to-Drax. It’s the embarrassment factor, you see.
If the “impact of land-cover change on the regional and global temperature regimes cannot be estimated with confidence” and we have seen a divergence from model temperature projects and measured temperatures, when are climate scientists going to admit that they are playing Swami the Great with their predictions?
Changes and non changes in land use along the Hudson River, US, impacts over time on temps and precipitation from Tony B. and link
to Climate Audit on Central Park temp adjustments.
http://noconsensus.wordpress.com/2009/11/25/triplets-on-the-hudson-river/
I’ve said for years that if you cut down the forest, you cut down the clouds. So in general I agree with the analysis.
However, I didn’t understand this statement:
Huh? Water vapor makes air lighter, not heavier. What am I missing here.
w
It makes air less dense, not less heavy. You can’t make the total air column (which determines the pressure) lighter through adding mass to it. Adding water vapor is adding mass.
Huh? Water vapor makes air lighter, not heavier. What am I missing here.
Apparently a lot. Water vapor may be lighter than air, but water vapor is a small percent of air. Water Drops are heavier that air and that is still a small percent of air, but is huge. How much water is in the air does not matter as much as how much water passes through. When oceans are warm and the surface is liquid a hugh amount of water goes into the atmosphere and falls as rain or snow. When oceans are cold and the surface is frozen ice, extremely small amounts of water sublimate and goes into the atmosphere and fall as rain or snow.
The Polar Ice Cycles do have a Set Point, the temperature that water freezes and thaws, and the snowfall is turned on and off when temperature crosses the set point.
This is what does the fine tuning of Earth Temperature.
It kinda makes sense, common sense, doesn’t it!
Ran across this yesterday.
Everything you always wanted to know about the density of moist air, but were afraid to ask.
It’s peer-reviewed so it’s got to be good :-)
thanks for this link!
Hi Willis
“Water vapor makes air lighter, not heavier”
The point here is not the weight but the pressure. If we add (any) molecules to a given volume of gas at a given pressure the local pressure will rise.
(To address the weight point further: yes, surface pressures, on average, balance the weight of the atmosphere above; but this balance occurs in the same way that we don’t get crushed by an airplane that flies directly overhead. i.e. the pressure of the local atmosphere is not necessarily the same as the weight held by the air above).
let me say that again
“If we add (any) molecules to a given volume of gas at a given temperature the local pressure will rise.”
Willis isn’t missing anything that was pointed out in response. Adding water vapor to dry air displaces heavier molecules of nitrogen and oxygen.
http://www.engineeringtoolbox.com/density-air-d_680.html
What Willis is missing is temperature. Water vapor takes sensible heat and locks it up as latent heat until condensation. This lowers the sensible temperature of the air mass and that in turn increases its density. If data show that pressure is lower then it’s because the increase in density caused by lower temperature outweighs the decrease in density caused by more water vapor content.
Local pressure does not depend on the weight or mass of the molecules involved.
e.g., for a fixed volume V
P = nRT/V
where P is the absolute pressure of the gas, n is the count of molecules (measured in moles), R is the ideal, or universal, gas constant, and T is the absolute temperature of the gas.
No mass or weight involved.
If you have your gas in a box in vacuum it does have weight (note that n = mass divided by molar mass).
See http://en.wikipedia.org/wiki/Ideal_gas_law
Note also that if one gas “displaces” another this implies a prior pressure gradient has been established.
David Springer, density and temperature are irrelevant. Ground level evaporation adds weigh to the air column and this weigh is the sole contributor to the pressure at ground level. (No *exactly* true, though, since variable rates of convection through the column will transfer momentum through it and cause transient pressure waves — but that’s not what’s at issue here). If some of the mass in the column is displaced as a result of the water vapor addition, it can only be displaced vertically or laterally. If it’s *all* displaced laterally, then there will be zero increase in pressure, but that’s a lower bound. So, there is no justification for Willis’s expectation that pressure will diminish as a result of a diminishing local density. The weigh of the column can only increase.
“Local pressure does not depend on the weight or mass of the molecules involved.
e.g., for a fixed volume V
P = nRT/V”
Sure but at equilibrium, the pressure at ground level, multiplied by some surface area, will be such as to balance the weigh of the total column over that area. I am sure you didn’t mean to contradict this. It’s consistent with what you said.
Also, one comment regarding the airplane passing overhead. It does actually transfer it’s full weight over “you” — though it’s spread over a wider area than just your skull, for sure. The aerodynamic lift provided by air to the plane, which is equal in magnitude to its weigh, is also applied, with reverse sign, to air through Newton’s third law. This creates downward momentum in the local air column that must eventually (and rather quickly) be transferred to the solid ground. Conservation of momentum (which is a consequence of the third law) ensures that this will result in a transient increase in ground level pressure which, when integrated over the surface and over time, will equal the aerodynamic lift on the plane (it’s weight) integrated over the same time period. So, in effect, this transient increase of pressure at ground level exerts a force on the ground equal to the weigh of the plane, though spread over a wide area.
I think Douglas is insisting of factors that effect transient changes to local pressure resulting from adding water vapor molecules, whereas I was insisting on equilibrium changes over some wide homogeneous area. In both cases, we expect pressure to increase, though. The argument that pressure will be reduced because a local parcel of air would expand and thereby have a reduced weigh is invalid.
Rereading what Douglas said about the airplane, I see that my comment merely expands on the same point he was making.
Evaporation at surface means that there’s a flux of molecules from liquid to air. Choosing a fixed volume that encloses the area of evaporation there cannot be any persistent increase in the number of molecules in that volume. Thus there must be a equal net flux through the surface of the chosen volume. That net flux means that the pressure inside the volume must be a little higher relative to the rest of the atmosphere. Thus strong evaporation leads to a small addition in the pressure in the region of evaporation. The increase is, however, very small, almost certainly too small to observe.
Pekka. Think harder. Maybe review some basic science first. This goes for the rest of y’all too except for Willis who doesn’t seem to be suffering from cranial rectosis in this particular instance.
Strong evaporation creates a convection cell. The air pressure in a convective cell is lower than that surrounding it. Measurably so.
http://en.wikibooks.org/wiki/High_School_Earth_Science/Air_Movement
Humans may be insensate, but the system ain’t.
==========
Dan Hughes: Everything you always wanted to know about the density of moist air, but were afraid to ask.
thank you.
note to others: not paywalled!
“Strong evaporation creates a convection cell. The air pressure in a convective cell is lower than that surrounding it.”
Evaporation doesn’t create a convection cell by itself. It results in an increase of latent heat in the air as relative humidity increases. But it actually *reduces* the tendency to convection because this latent heat increase takes place at the expense of a rise in temperature that would otherwise occur. I.O.W. the energy from the Sun and warm ground goes into evaporating water *rather* than into sensible heat flux from ground to air. It cools both the surface and the air immediately above it. It’s only when the dew point is reached that this latent heat is returned to the air parcel where condensation occurs. This is what will trigger convection — or increase it when it already was occurring because of a temperature gradient that was already larger than the lapse rate due to sensible heat flux.
Yeah actually strong evaporation does produce convection cells, Pierre. They’re commonly called afternoon thunderstorms.
I suggest at this point you learn about the first rule of holes. When you’ve you’ve dug yourself into one the first thing to do is stop digging. You’re wrong. Stop digging. This is science taught in America before the kiddies are ten years old.
Try this link there’s lots of pictures and not many big words:
http://schools.dcsd.k12.nv.us/ses/class/rmccrear/Thunderstorms.htm
Here’s page that teaches about hurricanes through playing a game courtesy of those fun folks at NASA who put Americans on the moon to play golf. And we left our golf carts there with the keys in them because no other bloody country can reach them.
Anyhow, as hurricane develops it goes through a stage called a tropical depression. It’s called a depression because the friggin’ atmospheric pressure is low over a very large region and it’s low because the heat from the tropical sun evaporated a buttload (technical term for “a lot”) of sea surface which got locked into a positive feedback cycle of faster and faster evaporation and condensation. If the wind sheer is just right she gets organized and pressure drops even lower to hurricane level. Generally the lower the pressure the stronger the storm.
Write that down.
http://scijinks.jpl.nasa.gov/hurricane
Now where exactly was it you erroneously thought evaporation raises atmospheric pressure? High pressure areas are charactized by dry air and clear skies. You have all the basics of weather systems bass ackwards.
Pekka wrote: “Evaporation at surface means that there’s a flux of molecules from liquid to air. Choosing a fixed volume that encloses the area of evaporation there cannot be any persistent increase in the number of molecules in that volume. Thus there must be a equal net flux through the surface of the chosen volume. That net flux means that the pressure inside the volume must be a little higher relative to the rest of the atmosphere.”
Yes, this flux must occur as you state in any volume element above the surface where evaporation occurs. But the wider this homogeneous area is (e.g. a very large forest, as opposed to a small bush) the most this flux will be limited to the top of the enclosed volume. This means that most of the flux out of the volume will create an equal flux in the next volume on to of it — and so on. I think you had neglected that. The net effect, of course, is to add (almost) all the evaporated water the local atmospheric column. Hence the increase in pressure, will be (almost) exactly the weight of the evaporated water divided by the surface area. This isn’t necessarily negligible. The authors of “Why does air passage over forest yield more rain?” indeed measured it.
…the next volume [element] on to[p] of it…
‘If you cut down the forests you cut down the clouds.’ Ironic ain’t
it that use of fossil fuels have spared much of the landscape from industrialization. Before fossil fuels energy was grow n on land and
it needed lots of land. to grow it. The world economy needs lots of
joules of energy if it is not to be run by slaves. According to Matt
Ridley’s ‘The Rational Optimist’ Ch 10:
‘For Britain to power itself w/out fossil fuels would take sixty nuclear stations, wind farms covering ten percent of the land,solar panels
the size of LIncolnshire, eighteen Greater Londons growing bio-
fuels, forty-seven New Forests growing fast rotation harvested
timber, hundreds of miles of wave machines off the coast, huge
tidal barrages in the Severn Estuary and Strangford Lough, and twenty-five times as many hydro dams on rivers as there are today.’
Imagine what it would do to the landscape and wildlife suffering the
loss of open country, estuaries and free flowing rivers?
“Anyhow, as hurricane develops it goes through a stage called a tropical depression. It’s called a depression because the friggin’ atmospheric pressure is low over a very large region and it’s low because the heat from the tropical sun evaporated a buttload (technical term for “a lot”) of sea surface which got locked into a positive feedback cycle of faster and faster evaporation and condensation.”
Sure, there is a depression. But condensation is an essential part of the formation of a tropical cyclone. It’s the release of latent heat though condensation that maintains the temperature of the rising mass of air above the temperature of the surrounding air in spite its adiabatic expansion as it rises. The rate of drop in temperature is thus lower than the surrounding lapse rate.
This is irrelevant to the case we were discussing when evaporation occurs below the dew point over a forest. At this stage, the evaporation doesn’t cause a depression since there isn’t any cyclonic activity.
And, in any case, your explanation has nothing whatsoever to do with Willis’s suggestion that pressure should be expected to drop because “water vapor makes air lighter”. Finally, it contradicts the observation reported in the paper. Explanations that deny the occurrence of observed phenomena aren’t good explanation of them. But the reason it’s a bad explanation simply is that it’s irrelevant to the case at hand. We aren’t talking about storms and tropical depressions at all — just ordinary surface evaporation below the dew point, with no release of latent heat.
“We aren’t talking about storms and tropical depressions at all — just ordinary surface evaporation below the dew point, with no release of latent heat”
The very first illustration in the OP shows precipitation.
I guess you don’t know that involves the release of latent heat of vaporization.
You’re a retard.
.
Even the OP clearly states (my bold):
What the phuck is your major malfunction?
Oh I know. You’re pulling my leg. No one is that willfully stupid. Haha. Good one. You got me.
Just to be clearer: it’s important to distinguish two phenomena. If water vapor increases over some wide area, as I explained, the immediate result of the mass increase in the atmospheric column is an increase in pressure at ground level. This also causes the more humid water to become more buoyant. So, eventually, dryer surrounding air will replace it and convection will commence. Whether or not convection will proceed depends on the temperature gradient and dew point. But the initial effect from the evaporation is an increase of the atmospheric pressure at ground level.
David, this part of the paper may explain things better than I am able to:
“Precipitation depletes atmospheric moisture, while evaporation replenishes this loss. Since condensation depends on the vertical velocity of the ascending saturated air it can theoretically occur at an arbitrarily high rate, while the rate of surface evaporation depends on solar radiation flux and is limited. Consider an area with a length scale exceeding 103 km (and neglect for now any exchange of air with the surroundings). If the air is moist and rises high in one place and descends in another within the considered area (a deep convection event), this will lead to the reduction of mean pressure in the area owing to the removal of precipitated moisture in the ascending branch from the atmospheric column. This process will end once the atmosphere has become sufficiently dry. The next major condensation/precipitation event will not occur until water vapor has accumulated in the atmosphere beyond the critical limit. Such accumulation occurs via evaporation, which is a relatively slow process. This gradual build-up of moisture will be accompanied by gradual rise of surface pressure in the area reflecting the growing mass of the atmospheric column. Thus, most intense precipitation in our area will occur when the CWV and, consequently, the mean surface pressure in the area are at their highest. Rainless days will occur when CWV and pressure are diminished by precipitation, and will be characterized by lower pressure.”
Still furiously digging that hole deeper trying to cover up a brain fart of truly monumental proportion I see.
High pressure regions are associated with clear sky and dry air.
Low pressure regions are associated with moist unstable air.
Evaporation makes air moist.
Get your head out of your ass and connect the dots.
Such a level of bad faith is disquieting. What part of (not my words): “This gradual build-up of moisture will be accompanied by gradual rise of surface pressure in the area reflecting the growing mass of the atmospheric column.” don’t you understand, or why do you think it contradicts the laws of physics? This is what Willis also didn’t understand. Can’t you address *this* topic and not change the subject to tropical depressions or whatnot? Do you think Douglas Sheil and his five co-authors all are crackpots?
Springer quoted: “This highlights how the intense evaporation from forest creates low pressure.”
This quote relates to a different phenomenon exhibited over a different time-scale. The pressure increases (because of evaporation) *before* it decreases again (because of rainfall) as the authors explain very well. Did you ever stop to wonder why the authors would flatly contradict themselves in the very same paragraph of their paper or are just intend on ignoring the quote that I provided and which Willis commented on?
“The very first illustration in the OP shows precipitation.”
So what? Do you think the author is debarred from discussing any phenomenon that isn’t depicted in the first illustration of his blog entry? The passage that puzzled Willis doesn’t relate to this illustration. It relates to what happens later when “This process will end
once the atmosphere has become sufficiently dry…” and when “Such accumulation occurs [b]via evaporation[/b], which is a relatively slow process. This gradual [b]build-up of moisture[/b] will be [b]accompanied by gradual rise of surface pressure[/b] in the area reflecting the growing mass of the atmospheric column.”
If it may help, and since you seem to prefer pictures, maybe you should have a look at the *third* figure, directly above, and directly relating to, the statement that puzzled Willis and that astonishes you. You’ll notice that there is no condensation of rainfall depicted in *that* case — only evaporation is taking place.
…condensation [or] rainfall…
Holy Holes, Batman. He’s still digging.
Why don’t you ring up the atmospheric physics department and Texas A&M University and tell them they got it all wrong, dopey?
http://atmo.tamu.edu/weather-and-climate/weather-whys/701-low-pressure-systems
Maybe if you highlight which bits below you don’t, won’t, or can’t understand…
http://www.weatherwizkids.com/weather-forecasting.htm
What is a High Pressure System?
A high pressure system is a whirling mass of cool, dry air that generally brings fair weather and light winds. When viewed from above, winds spiral out of a high-pressure center in a clockwise rotation in the Northern Hemisphere. These bring sunny skies. A high pressure system is represented as a big, blue H.
What is a Low Pressure System?
A low pressure system is a whirling mass of warm, moist air that generally brings stormy weather with strong winds. When viewed from above, winds spiral into a low-pressure center in a counterclockwise rotation in the Northern Hemisphere. A low pressure system is represented as a big, red L.
L
So every Meteorology 101 text newer than dirt defines a high pressure system as whirling mass of cold dry air and a low pressure system as a whirling mass of warm moist air.
So how does cold dry air become warm moist air? I’ll give you three chances to say “evaporation is what makes dry air into moist air”. Try real hard. It’s not rocket science.
“Why don’t you ring up the atmospheric physics department and Texas A&M University and tell them they got it all wrong, dopey?”
Because I myself supplied to you this *very* explanation (which I learned in the Feynman Lectures on Physics over 20 years ago), and pointed out that it relates to a *different* process than the one under discussion and described in the blog post — which takes place *before* (and over a shorter time scale than) the creation of a low pressure system. In your view, it’s just *inconceivable* that under some specific conditions of surface evaporation atmospheric pressure at ground level could increase over any time period *before* it drops again, right? Douglas Sheil and his co-authors got it all wrong? What mistake did they make? You think any degree of evaporation must lead to the creation of a convection cell and to condensation instantaneously and irrespective of the dew point?
“What is a High Pressure System?
A high pressure system is a whirling mass of cool, dry air that generally brings fair weather and light winds. […]
What is a Low Pressure System?
A low pressure system is a whirling mass of warm, moist air that generally brings stormy weather with strong winds.[…]”
We aren’t talking about a “whirling mass of air”, and hence we aren’t talking about a low or high pressure *system* at all. We are talking about a rather stationary mass of relatively dry air over a large forest (after the occurrence of precipitation has dried the air up). There is no low or high pressure system (no whirling mass of air) passing over and there hasn’t been any significant convection occurring *yet* as a result of evaporation. This is the transient state of affairs that we are discussing.
What did the authors get wrong?
Diluting a gravitationally confined column of gas with a lighter gas always results in less mass in the column if temperature is held constant.
I wrote at the very beginning that what Willis missed is a change in temperature associated with evaporation. Evaporation moves sensible heat into latent of heat vaporization. This cools the air. It isn’t held at a constant temperature as the lighter gas is added to the column. Colder air is denser. This creates a higher pressure until condensation occurs which reheats the air, it becomes less dense, and pressure falls.
It’s the change in temperature Willis missed. He was absolutely 100% correct that more water vapor at constant temperature lowers pressure which is why high pressure systems are cold dry air and low pressure systems are warm moist air. Over and over you fail to grasp this fundamental tenet of meteorology.
This is obviously way the phuck over your pay grade.
And it actually does whirl. It’s physically impossible for the coriolis effect to disappear as lighter vapor rises off the forest canopy. Just because it isn’t a funnel cloud doesn’t mean it isn’t turning as it rises. Coriolis forces don’t get suspended. Ever. Unless the earth stops spinning. Write that down
“Coriolis forces don’t get suspended. Ever. Unless the earth stops spinning. Write that down.”
What if a buoyant parcel of air rises at the equator? Will it be deviated northward or southward? Will it choose at random?
David Springer explained:
“What did the authors get wrong?
Diluting a gravitationally confined column of gas with a lighter gas always results in less mass in the column if temperature is held constant.”
I see! Mixing some amount of a light gas with a heavier gas can reduce the total mass of the gas. Some of the individual molecules probably are losing mass in the process. Lavoisier must have overlooked that possibility. Thank you!
“I wrote at the very beginning that what Willis missing is a change in temperature associated with evaporation. Evaporation moves sensible heat into latent of heat vaporization. This cools the air. Colder air is denser. This creates a higher pressure until condensation occurs which reheats the air it becomes less dense and pressure falls.”
Yes, I got it now! The weight of the total air column changes! That must be for the same reason why one pound of lead is so much heavier than one pound of feathers! Thank you!
“This is obviously way the phuck over your pay grade.”
Yes. I hadn’t realized how far behind I was. Thanks for the enlightenment. I feel like I am now a better amateur scientist.
Pierre-Normand wrote: “What if a buoyant parcel of air rises at the equator? Will it be deviated northward or southward? Will it choose at random?”
Oops… eastwards of course (thought not much). Conservation of angular momentum. Self-owned. I should have asked about the poles, though there aren’t very many forests there.
Re Roy Spencer: The average temperature of the continental US really has not changed for the past 30 years. No wrongheadedness about it. That’s the data. But CO2 has climbed and the US is getting greener which is also revealed by the data. Perhaps that is what accounts for any plant or animal distribution changes.
“The U.S. lower-48 surface temperature anomaly from my population density-adjusted (PDAT) dataset was 1.26 deg. C above the 1973-2012 average for May 2012, with a 1973-2012 linear warming trend of +0.14 deg. C/decade” — Roy W. Spencer on WUWT.
Who do you think you’re fooling but clipping out of context and not providing a link, Pierre? Does that work among the rubes where you live?
http://wattsupwiththat.com/2012/06/08/uah-continental-us-temperature-for-may-2012-1-26-deg-c/
With the whole article in view one can easily see the next paragraph:
0.14C/decade trend is almost statistically insignificant. 0.10C/decade is considered statistically insignificant. 0.2C/decade would be mildly concerning if it wasn’t mostly happening in the winter in high latitudes where modest warming quite welcome by the native flora and fauna. Surviving snow and ice for 4 months is a challenge at best for most organisms. But the average global troposphere trend since 1950 is only 0.12C/decade so there’s really nothing to be alarmed about and probably won’t be for the rest of the 21st century at this rate. Presumably technology will continue to advance and 100 years from now we’ll have far less expensive carbon neutral energy supply and different things to worry about than greenhouse gases.
“The corresponding USHCN anomaly computed relative to the same base period was +1.65 deg. C, with nearly double my warming trend (+0.27 deg. C/decade).” — Roy W. Spencer on WUWT
Data up 30%, trend up 100%?
===============
Spencer is comparing May 2012 to the base period and also computing the trend over the base period. Two different things. The halving of the trend is a result of his adjustments.
c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples
“c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples”
Beliefs are so subjective, aren’t they?
It’s almost like they aren’t scientific.
Andrew
Mosh said
‘c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples’
That’s because the latter can be proven and demonstrated to be correct whilst the other is supposition. Go figure. (or write it down)
tonyb
Steven Mosher you write “c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples”
I thought I was a skeptic/denier, and I believe in BOTH of these. The question to me is how MUCH warmer does added CO2 make the world. My claim is that any warming is negligible.
actually tony neither can be proven.
You see tony, just because we have lab experiments that show plants
( well some plants, under some conditions) will increase their growth when there is more C02, ( like we have lab experiments with c02) and just because we have evidence that c02 has gone up and greenness has gone up, you havent proved that the greeness wasnt the result of something else.. same way warmists could point to warming increasing ( about 1C) and skeptics say.. you havent proved it isnt cosmic rays or unicorns.
Consider the STRUCTURE of the arguments.. forget the content ( here you learn the wonders of philosophy) look at the structure.
C02 in the lab with plants: more c02 more green
Plant Biology: we understand why
In the field. We see increasing c02 and increasing green
The argument hangs together
C02 in the lab with IR transmission: More C02 = less transmission
C02 physics: we understand why
in the feild: we see increasing c02 since 1850 and increasing temps
What do skeptics do in case 1.
A. Do they question the lab methods? nope
B. do we have skydragons of plant biology? no
C. do we have skeptics questioning the field methods of collecting
and processing greeness data? no
D. do skeptics ever argue that something else might be making the
planet green? No.
What do skeptics do in case 2.
they question everything.
Now from an epistemic view the structure of the arguments is exactly the same. Some core science, studied in the lab, with field observations.
The only difference?
Joshua could explain.
This is selective skepticism.
Or better
Look the planet has been greener before in the past when there was less c02, therefore we dont need c02 to explain the amount of greenness today.
haha.
there is nothing unprecidented about the amount of greenness today, therefore its all caused by natural variation.
plus, c02 is trace gas, it cant change the amount of plant growth.
haha.
See what happens when skeptics say they believe something
Skeptic says he believes increased c02 causes plant growth
Then simply use the same skeptical arguments against c02..
trace gas argument
natural variation argument
other things cause plant growth arguments
you havent proved it wasnt something else
Hell ITS THE SUN STUPID.. its the sun that causes plants to growth
haha
fun exercise.
This is why it is more important to understand what people believe rather than what they doubt
Steven, people need reason to doubt – they don’t need reason to believe.
Beliefs are – by definition – irrational.
Tony
In response to Mosher’s comment:
“C02 climbs and the world gets warmer
C02 climbs and the world gets greener
skeptics believe in causation in only one of these examples”
And your reply:
“That’s because the latter can be proven and demonstrated to be correct whilst the other is supposition.”
I’d tend to agree that neither can be “proven” to be due to higher CO2 concentrations. Do you really believe that higher levels of CO2 will not lead to it being somewhat warmer than it would have been if CO2 concentrations were lower???
Mosher, nobody is saying we should increase our CO2 emissions so that the world gets greener. We do it for energy and the greening is just a bonus. Assuming humans can significantly affect atmospheric CO2 with their emissions, which I don’t believe.
Rob Starkey
There have been numerous controlled tests as well as even more greenhouse operations, which demonstrate that plants grow faster at higher CO2 levels. They are also more resistant to droughts at higher CO2 concentrations.
This is more pronounced for C3 type plants (which include most human crop plants) than for C4 types (corn, grasses plus most common weeds), but both types benefit from increased CO2 levels.
So this is an empirically established fact.
In addition, there are satellite images showing that plant life on the planet is increasing.
Whether or not higher CO2 concentrations will really result in a perceptible increase in global average temperatures in our climate system due to the greenhouse effect and, if so, how much, is still very much an open question.
The AGW hypothesis is well thought out, is based on theoretical “first principles” including laboratory data on the absorption characteristics of several GH gases (incl. H2O and CO2), but it has not yet been either falsified or validated in our atmosphere by empirical evidence (from actual physical observations or reproducible experimentation). It remains an uncorroborated hypothesis – no more.
Max
“There have been numerous controlled tests as well as even more greenhouse operations, which demonstrate that plants grow faster at higher CO2 levels.”
Not true.
Those tests were all under lab or field conditions, not real world conditions that include the complex interactions between animals, insects and plants.
As such they cannot be extrapolated. As Jim Cripwell will agree the effect of elevated CO2 on plants (in the real world) is indistinguishable from zero.
Max- I am familar with how CO2 impacts plant growth, but in the actual system I do not think you would be able to “prove” that any increased plant growth was due to CO2. There would be to many variables to “prove” that the change in 1 was the cause of the change in the plants growth.
Now if someone claimed there was a high probability that it aided in increased plant growth, or some other wording short of proof, then sure.
lolwot- Higher CO2 levels can be demonstrated to increase plant growth. There is every reason to believe that the higher levels will lead to the same in the overall system. It simply can not be PROVEN to be due to that cause.
Mosh
Plants metabolise co2 and is integral to their growth
http://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108
Co2 causes warming. Does co2 cause warming over and above What we have seen in the past at a constant 290ppm? The earth has been warmer and colder at 290ppm suggesting that adding more has limited effect.
You need to demonstrate otherwise .
Tonyb
Tony co2 is integral to the retention of lwir. Same as it is integral to plant growth.
And yes the world was greener with less co2. Therefore…
Phatboy is that your belief?
Edim
My concern is the structure of argument and warrented beliefs
Is a “warrent” the dumbass I can’t spell version of “warrant” by any chance?
Lolwot gets it.
Heh, structurally symmetric, naturally skewed. Very funny, moshe.
===========
Much of the world is greening – http://www.csiro.au/Portals/Media/Deserts-greening-from-rising-CO2.aspx – not sure that’s actually a good thing.
The world warms and cools – damn sure it isn’t predictable.
“c02 is trace gas, it cant change the amount of plant growth”
CO2 is trace gas because it does change the amount of plant growth.
“What do skeptics do in case 2.
they question everything.”
What would be really funny would be to see lolwot and Mosher actually apply the logic of lolwot’s parody of Springer to CAGW honestly.
(Starting by not falsely claiming that “skeptics” deny the GHE under controlled, laboratory conditions would be a nice start.)
What is hilarious is to see lolwot pointing out “the complex interactions between animals, insects and plants,” and equating that with complex interaction of the atmosphere, oceans, land, solar insolation, water vapor, convection, clouds, etc., etc., ad infinitum.
I will accept that the reaction of plants to CO2 in the laboratory might well be impacted by the factors lolwot suggests. And if someone were proposing to reorder the entire world energy economy on the basis of predictions from those limited laboratory experiments, I would view those arguments with the same skepticism I do CAGW. And for the same reasons.
Mosher claims to be a lukewarmer, but comments like this, and his position as the Climate Etc. obscurantist in chief, suggest otherwise. And lolwot is simply a true believer from the start. So I guess logic should be expected to be in short supply.
Smiffsomian says “It has been well established that rising CO2 will stimulate plant growth.”:
http://www.serc.si.edu/labs/co2/co2_overview.aspx
They could be lying.
Skeptics of freaking hysterical global warming alarmism are under no obligation to be skeptical about every freaking thing.
This seems to be a silly day for Mosher.
Mishap at a meeting of the CAGW faithful:
http://www.liveleak.com/view?i=fad_1397476880
I think that is lollie stumbling and getting singed.
Mosh
your 8.56.
You haven’t really answered my comment with physics.
I said that (during the Holocene) the world has been warmer than today and cooler than today with co2 at pre industrial 290ppm.
This suggests that above 290ppm any changes in temperature are difficult to discern. You therefore need to demonstrate- using physics- that adding more co2 above this level will significantly increase temperatures above the past values, because to date that does not appear to have happened.
tonyb
Lolwot and Mosh run circles around the deniers, who can not comprehend that they are being made fools of.
—-
Consiider the mountain pine beetles.
Which attack Canadian and Rocky Mountain ponderosa, lodgepole, Scotch and limber pine forests.
Elevated winter temperatures in Canada are not killing off the populations.
http://www.ec.gc.ca/adsc-cmda/8C03D32A-4B97-487A-A03C-F46F91A12F37/CTVB_Winter_2013_temp_graph_E.jpg
Change of +3C in winter temperature since 1950 !
What to make of that?
Do Canadian citizens such as Cripwell ignore this information? Do they continue to claim that “any warming is negligible” ? Yes they do.
Web
your 2.40. No doubt Canadian citizens such as Jim Cripwell are aware of the Hudson Bay and Board of trade journals which amply illustrate great variations in temperature . For example.
“The great variations in ice amounts and warmth and cold, is also recorded in the following, condensed from the records of the Hudson Bay company, which appear to demonstrate that climate change is not a new phenomena.
“Over the fifteen years between 1720 and 1735, the first snowfall of the year moved from the first week of September to the last. Also, the late 1700s were turbulent years. They were extremely cold but annual snow cover would vary from ‘extreme depth’ to ‘no cover’. For instance, November 10th 1767 only one snowfall that quickly thawed had been recorded. June 6, 1791 many feet of snow in the post’s gardens. The entry for July 14, 1798 reads ‘…53 degrees colder today than it was yesterday.”
The following is a modern day reconstruction of sea ice around Newfoundland from 1810 to 2000 demonstrating the huge variability (which compares with modern times) and perhaps illustrates the 60/70 year arctic oscillation amongst other cycles. (Scroll down to the heading “195 years of sea ice ice off Newfoundland”)
http://www.socc.ca/cms/en/socc/seaIce/pastSeaIce.aspx
tonyb
WHUT writes “Do Canadian citizens such as Cripwell ignore this information? Do they continue to claim that “any warming is negligible” ? Yes they do.”
Sometimes I wonder why I bother to reply; as this discussion is so off topic. But, once again, I get misquoted. Warmists don’t seem to have any interest in what skeptics actually write. They just seem to believe that we are always just plain wrong.
Of course global temperatures vary; natural causes provide significant changes in temperature. Is there any measured evidence at all that any change in temperature is caused by adding CO2 to the atmosphere from recent levels? Absolutely none whatsoever
The world is getting greener?
What is ‘green’? Is there an agreed definition of ‘green’??
What length of historical record do we have for measurements of ‘green’?
Michael writes “What length of historical record do we have for measurements of ‘green’?”
Basically since satellites started taking colored pictures of the earth; around 1979. I know a little about this subject, as I convert computer pictures into counted cross stitch patterns. Each picture consists of a number of pixels. Each pixel is defined by the RGB value; R red G green, B blue. These are numerical values between 1 and 256. There are generally agreed RGB values which are considered to be “green”. All people have done is compared how many green pixels that there are in modern pictures compared with those taken of the same area in the 1980s. This data shows there are more green pixels now than there were 40 years ago. There can be a numerical comparison.
Jim,
You might have the wrong end of the stick there.
And just a few decades of data? Oh dear.
Good one, moshe. You got Michael as well as lolwot. That’s tougher.
==========
Mosher, Michael and lolwot.
The Trilateral Commission of Climate Etc.
Andrew
Jim Cripwell:
”
Each pixel is defined by the RGB value; R red G green, B blue. These are numerical values between 1 and 256.
”
0 and 255, actually.
”
This data shows there are more green pixels now than there were 40 years ago. There can be a numerical comparison.
”
That’s because most of the world has moved on from 640×480, 8-bit VGA.
Today, we can watch the rapid destruction of tropical forests in beautiful 1920×1080- with bit depths of 30 bits (1.073 billion colors) or even 48 bits (281.5 trillion colors).
Not only that, but one must remember to calibrate the data for the remarkable increase of astro-turf in the satellite record over the last 4 decades.
Heh, Jeb, too. Well, guys and dolls, Nature finds it a lot easier to demonstrate that CO2 is a greening control knob than it is a warming control knob. Just why that is, I’m unsure, ‘cuz it gets a little recursive when warming is also a greening control knob. But moshe’s jeu de syllogisme shows great dexterity among the alarmists at contorting themselves to find a place to touch ground.
=========
There is a consensus among the scientific satellites. The earth is getting greener and it ain’t getting any warmer. And the pause is killing the cause.
Kim, do you think it would be fair if we called these people global greening deniers?
Don, what is being denied are the manifest and manifold benefits of greening and warming. In the rush to invoke fear and guilt, someone forgot to check a box, and look at the waste from the haste.
=========================
Michael | April 16, 2014 at 8:19 am |
The world is getting greener?
What is ‘green’? Is there an agreed definition of ‘green’??
What length of historical record do we have for measurements of ‘green’?
————
What length of historical record do we have for measurements of temperature? (Not proxies, not poorly distributed and sited thermometers, but consistent, coverage in terms of same sensor, uniformly distributed.
Steven Mosher | April 15, 2014 at 2:19 pm |
c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples
———
One has been measured in experiments in volumes, what, 10 orders of magnitude larger than the other.
One is used commercially, an indication that individuals are willing to put their money where the science is I order to increase their profits.
The other… well, we do have that experiment that said if all,other things are equal then the net change in IR is…
Steven Mosher | April 15, 2014 at 3:53 pm |
“C02 in the lab with IR transmission: More C02 = less transmission
C02 physics: we understand why in the feild: we see increasing c02 since 1850 and increasing temps”
I looked for an experiment confirming that air temperature rises in higher CO2 environment with no change in illumination and found nothing but amateur hacks by Mythbusters and Bill Nye the Science guy.
Maybe you know of something peer reviewed and replicable?
There is the legitimate argument that CO2 is both more absorptive and more emissive at the same time. Real world devices that measure CO2 concentration in ambient air do it by measuring the change in power in the absorption band not the temperature of the sample so that’s no proof.
IPCC AR5 WG1 presents this table on the flows of carbon. We see that the recent residual land sink after removal of effects of land use change is -2.5±1.3 PgC/yr. That seems to indicate that higher CO2 concentration has led to a significant extra growth. Much of the carbon ends up in soil, but that is likely to require extra growth as well.
How much of Trenberth’s supposedly ‘missing heat’ is represented by that 2.5 PgC/yr? Bear in mind that this feedback will have a rising effect as the CO2 rises.
========
Nevermind the ocean where the carbon sinks into anoxia.
========
You can’t assume that just because organic (reduced) carbon sinks into anoxic conditions it won’t come out. That’s probably the usual case, but the sulfur cycle is capable of transporting oxidizing potential between depths with oxygen and detritus undergoing anaerobic respiration, which in turn can produce CO2 which is then transported back to aerobic depths
Producing the carbon bearing material of plants and soil from CO2 takes roughly as much net energy as burning the same amount of fossil carbon releases, perhaps a little more. Thus about one third of the heat released from burning fossil fuels ends up there. These amounts are close to negligible in comparison to the forcing from additional CO2 in the atmosphere.
Thanks, Pekka. So it’s clouds for now, negative carbon sink feedback sits on the bench waiting for the starters to get tired.
============
Thanks, AK, for the subtlety, but the presence of fossil fuels demonstrates the power of the feedback, nicely documented in paleontology and petroleum geology.
===============
David Springer:
”
I looked for an experiment confirming that air temperature rises in higher CO2 environment with no change in illumination and found nothing but amateur hacks by Mythbusters and Bill Nye the Science guy.
Maybe you know of something peer reviewed and replicable?
”
So – You did a Google-search?
And it failed to enlighten you?
There’s an amateur hack.
Anyway: Just adding CO2 to an “environment” under illumination will not increase its temperature. Conversion from shortwave to longwave photons is needed. This is what happens when stuff absorbs visible light and then radiates in infrared. Like when there is a planetary surface in the path of sunlight.
In spite of the paucity of your Google hits, many scientists have worked this already.
Try this:
http://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf
”
Databases of spectral-line properties lie at the founda-
tions of all calculations of IR radiative transfer in gases. The HITRAN database, culled from thousands of meticulously
cross- validated, published spectroscopic studies, provides
line properties for 39 molecules; it has been extensively used for applications across engineering and atmospheric sciences.
The database is freely available at http://www.cfa.harvard
.edu/hitran. A simple, flexible Python- language interface to
HITRAN is included in the online software supplement to
reference 5, available at http://geosci.uchicago.edu/~rtp1/
PrinciplesPlanetaryClimate.
”
Now – Please show everyone your evidence that HITRAN is wrong.
Hint: Google won’t help. You might even need to do some actual science experiments.
Reverend.
Springer wouldn’t have a clue about HITRAN.
ex- games programmer. that’s all you need to know about Springer.
Uh no. Game programmer was a fun and lucrative hobby. My forte was hardware and firmware development. I was a BIOS coder in laptop and desktop motherboard produce design at Dell.
https://www.google.com/search?tbo=p&tbm=pts&hl=en&q=david+springer+dell+usa
I got bored and dabbled in patents my final year there. Four or five were granted a few years after I left the company. I left a cool half million on the table in unvested stock options from those patents because I got too bored to wait around for them to grant and back then a half million didn’t seem like much. Microsquishy offered me that much to quit Dell in 1998 and go to work for the Game Zone and but I had to turn them down too. Good times. I bailed just before the dot-com bust a year later in 2001. It hasn’t really been the same since then, ya know? In 1999 I began getting back to my roots clearing virgin forest on a lake shore with a chainsaw and tractor prior to building a home on it. Fun and satisfying but in a different way than slinging integrated circuits and churning out machine code which I’d been doing for the previous 20 years.
Better link to my granted patents.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=springer&FIELD1=INNM&co1=AND&TERM2=dell+usa&FIELD2=ASNM&d=PTXT
I’m particularly fond of “computer system including display control system” which I devised (sole inventor which is rare at big corporations) on a flight back from Taiwan seated next to a guy from Raytheon or some military contractor who was part of the development team for a cold cathode electron beam flat panel. You know like typical small talk for engineering geeks. They’d got them as big as quarters and very expensive but they were super high contrast, high resolution color, and consumed zero current on black pixels and increasing current as the brightness of individual pixels went up. No backlight. Cost wasn’t really an object for a military rifle scope but I figured if they ever got cheap and big they’d be really cool for clever battery-saving techniques on laptops. So I patented an application for them as soon as the jet lag wore off.
Reverend, you write “Now – Please show everyone your evidence that HITRAN is wrong.”
Several years ago, I went over this with Pekka. I admit my understanding of this issue is limited, but it is my understanding that Hitran, Modtran, etc were not written to calculate the change in radiative forcing as more CO2 is added to the atmosphere. They were written for a similar, but not the same, sort of calculation.
So it seems to me that the shoe is on the other foot. It is not up to us skeptics to show that Hitran is wrong; it is up go the warmists to show that Hitran is right. All we get in Myhre et al 1998 is “Three radiative transfer models are used”. It has always struck me that this is a somewhat inadequate explanation of what was calculated.
Mosher: c02 climbs and the world gets warmer
c02 climbs and the world gets greener
skeptics believe in causation in only one of these examples
So far, the second has had some direct experimental tests, via adding CO2 to crops and copses, and finding that the added CO2 causes increased growth. Overall the picture is complex, what with changing temps and rainfalls over large regions.
The first is much more complex, as extra downwelling radiation from extra CO2 produces more evaporation and more cloud cover, much reducing any warming effect; and no direct experimental test of CO2 increase on regional warming has been carried out. Over the past 17 years there is not even an association between increased CO2 and increased global mean temp: Trenberth’s “missing heat” “travesty”.
On the second, the science seems to be supporting a causal link; on the first, the picture is growing, ahem, cloudier and cloudier.
The Very Reverend Jebediah Hypoteneuse: Try this:
http://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf
”
Databases of spectral-line properties lie at the founda-
tions of all calculations of IR radiative transfer in gases. The HITRAN database, culled from thousands of meticulously
cross- validated, published spectroscopic studies, provides
line properties for 39 molecules; it has been extensively used for applications across engineering and atmospheric sciences.
The database is freely available at http://www.cfa.harvard
.edu/hitran. A simple, flexible Python- language interface to
HITRAN is included in the online software supplement to
reference 5, available at http://geosci.uchicago.edu/~rtp1/
PrinciplesPlanetaryClimate.
”
Now – Please show everyone your evidence that HITRAN is wrong.
Thank you for the link. The “missing link” in the climate argument is showing that increasing CO2 will produce increasing atmospheric or surface temperature, given the climate as it is now. If increasing CO2 causes increasing downwelling LWIR, then it will cause increased vaporization from the non-dry areas of the surface; the new energy transfer into new vapor may be much greater than the new energy transfer into sensible temperature rise — other things being equal. Hence the scientific hypothesis generating so much interest and research that increased CO2 may result in increased cloud cover and resultant lower mean global temp.
David Springer
And you won’t, because there is nothing that is based on empirical evidence in our atmosphere.
The Reverend and Mosh can bluster all they want to, but they cannot cite such a physical observation or actual reproducible experiment.
Max
Hitran is a collection of data on radiative properties of molecules. Such data is equally applicable in all applications that involve radiative interaction of gases of atmosphere.
MODTRAN is one of many models that perform similar calculations of transmission, absorption and emission of IR in gases. Very many such models are verified as accurate enough for the particular applications where they are used. Neither Hitran nor those models are a source of much uncertainty, they do their part well enough.
Going further the other models needed are not anymore as well understood or thoroughly tested.
“One has been measured in experiments in volumes, what, 10 orders of magnitude larger than the other.”
In both cases controlled conditions and experiments show rising CO2 causes both warming and greening in those controlled conditions.
For warming you (collective) use the fact it is just controlled conditions as an excuse to pour doubt on the idea that rising CO2 causes global warming. But you apply a different standard for global greening. There you are happy to just extrapolate the controlled conditions to the entire globe.
Your bias is showing.
Observations show both greening and warming of the world. You unquestionably accept the greening observations, but tirelessly pick at the temperature measurements trying to justify doubt in them.
Your bias is showing.
You claim that the world has greened and jump to the conclusion that therefore CO2 must be the cause. But you abhor the same logic being applied to the cause of the warming.
Your bias is showing.
Kim writes: “Nature finds it a lot easier to demonstrate that CO2 is a greening control knob than it is a warming control knob”
I very much doubt you’d be able to justify that statement with evidence.
What I think is that you’ve been trained to deny the science for the link between CO2 and warming but allowed (or even encouraged) to accept the science behind the link between CO2 and greening.
I personally go with what the scientists have reported from their studies on both subjects.
lolwot, you’re still fooled. Matthew Marler, @ 3:40 PM today, above, was most lucid.
=========
lolwot: For warming you (collective) use the fact it is just controlled conditions as an excuse to pour doubt on the idea that rising CO2 causes global warming. But you apply a different standard for global greening. There you are happy to just extrapolate the controlled conditions to the entire globe.
Consider the hypothesis that increased CO2 causes increased plant growth: that has been tested in field trials.
Consider the hypothesis that increased CO2 causes increased atmospheric warming: no relevant field trial of that hypothesis has been done. Consider the more specific hypothesis that an increase in downwelling LWIR on the sea surface will cause warming of the surface and the air column above it: no relevant field trial of that hypothesis has been conducted either. In both cases, there are legitimate reasons to doubt the causal link.
Is anybody claiming that all, or a particular fraction of increased agricultural productivity or net primary productivity of intact forests is caused by CO2 the way some people claim that all or half of global warming since the LIA is due to anthropogenic CO2? If so, be sure to let us know, so I can throw doubt on that claim as well.
If there is a bias you have not pointed it out. There is just a narrower claim in the CO2-growth case and actual field experiments. For the CO2 – climate link the claim is more extreme, with a baseless claim of precision, and absence of a directly relevant climate trial.
Thanks, Matthew, clearer and clearer. But, heh, I claim that. And since warming is also a greening control knob I claim, at the 95% confidence level, that the majority of the greening since, uh, Abbey Whenever, has been anthropogenic.
===========
Evidence for the warming effect of CO2: it has been warming for a century and globally.
Evidence for the greening effect: how long, a few years(?), and where do you have to look for it? And what about the areas that are browning instead? Have you even looked for those, or would they be a blow to your confirmation bias?
Gad, moshe, Jim D, too.
Back to an earlier question. Why is it so much easier for Nature to demonstrate that CO2 is a greening control knob than to demonstrate that CO2 is a warming control knob. I think the answer is that plants can only do one thing with increased CO2 and the oceans, land and atmosphere can do a plethora of things with extra Watts per meter squared. As Ellison puts it, there are enormous energies cascading through huge systems, with much opportunity for turbulence causing all sorts of expressions other than heat.
========
Marvelous Anthropogenic Global Greening, it’s MAGGic.
=================================
Global greening deniers should be jailed.
“Is anybody claiming that all, or a particular fraction of increased agricultural productivity or net primary productivity of intact forests is caused by CO2 the way some people claim that all or half of global warming since the LIA is due to anthropogenic CO2? If so, be sure to let us know, so I can throw doubt on that claim as well.”
That is a bit disingenuous. We have had people like kim unquestionably promoting the idea that not only is global greening happening, but it’s happening – and will continue to happen – because of rising CO2.
Which is completely at odds with the approach you take to CO2 and warming.
It’s so easy to question the accuracy of global greening measurements, question the cause of greening and question the evidence of CO2 causation of greening on a global scale over decades. The elephant in this room is that none of you voiced such skepticism.
It seems your use of skepticism is merely a stick to bash particular parts of science you don’t care much for. What else can be the explanation for the discrepancy?
Jim Cripwell:
”
It is not up to us skeptics to show that Hitran is wrong; it is up go the warmists to show that Hitran is right. All we get in Myhre et al 1998 is “Three radiative transfer models are used”. It has always struck me that this is a somewhat inadequate explanation of what was calculated.
”
Jim, you do not get to summarily decide who bears the burden of proof in science, or what is an “inadequate explanation” – by commenting on a blog.
Working scientists do, by choosing to use HITRAN, or by publishing a study of spectral properties that adds to the database.
Feel free to reject HITRAN because you suspect it is “wrong”.
Your incredulity is not really a problem for science: there are thousands of published studies of radiative transfer – thousands of researchers have performed thousands of cross-validate experiments on the topic.
Guess what? HITRAN works.
http://www.cfa.harvard.edu/hitran/molecules.html
Since you’ve apparently read Myhre, maybe you’ll take a look at these…
L. S. Rothman et al., J. Quant. Spectrosc. Radiat. Transfer
110, 533 (2009).
R. T. Pierrehumbert, Principles of Planetary Climate, Cambridge
U. Press, New York (2010)
“Jim, you do not get to summarily decide who bears the burden of proof in science”
He does. He has the right and the duty to use his own judgement.
Andrew
Reverend, you write “Guess what? HITRAN works.”
I know HITRAN works. I have said HITRAN works. I agree HITRAN works.
But HITRAN works if and only if, you ask it the right question. Now the people who use HITRAN routinely, I am sure, ALWAYS ask HITRAN the right questions. What I do not know is this. Is asking HITRAN to calculate the change in radiative forcing for a doubling of CO2, asking the right question? Is HITRAN capable of answering this question? The peer reviewed literature is silent on the issue.
All I have is Pekka’s assurance that HITRAN is, indeed, capable of answering the question. I must accept this, as he knows far more about the subject than I do, But I am deeply suspicious, and I would love to have a published paper which describes WHY HITRAN is capable of calculating the change in radiative forcing for a doubling of CO2..
Jim Cripwell:
”
The peer reviewed literature is silent on the issue.
”
No. It isn’t. Maybe your research skills are lacking.
”
But I am deeply suspicious, and I would love to have a published paper which describes WHY HITRAN is capable of calculating the change in radiative forcing for a doubling of CO2.
”
Jim Cripwell is deeply suspicious!
Another damning comment on a blog!
Whatever will science do?
http://asd-www.larc.nasa.gov/~kratz/ref/p33jqsrt.pdf
http://pubs.giss.nasa.gov/abs/ha01110v.html
And Jim, if HITRAN doesn’t meet your exacting standards, you can always look at the other radiative transfer databases – some linkies here:
http://www.cfa.harvard.edu/hitran/other.html
See how that works? Reproducible, cross-validated, experimental evidence.
Reverend, you write “See how that works? Reproducible, cross-validated, experimental evidence.”
I have glanced at the references you gave me, and from what I can see they do not address my concerns. I have neither the time nor the inclination to wade through irrelevant references. Could you direct me to the specific parts of any reference which show why HITRAN is a suitable model to assess the change on radiative forcing for a doubling of \CO2?
What about grass/herbaceous vegetation? Would that type also have a cumulative effect on climate? I know some grasses have fairly deep roots, but then again above-ground portions can die in extreme water stress and regrow when the stress is relieved, something not commonly seen in trees.
I’m a grad student currently studying vegetation effects on the water balance, and climate/landscape controls on vegetation, but haven’t yet considered it in the other direction. This is very interesting.
Hi Tyrone
certainly herbaceous vegetation and its behaviour (when it leafs and its water use) will impact local temperature, atmospheric moisture etc. Generally such effects will be less than those from tree cover simply because less water is being evaporated. There are also likely to be various particles and chemicals that are also likely to influence temperature and condensation … but we don’t know much about that other than there can be strong species specific relationships in some cases (e.g. isoprene emissions).
Hope the research goes well. These are super important topics. Let us know if you find out anything interesting!
Must be generally true for terrestrial hydrological cycles. But oceans cover 71 percent of the planet. It must therefore be so that ocean rather than land use/ forest processes are the primary climate drivers. Here, I suspect the homeostatic equatorial cloud/precipitation processes (Lindzen, Eschenbach) are a major ‘missing’ piece to the oversensitive GCMs.
From the abstract of Loeb et al(2012), H/t to R I Ellison & curryja: ‘CERES data show that clouds have net radiative warming influence during La Nina conditions and a net cooling influence during El Nino, but the magnitude of the anomalies varies greatly from one ENSO event to another.’
============
kim
Interesting.
Sounds like clouds act as a “natural thermostat” (negative feedback) in both directions.
Max
Lots of ocean out there to be sure. But what is the effective averaged surface area of a gridded Km square of ocean surface when surface perturbations (waves, spray, foam, etc) are included? How quickly can drier air come into close contact with the ocean “surface” to allow more water to enter the atmosphere? I would guess this has been studied. But I do know the effective surface area of the foliage on an equivalent 1 Km square parcel in a New England or Michigan woodland is enormous- i get to do those calculations every fall when I need to rake leaves off << 1% of that Km square.
Not true. The warming effect of sunlight is magnified by altitude (because the average air temp is lower). Therefore, changes in transpiration at higher altitudes will (probably usually) result in larger changes to the troposphere than changes to evaporation at sea level.
But that doesn’t mean that biological processes aren’t involved in driving changes to evaporation. Tiny amounts of oil floating on water can substantially retard evaporation, and floating biomass can provide a “wick” effect that can enhance evaporation.
Hi Rud
I suspect that forests are of global importance just because they are such effective producers of water vapour (much more effective than oceans per unit area). But agree that the oceans matter a lot too.
There are certainly interesting developments in marine systems that also point to a very plausible climate biology link. Corals (both the polyp animal and the algal symbionts) and many other marine organisms produce large amounts of DMSOs when stressed, and this plays a big role in nucleation and thus impacts cloud cover. I dont think that is well enough understood yet to model it, but it certainly looks a very plausible effect. With all the coral loss (etc) there are implications for downwind cloud and rain.
Algae in marine ice can also release a lot of volatile chemicals when the ice melts … that is also something potentially significant and leading to complex effects in polar regions.
Lots to be done to assess the magnitude of any such effects. Still early days.
Something to consider is when DMSO’s are released. IIRC they tend to be oxidized quickly to sulfer oxides when exposed to sunlight. If released during the night, however, and perhaps at under conditions of heavy cloud cover, they would probably travel considerably farther from their origin than in daylight. Farther vertically, and perhaps horizontally. Thus, it’s quite plausible (IMO) that even when the same amount is being released, the timing could determine whether they contribute to very low cloud cover, or higher (and possibly more diffuse) cloudy air. With potentially very different effects.
And it’s quite plausible that behavioral differences in established species could include changes to that timing.
@Steven Mosher…
Unicorns? Not really. We have very good scientific reasons to believe unicorns don’t exist. But no reason at all to suppose that effects such as these don’t exist. And if they do, very good reasons (based, of course, on mathematical models) to expect that they would contribute to complex and unexpected behavior of the climate/eco-system as a whole.
Biological feedback has been almost criminally neglected in the whole climate caper. And yet, there lies a huge carbon sink, and untold zillions of organisms, not one of them acting exactly the same.
===========
AK
thanks for the interest.
With the coral work the tides can play a crucial role (how exposed a tidal reef is) as does the temperature (high temperature means high stress and more emissions). This should allow us to evaluate downstream cloud after low tides and hot days … I dont think it has been done yet.
From above:
This is only a little different from what Dr. Trenberth said in 2009, as follows:
I don’t see much difference here except that Dr. Trenberth admits that he sees “natural climatic variability” or “natural variation” as proof of human-induced climate change.
Oceans are exempt from land use bias.
Earth is the water planet,
all its great continents awash with seas.
we know that the whole ocean is warming and sea level is rising at unprecedented rates.
we know that the whole ocean has warmed and sea level did rise, but the unprecedented rates is totally untrue.
The Roman Warming and the Medieval Warming did really happen. You may not be old enough to remember, but you are old enough to have read some history. What are you Alarmists thinking.
Whatever caused warming before IS causing the current warming.
Natural Variability DID NOT STOP.
NATURAL VARIABILITY DID NOT STOP AND GET REPLACED WITH CO2 WARMING.
THAT IS REALLY STUPID!
I TAKE BACK THE STUPID.
IT IS TRUE, BUT MY FRIENDS AND FAMILY AND PEOPLE ON THE OTHER SIDE, TELL ME TO STOP SAYING THAT.
So what you’re saying is evidence of natural variation should not be considered proof of human-induced climate change?
“IT IS TRUE, BUT MY FRIENDS AND FAMILY AND PEOPLE ON THE OTHER SIDE, TELL ME TO STOP SAYING THAT.”
HAP, maybe it’s time to start listening to your friends and family.
“sea level is rising at unprecedented rates.” Really? 13,000 years ago the ocean level was 130 meters lower than today. That is 1 meter in 100 years on average. I hope Dr. Trenberth’s other claims are equally unprecedented.
The system as a whole has cooled through the Holocene, while icecaps still melt. A friggin’ marvel, though too easy to explain to call it a miracle.
================
Hi Wagathon
Our comments are offered as speculation. We have a lot still to learn about these things. At this point we can be fairly certain there are a range of influences from land cover on climate, but we are only in the early days of understanding these links and their likely magnitudes. I expect there will be surprises!
Is there no longer such a thing as natural variation? As we see with global warming alarmism, Western academics have come to view every natural catastrophe as being caused by humanity.
Certainly … there will always be natural variation in these big complex systems. Problem is to distinguish it from the complex stuff that we could understand if we invested sufficient effort. For researchers calling something “noise” or “error” or “natural variation” is seldom as satisfying as getting a handle on the processes that explain it (though grasping its statistical behavior is better than nothing).
On my next blog about, ‘Climate Change Magic and Superstition’ and ‘Blood Moon Global
Warming and Astrology,’ I probably will have something a little more down to earth to say about it –e.g.,
Obviously, it is in the interest of the global warming lobby – i.e., the teachers of human-induced climate change in our schools – to adopt a view that nothing can be seen as excluding the possibility that late 20th century warming was caused by increases in anthropogenic-CO2 increases in the atmosphere (the AGW theory).
I take your point but it is not entirely fair to researchers. Most researchers are particularly interested in what we don’t know — if we knew everything we wouldn’t need research. So for us the uncertainties are important (and fun too). Its what we work on and what motivates us. The big uncertainties will always get a lot of emphasis.
The True Believers demonstrate fear, not awe; irrational ignorance, not reasoning power. They urge helpless and hopeless impotence, not boldness; and, that’s a pity. The greatest terror for them is to be awake when truth happens, these schoolteachers of AGW catastrophe.
@ Douglas in Norway
“Our comments are offered as speculation. We have a lot still to learn about these things. At this point we can be fairly certain there are a range of influences from land cover on climate, but we are only in the early days of understanding these links and their likely magnitudes. I expect there will be surprises!”
Clearly you never got the memo: “The science is settled; it’s Anthropogenic CO2 all the way down.”
This would indicate that at some level, you have to give water up (to the atmosphere) to get water back, which makes me wonder what effects California water-conservation measures (cutting back on irrigation) have on worsening the droughts there.
On some level what inspires fears of human-induced climate change is a large measure of irrationality–e.g., dig fossil fuels out of the ground and turn it into the energy needed to turn salt water into fresh and make deserts flower with it. It sounds possible but, does it sound inspirational, aspirational or an unmitigated evil that neither man nor woman should ever do?
Water you give up with evaporation goes thataway and the water you get from precipitation comes from theotherway.
More CO2 does allow the green things to grow better while they use less water.
I’m missing a word both in the article and the blog (and comments) here: “convection”. Mind that evaporation brings more gas (water vapor) into the atmosphere, with a lower specific mass than air (18 vs 29 gram/mole). Therefore the wetter air has to expand, reduces in weight and gets more buouyant. Hence one may expect more convection above the evaporating forests than elsewhere, forming cumulus type of clouds. And that’s only the beginning of a lot more dry and wet adiabatic processes.
Yes, not only convection is missing, but also latent heating, a process that also leads to low pressure and convergence of winds in the more traditional and well known feedback between deep convection and the surface pressure. I don’t see why we need another mechanism for something that is already explained.
Convection and latent heat aren’t missing from the articles. They’re not mentioned by name in this blog entry, but they are clearly assumed, and convection is depicted in the figures.
…also, the enhanced feedback provided by the “biotic pump” mechanism doesn’t provide an alternate explanation to known convective phenomena but rather a further refinement to explain regional variations in rainfall and circulation patterns.
Hi Leftturn et al.
Yes fair points. I try to keep the jargon limited to keep the blog clear and simple for a broad readership. A blog has to be brief and focused and I think this was already a bit scattered.
We have addressed many of the alternative ideas in other more technical texts (see, e.g. http://arxiv.org/abs/1404.1011). let me know if you have trouble finding what you want.
Jim D says “I don’t see why we need another mechanism for something that is already explained.”
As a research scientist I would hope we can select find the explanation that works best. Ancient astronomers were well able to predict the locations of the planets before the heliocentric theories were accepted.
I also think that we make everything fit the “accepted explanations” when we lack alternatives.
When you dig you may be surprised (as I often am) that many foundations are less sound, and more open to question, than you might think: see, e.g. http://arxiv.org/abs/1308.6301.
The article notes that “despite major investments in incorporating land cover in climate simulation models, much remains uncertain,
Wait, What, 97% for sure still allows much to remain uncertain. Tell that to the IPCC and the mainstream Media.
Nice to see a thread that does not mention CO2, or at least assumes implicitly a constant level. Surely climate science would benefit enormously from a 10-year pause on studying anything to do with changing CO2 levels.
shorter mikky: “burn the books, burn the books”
Still, the current CO2 deficiency although not worrisome is at odds with the geophysical history of the Earth.
So despite the global “greening” some would like to attribute to more CO2 the actual byproduct of all this plant growth ie. oxygen, has been trending downward in a mirror image of the CO2 rise.
http://scrippso2.ucsd.edu/
… or, are O2 levels rising?
http://t0.gstatic.com/images?q=tbn:ANd9GcQeaDfk5Mqe-QXjRu-wiv-FfGUPjZZqO3jOZ4_tiTmFW9VuT-qZzA
Put another way, the global greening is a result of the warming, which logically should also cause a CO2 rise from ocean release due to ‘simple physics’. This is a phrase often used for the greenhouse effect but casually ignored by the same people when they want to introduce unphysical concepts like deep-ocean warming or a warming ocean being a carbon sink.
The idea that a CO2 rise must be due to man originaly arose form an inability to balance the carbon budget which in turn arose from ignorance about natural carbon sinks to take our extra 2% – despite the knowledge that there must be ‘missing’ sinks and that demonstrable global greening demonstrates some of them in action. To back up the unphysical ocean sink idea some hokey calculations were done with massive error bars which argue that the unphysical is somehow true.
Basic research though uncovers many published papers (some of which I have previously linked to on this blog) which found these ‘missing’ terrestrial carbon sinks by the simple act of actually bothering to look for them. The sum total of these ‘found’ sinks are more than enough to explain both the ‘missing sink’ plus the extra sink required to cater for CO2 release from the ocean – which of course simply agrees with what we would expect from the physics.
Of course, arguing for a natural increase in CO2 is something that few people, even skeptics, want to contemplate but it remains what the physics tell us should happen. The reason it is so casually dismissed is because there is an inbuilt gut feeling among earth scientists that man must be destroying the planet because – well we must be. Hence prior to global warming we had global cooling from those selfsame fossil fuels: A hypothesis that disappeared simply because nature changed it’s mind and started warming again. And we then had the exaggerated acid rain scare also from fossil fuels.
One thing this pause has shown very clearly is that if basic observations can be summarily dismissed by consensus scientists in favour of obviously inadequate models then it is abundantly clear that they prefer only to recognise the data (as well as the physics) that supports alarm – and hence more funding. What is sauce for the goose is sauce for the gander so skeptics should feel free to do the same. Of course the idea that the Earth cannot absorb an extra 2% from man is quite ludicrous at first glance. If Arhennius had known this fact he’d not have bothered.
~Vincent Gray
An increase in atmospheric carbon dioxide (CO2) concentration influences climate both directly through its radiative effect (i.e., trapping
longwave radiation) and indirectly through its physiological effect (i.e., reducing transpiration of land plants). Here we compare the climate response to radiative and physiological effects of increased CO2 using the National Center for Atmospheric Research (NCAR) coupled Community Land and Community Atmosphere Model. In response to a doubling of CO2, the radiative effect of CO2 causes mean surface air temperature over land to increase by 2.86 +/- 0.02 K (1 standard error), whereas the physiological effects of CO2 on land plants alone causes air temperature over land to increase by 0.42 +/- 0.02 K. Combined, these two effects cause a land surface warming of 3.33 +/- 0.03 K. The radiative effect of doubling CO2 increases global runoff by 5.2 +/- 0.6%, primarily by increasing precipitation over the continents. The physiological effect increases runoff by 8.4 +/- 0.6%, primarily by diminishing evapotranspiration from the continents. Combined, these two effects cause a 14.9 +/- 0.7% increase in runoff. Relative humidity remains roughly constant in response to CO2-radiative forcing, whereas relative humidity over land decreases in response to CO2-physiological forcing as a result of reduced plant transpiration. Our study points to an emerging consensus that the physiological effects of increasing atmospheric CO2 on land plants will increase global warming beyond that caused by the radiative effects of CO2. http://www.pnas.org/content/early/2010/04/30/0913000107.full.pdf+html
Most of the water in the hydrological cycle – some 90% – originates in the oceans. This is not to say that local and regional effects are not significant. Increased runoff has implications for aquatic and marine environments. Lower transpiration has implications for local rainfall and most especially dew and therefore the structure of terrestrial ecosystems. Not to mention the impact of lower evaporation on surface temperature. The loss of forest amplifies the effects on hydrological processes.
Water use in plants has been studied for a very long time – so I am failing to see how calling it a biotic pump adds much to understanding. Forest loss is moreover just one issue in a much broader problem.
“Water use in plants has been studied for a very long time – so I am failing to see how calling it a biotic pump adds much to understanding”
The pump concept is that the evaporation and condensation processes determine large scale atmospheric pressure gradients. The feedback involved in this concept (see second part of the blog above) imply that forests can draw (moist) wind from elsewhere. That’s the new bit.
Large scale pressure gradients are not exactly new.
e.g. http://www.oceanoasis.org/teachersguide/activity5.html
Only slightly tongue in cheek. Obviously forest transpires significantly more than grass or evaporation from bare dirt or even from open water surfaces – with effects on local and regional hydrology as well as surface temperature.
The other control on local and regional hydrology – which was the larger point – is the stomata control mechanism which seems to be relatively significant. CO2 reduces transpiration losses and so reduces the flux of moisture to the atmosphere. It is often said that lower plant water use is a good thing – but this seems less obvious in an ecosystem sense.
Nope. You don’t have any evidence that carbon dioxide warms the surface. In contrast I have evidence that the greenhouse gas water vapour cools, as you could read here.
Nor do you have any valid physics that could explain this, but I do.
Having lived in the tropics myself I know the stories that drought follows deforestation, and that a rainforest maintains humid conditions. I find it there fore strange that drought is modeled for the ITCZ in the Amazon (irrespective of deforestation) as there is ambient water available. Does anybody know the rationale behind this drought amazon model?
“drought is modeled for the ITCZ in the Amazon (irrespective of deforestation) as there is ambient water available. ”
Hi Hans — not sure I understand the question.
Many researchers have attempted to assess the contribution that forests make to rainfall in the Amazon interior. Contrasting the predictions of different theories and models is one way to distinguish among them.
The biotic pump approach implies that complete forest loss could lead to very little rainfall in the interior (i.e. 95% decline), while many (conventional) models suggest a much lower decline (around 30% decline). As models improve (to reflect the advances I detail above) even if they don’t adopt the biotic pump their predictions of rainfall decline with large scale forest loss are likely to increase (simply reflecting the larger contribution that forests make to atmospheric moisture).
Maybe take a look at this for more background:
http://lomaprieta.sierraclub.org/forest_protection/FeatureArticles/HowForestsAttractRain.pdf
I hope that helps.
“water vapour is a powerful ‘greenhouse gas’ and cloud cover influences planetary albedo (a measure of the solar radiation reflected into space).”
Yes. indeed.Although the term ‘greenhouse gas is’ is misleading and should be abandoned (there is no greenhouse in the sky), the analogy is useful here. At 15 microns some IR is absorbed by CO2, whereas at 20 microns, nearly all IR is absorbed by water vapour
However because no one looks critically at model development and there is no debate about it, we have no way of knowing whether these sort of considerations are included. Is it not time that we had a hard look at IPCC models?
@alexander Biggs Many universities and institutes have their own global climate models. The IPCC writers summarise information from them in the report. There are active projects comparing the global models with each other. There are also regional models which can work on smaller areas with higher time resolution and more detailed physics processes. Then there are weather forecasting models which work on short time scales. There are active projects looking at case studies (regional, vegetation, moutains. cloud properties), results of which are used to improve the parametrization schemes of the models.
Predictions from global climate models, unlike weather forecasting models, can not be verified the following week. There is an element of trust that is required to believe the predictions made by global climate models 50 years into the future. I do not have this trust because of the uncertainties due to vegetation changes and clouds. That’s the reason I find this topic so interesting and worthy of discussion.
““water vapour is a powerful ‘greenhouse gas’”
So it should warm the surface by about 25 degrees. Maybe just 10 degrees in a dry desert, but definitely 30 degrees or more in a rainforest. /sarc
But it doesn’t, as you can read in a study which presents data showing that it cools, and an explanation here of the physics which explains why.
The reforestation of the Northern Hemisphere started to occur after the invention of the steam engine and introduction of coal.
Good point:
~Starre Vartan, mnn
Indeed the largest wood pulp producer in Sweden “Stora” is named after the copper mine in Falun, Growing trees was in the end more profitable than digging copper.
“..it is worth noting that the vaporization of water consumes nearly half the solar energy reaching the Earth’s land surface ”
Douglas, how is that actually defined (noting the use of the term “energy” not “sunshine”) and measured? And what is the corresponding figure for the oceans, if available? Thanks.
Hi Michael Hart
All these figures are global estimates rather than precise measurements.
In Jasechko, S. et al. (2013) Terrestrial water fluxes dominated by
transpiration. Nature 496, 347–350.
(this should be public? … see, http://www.science.uwaterloo.ca/~jjgibson/mypdfs/nature11983.pdf
and you can find:
“Volumetrically, transpiration converts 62,000 km3 /yr of liquid water into atmospheric vapour, requiring 33 W/m2 of latent heat, or roughly half of all solar energy absorbed by the continents (approximately 70W/m2)”.
I’ll search for ocean figures but I think you could estimate it directly from annual evaporation from oceans, ocean area and latent heat.
Perhaps it is here:
http://echorock.cgd.ucar.edu/cas/Staff/Fasullo/my_pubs/Trenberth2009etalBAMS.pdf
it has a good summary of the different components and measures in any case.
Evaporation of water does not consume any energy.
The combination of evaporation and later condensation is the strongest form of heat transfer from oceans. It’s important also in land areas, but not as large as over oceans.
Hi
You might find this (old) summary of interest.
http://eas8803.eas.gatech.edu/Reading_Materials/ShuklaMintz82.pdf
It suggests that if we could somehow stop landsurface derived evapotranspiration ( i.e. no energy now goes to vaporise water “enthalpy”), some land temperatures would rise by 15-25 degrees C.
Of course many of the assumptions seem questionable (I dont believe water vapour dynamics were completely understood or thus appropriately simulated, so I don’t quote it in the main article), and the models are now much more sophisticated, but the rough magnitudes from the study remain striking.
Thanks for the reply Douglas.
I just happened to see a show about the Redwood forest a couple of days ago. Apparently, one of them can suck thousands of pounds of water from fog.
From an article on them:
…
Because the California summers are dry and have no rain, the moisture from the summer fog is in high demand and trees can use up to 600 liters/day (Dawson 1998). Redwood foliage is actually very efficient at “stripping” fog moisture from the air and making it available for the ecosystem (Dawson 1998). Dawson (1998) also notes that during the summer months, redwoods may get up to 40% of their water from fog, and that fog can account for 13-45% of its water uptake annually.
…
http://online.sfsu.edu/bholzman/courses/Fall99Projects/redwood.htm
From another article:
…
Redwoods are a hydrostatic marvel. They can siphon water upward to great heights, fighting gravity and friction every inch of the way. And during the dry summers in California, the coast redwoods actually create their own “rain” by condensing heavy fog into drenching showers that provide welcome moisture to the roots below.
In addition, scientists believe that redwoods take in much of their water directly from the air, through their needles and through canopy roots which the trees sprout on their branches. Lofty “soil mats” formed by trapped dust, needles, seeds and other materials act like sponges to capture the water that nurtures these canopy roots. Moisture from fog is thought to provide 30% to 40% of a redwood’s water supply.
…
http://www.datreestore.com/coresese.html
So, they not only transpire, they also can “drink” fog through the leaves and canopy roots. It seems this would affect water vapor availability in the region.
Jim 2
Yes indeed. Many trees, especially in cloud forests, and in coastal fog regions, are very effective at what is sometimes called “cloud stripping” that is gathering water droplets out of the air. Often pendulous mosses and lichens help. If the water drips from the canopy it can provide moisture to plants below (can cause very local moisture effects in areas with reduced tree cover). This cloud stripping effect contributes significantly to catchment values in some parts of the world but remains poorly quantified in general. Note that any water intercepted that is not lost to rivers and the like can be evaporated back to the atmosphere and so remains in play. This may/can help the overall feedback by drawing in more wet winds via the biotic pump (as laid out above, by helping reach the critical humidity).
I just finished reading a book about mosses (Gathering Moss). They also hold a great deal of water. They are being harvested relentlessly for garden centers, in particular, those in Oregon.
This should be rather easy to test out, experimentally.
Make a large number of solar panels on poles, use them to charge batteries during the daylight hours.
Have the batteries cool the underside of the panels, just before dawn, using peltiers.
Plant a load of them in New Mexico or West Texas and see if you change the soil hydrology and rainfall.
So which problem is worse deforestation or rising CO2?
WOW, finally they are realizing that: rain-cloud avoids deserts and prefers where is forest and lots of topsoil moisture… what a ”science” (they ”discovered” what even the Stone-age people did know… : http://globalwarmingdenier.wordpress.com/water-vapor-h2o/
Hi Stefan
Indeed I started my first joint article on the biotic pump by saying more or less the same thing. “Local people in many partially forested regions believe that forests “attract” rain, whereas most modern climate experts would disagree. But a new hypothesis suggests that local people may be correct.”
see http://lomaprieta.sierraclub.org/forest_protection/FeatureArticles/HowForestsAttractRain.pdf
The real question is which is the cause and which the consequence. If we put forests in the Sahara would they water themselves?
Hamlet:
And therefore as a stranger give it welcome.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.
Hamlet Act 1, scene 5, 159–167
The local newspaper (Ft.Collins, CO) today carried a ‘Soapbox’ (super letter to the editor) from a local college prof after his visit to Australia. the Australians convinced him that plant biology is changing because of the extra co2. Among other things leaf size is tending to increase causing more water evaporation and resulting in drought or death of the plant (read “forest”) if it cannot adapt. He also stated that increased sea levels have submerged small islands in the Pacific.
I am a physicist, not a plant biologist, so I will let others debate the leaf size problem. However, have any islands actually submerged due to rising oceans except perhaps. for small sandbars during typhoons?
Sea levels rose about 22.5cm since 1870. I am unsure if any island has that much elevation, or less, back then. It would now be submerged just on account of that (though there are other factors such as erosion or subsidience). In recent years the average rate of sea level rise was lower (1.2mm/year) than the global average (3.2mm/year) in Polynesia where the Tulavu islands are especially at risk. But this can’t be expected to last since even though ocean and atmospheric circulation patterns modulate gradients, those gradients remain bounded by gravitational forces. The longer the period, the least the relative difference will be between the cumulative sea level increase at different points around the globe.
From memory most of the small Pacific islands are coral based, they rise and fall in line with changes in sea level. I recall reading articles which show that Tuvalu’s land area has increased during the post-1970 period. So such islands would not be submerged by rising oceans. Another furphy.
The Land:The flat islands seldom rise higher than 15 feet above sea level. Five of the islands, Funafuti, Nukufetau, Nukulaelae, Nui, and Nanumea are atolls – large, roughly circular columns of coral which rise up almost vertically from the sea bed, forming a reef, with coral islands occurring where the coral rises above high tide level. Large lagoons are enclosed within the coral reef. Many “artificial” lagoons are on the various islets of Funafuti, as the results of extracting material for the runway built by American forces during World war II. The remaining four islands are pinnacles of land rising up solid from the sea bed. Some have salt-water ponds on them, while Nanumea has a fresh-water pond, a rarity for atolls. Coconut palms cover most of the land.
http://www.tuvaluislands.com/about.htm
The value for Land area (sq. km) in Tuvalu was 30.00 as of 2011. As the graph below shows, over the past 50 years this indicator reached a maximum value of 30.00 in 2011 and a minimum value of 30.00 in 1961. [So changes have been minimal, but there has been some increase from 1961 to 2011.]
http://www.indexmundi.com/facts/tuvalu/land-area
This constant rounded up 30.00 km^2 figure (at variance with other estimates around 26 or 27 km^2) seems like a conventional figure rather than a annually conducted topographical survey.
Informative essay on Floating Islands (and parrot Fish) by
Willis Eschenbach.
http://wattsupwiththat.com/2010/01/27/floating-islands/
The silent partner in this whole sea level rise issue is subsidence. It only gets a passing thought, however in some regions the vertical drop in shoreline is significant. The Chesapeake Bay region is suffering from subsidence mostly due to groundwater abstraction and the estimate is that over half of the sea level rise to due to just that factor.
“I am a physicist, not a plant biologist, so I will let others debate the leaf size problem”
Plants are biological entities and so have evolved with one aim, producing viable offspring. One of the major problems plants have is the inefficiency of fixing carbon, the lower the concentration of carbon the more energy plants have to use to fix it. Increasing CO2 levels makes its easier for plants to fix CO2, so they become more efficient.
What they do with the savings in their energy budget is unknown; they can invest in self, in the case of trees increasing their rate of growth so they can capture more light next year, or invest in more fruiting bodies. The most likely thing to do is invest in both.
Making leaves is an investment, the bigger you make the leaf, the bigger the cost. Bigger leaves can harvest more sunlight, so initially, more bigger leaves = more sunshine captured. However, the leaves are all in the same local, the tree, and so new leaves can intercept light that would be captured by existing leaves. The trees need to perform a cost benefit analysis on investment in leaf area and intercepted photons. If rising CO2 means that trees are growing bigger leaves, then they appear to have a energy budget for leaves and so a bigger energy budget means bigger leaves.
Bigger leaves, smaller soma, same sort of water usage for the tree, but more carbon fixed, and eventually, more carbon mineralized.
Plants invest in more than growth and/or fruiting bodies. False dichotomy. They invest in toxins to kill stuff that tries to eat them. Then invest in sugars to get stuff to want to eat them and spread their undigestible seed in the process. They invest in protective coverings. They invest in food to see them through the winter. Lots of different investment strategies. They say evolution is smarter than you are. I believe it.
David that was uncalled for, I was giving an overview of the major responses that species like trees have to changing conditions; self or seeds.
In trees, a major investment in self comes with growth, as large trees can capture more sunlight and dispense more seeds than small ones.
“So such islands would not be submerged by rising oceans. Another furphy.”
If the rate of sea level rise increases, as it is expected to, they might.
This article at arXiv, noted in your introduction, seems to dwell on an issue that has been long-settled in most of the two-phase flow literature. I found it interesting that you have employed the exact same ‘train and rocks’ analogy that me and some co-workers have seen invoked. And the Red and Green water is exactly the same as of us, too. Even the colors :-)
I suggest that a literature search and review will show that yet another peer-reviewed paper on the issue is not warranted. And, yes, there are papers that don’t have some details correct, no matter what the subject, but why go over these yet again.
A major interest in approaching modeling of the con-current flow of compressible vapor and liquid phases of boiling/two-phase water that started in the mid-1970s has led to publication of literally hundreds of papers and reports and proceedings and presentations that focus on derivation of the fundamental equations; maybe even thousands. The publications continue to this day as a well-crafted Google will show. Thousands more publications are associated with development of the engineering models and empirical correlations that are required to close the equation systems. This review paper from 1983, A. Bedford, D.S. Drumheller, Theories of immiscible and structured mixtures, Int. J. Eng. Sci. 21 (1983) 863-960, cites, I think, over 268 references, more or less. That paper was written 31 years ago and after only about 10 years of focus in the engineering literature.
The continuum mechanics investigations generally started before deep engineering investigations, starting in the, say, mid-1960s. It is very interesting to me that the continuum mechanics approach required several years, many investigations, and several very prominent mechanics including Green, Naghdi, Atkin, Bowen, Eringen, Mindlin, Rajagopal, and Truesdell. From time to time pure mathematicians dabble in the arena ( the distinction between pure mathematicians and pure mechanics is vanishingly slight, in my opinion ). It’s a wonder that we mere engineers could even think that we could make any contributions. But we have real problems to solve and we have made contributions and solved real problems.
The notation of “two-phase flow models” for water in which liquid and vapor phases were of interest was initially expanded to “two-fluid models” and later to multi-fluid models and more recently to multi-fluid, multi-physics, multi-scale thermal sciences :-)
There seems to be two favored approaches to derivation of the model equations; (1) continuum mechanics, which is a truly first-principles approach, and (2) spatial averaging of the local-instantaneous form of the Navier-Stokes equations to arrive at balance equations for each phase or fluid or region in the flow field. The existence of interfaces between the phases/fluids/regions leads to introduction of the mass, momentum, and energy jump conditions across the interfaces in both approaches. Delineation of the regions of space occupied by each phase or fluid and the associated boundaries of those regions leads to the need to describe the mass, momentum, and energy interactions and interchanges at those interfaces.
The reaction force discussed in the arXiv paper is, I think, considered to be among the less important forces in the case of almost all engineering flow applications. Additionally, there is an important application issue associated with the force that can be illustrated as follows. Consider a liquid droplet at the local saturation temperature and flowing parallel to a stationary surface that is at a high temperature such that only a portion of the surface of the droplet faces the high temperature surface. The reaction force due to evaporation of the droplet will be occurring only on the portion of the droplet that faces the high temperature surface and that reaction force will act so as to move the droplet perpendicular to the surface.
I think it would be a rare practical application in which the effects of spatial and thermal relationships on the distribution of the evaporation can be sufficiently defined so that the components of the reaction forces could be determined and incorporated into the momentum balance equations. Assigning components of the macroscopic velocity to the reaction force is not correct.
Accounting for the mass exchange and associated energy exchange in the mass and energy balance equations, on the other hand, is important.
Thanks Dan
Will give that a look.
Your point is well taken. Indeed we acknowledge in the article that the correct equations are known and published (originality is not our claim).
The reason we do this is that these basic physical behaviors are crucial in the biotic pump model. The wrong expressions are widely used and widely cited. That is surely a problem and makes the discussion difficult.
see e.g. the discussion at ACPD
http://www.atmos-chem-phys-discuss.net/10/24015/2010/acpd-10-24015-2010.html
especially:
http://www.atmos-chem-phys-discuss.net/10/C12008/2011/acpd-10-C12008-2011.pdf
If we don’t agree the correct expressions, or care enough about them to get them right, we are not able to agree on the implications. For us, its about taking an argument from A to Z and finding that you disagree with 90% of your audience where B and C come.
Many believe that sophisticated climate models are sound. Our paper shows that they are unsound and the most basic behaviors of water are not correctly represented. If we can agree on that, it is a useful step.
Hope that was clear enough (not just a rant). Thanks again for the input I think we agree on this.
Good post. thank you very much.
Leaf area index can be as large in forests as 10, although it is usually somewhere around 5. Then comes the internal structure of leaves with a layer of spongy mesophyll cells at the back side. Its internal surface is about 30 times that of leaf surface. Therefore area of air-water interface in forests is at least 2 orders of magnitude higher than area of forest itself, provided stomata are wide open.
Rate of evaporation is proportional to this area.
Please note effective interface area is regulated by trees themselves and it is independent of wind speed.
Over ocean interface area can only be boosted by sea spray, but very high wind speeds are needed for a 2 orders of magnitude improvement.
Hi Berényi Péter
Great contribution — much appreciated thanks. It is too easy to underestimate what the forests actually do as so much is hard to visualize.
Tropical forests evaporate over a meter of water equivalent per year, some manage more than two meters.
@Douglas in Norway
Forests also make their own cloud condensation nuclei. That’s necessary, because equilibrium vapor pressure over a liquid increases fast with decreasing droplet size. That means clean droplets below a certain size just get evaporated. But how would one have large droplets if small ones are not allowed to grow?
The starting points are tiny dust particle (various sources). These grow by accumulating (sticky) material that often appears to involve partially photo-oxidised organic compounds. Once they are large enough (and have the right kind of surface properties) they become effective at accumulating moisture. I know from previous searches that there are many good online resources about this … here is a paper I like
http://web.mit.edu/qichen/www/pdf/Poehlker_Science2012.pdf
And a useful summary of more detailed links.
http://pierce.atmos.colostate.edu/publications.htm
No coriolis? Winds don’t run down pressure gradients except very near the ground, or in the tropics.
Certainly there is a long list of factors that have an effect. Coriolis effects, terrain effects … also atmospheric dust, ocean temperatures. It all depends on the phenomenon of interest.
Here I wanted to focus on specific terrestrial biology links.
Anastassia and the team have done a lot of work on cyclonic systems in which coriolis is key. See, e.g. http://www.bioticregulation.ru/ab.php?id=pla11 (section 3 I think)
Faustino: One of the fore sights of the Menzies Australian government in 1939-1940 was to order 2 squadrons of Catalina (PBY) flying boats. At that time few Pacific islands had landing strips, but all had lagoons. As a wireless/air gunner on Catalina s I visited many atolls. In 1942 we were able to rescue the crew of a USAFB26from an atoll in the solomon islands group. At that time the Solomon Sea was rapidly becoming a Japanese lake an the B26 was damaged in a raid on Rabaul in PMg which had recently fallen to the Japanese. They had made it to this atoll where we could land and pick them up..
Appears younger than his stated age.
=============
Alexander Biggs,
Have u published a diary or memoirs?
Beth the serf.
BREAKING CLIMATE-CHANGE NEWS
“DEVASTATING EPIDEMIC” OF HEAT-CORRELATED KIDNEY FAILURE
IN COASTAL CENTRAL AMERICAN STATES
Bacteria, and insects, and *some* trees do exceedingly well in ever-hotter, ever-more-humid climates. Human beings, not so much.
The Chief’s team of world-class scientists will no doubt be looking into this emerging class of third-world climate-change disaster.
Libertarians, not so much, eh Climate Etc readers?
They bleed a lot, you know.
============
I might say you’re on to something there Fan except that it hasn’t, you know, actually warmed in nearly 20 years.
Unsupported claim by pokerguy, central American data by FOMD.
Your exhibition of willfully ignorant denialist cognition is instructive to Climate Etc readers, pokerguy!
Lesson? Keep hydrated! Common Sense solutions from the rafter.
“pokerguy” “denialist cognition.”
Come on, Fan, you can do better than that, can’t you? Even your pal Hansen concedes there’s been no warming in at least ten years.
Fan
Your post at 10.20
Forgive me, but what has your South American link got to do with warming?
Ps. The Met Office believes there has been a pause. I have referenced you at least 3 of their studies on the subject and I was at their office in December talking about it.
tonyb
Fan
or even Central America
tonyb
“Forgive me (Fan) but what has your South American link got to do with warming?”
Yes Tony, doesn’t say a thing about global warming, or even localized warming, that I could see anyway. That’s Fan doing her impersonation of a jazz musician…which is to say making it up as he goes along. As to the Met Office and their current embrace of the pause, or Hansen’s, or TRenberth’s, or anyone else’s on her tea…, or how many studies you show him… it simply doesn’t matter.
Of course the funny thing is that *we’re* the “denialists.”
Projection much?
What heat-color was Mesoamerica? What does chronic heat-stress do to kidney function?
Conclusion I Kidney’s face plenty of challenges; increasing heat and humidity can initiate chronic renal failure, with devastating/fatal consequences.
Conclusion II Denialists are comparably adept at foolishly insisting upon wrong questions, as ignorantly embracing wrong answers and/or willfully ignoring inconvenient data.
That’s obvious to everyone, eh Climate Etc readers?
Fan
So you post Central America February figures, make an obscure reference to kidney failure and totally fail to mention the cold weather in the US? If I posted short term figures for one area and then related it to an obscure abstract in order to ‘prove’ something, what would be your reaction.
This was not your finest hour and please post articles we can read, not abstracts.
At least when you post Hansen’s material (this is not an invitation) generally it is open access.
tonyb
Well it is conclusive, FOMD is as good at nephrology as he is at chemistry, maths, physics and logic.
He will soon produce references showing that the people who historically did hard physical work in high temperature environments, like puddling furnace men, stokers and members of the USMC during the Pacific campaign all suffered from kidney failure.
The link says it all.
http://www.breitbart.com/Big-Government/2014/04/15/EPA-Says-U-S-Greenhouse-Gasses-Fell-By-10-Percent-Between-2005-and-2012
manacker | April 16, 2014 at 3:52 pm |
David Springer: I looked for an experiment confirming that air temperature rises in higher CO2 environment with no change in illumination and found nothing
And you won’t, because there is nothing that is based on empirical evidence in our atmosphere.
The Reverend and Mosh can bluster all they want to, but they cannot cite such a physical observation or actual reproducible experiment.
—————————————————————————-
Yep. I’ve been asking for years. Bill Nye the Science Guy and Mythbusters is as good as it gets.
You’d think something as fundamental to the [luke]warmist narrative would be measured in a lab to hell and back with 9 significant digits to the right of the decimal point. But noooooooooooo… Bill Nye the Science Guy using pop bottles is state of the art. Vaugn Pratt the Stanford computer scientist gave it a whirl with cardboard boxes and Saran Wrap on his front porch and did worse than the Mythbusters. It’s pretty pathetic. Now the whole house of cards is collapsing as the unpredicted pause is killing the cause.
The CO2 heated hot air in global warming appears to be metaphorical in nature.
LOL
Ahhh … David Springer, as you say “but they cannot cite such a physical observation” but we can now cite a study that the greenhouse gas water vapour (the worst of these “pollutants” by far) does cool like this, and we can explain the physics as to why this puts a spanner in the works here. Fascinating reading I assure you.
Yeah Doug the water cycle has a net cooling effect. Right on, man.
No Doug gravity doesn’t make the bottom of an atmospheric warmer than it would be without gravity. It makes the top of column the cooler. The mechanism by which this happens is gravitational potential energy at the bottom of the column is zero while at the top of the column gravitational potential energy is non-zero. Sensible heat at the bottom of the column is converted to insensible gravitational potential energy at the top of the columnn.
In a non-convecting atmosphere of course which doesn’t actually exist in nature.
It’s not complicated and no matter how much you try to make it complicated it just isn’t.
You write nonsense David Springer. My response is in my book and a lengthy comment awaiting moderation.
There is no net gain in gravitational potential energy at the top of the troposphere, David Springer. There’s been roughly the same density of air molecules up there for yonks. But you seem to want to see an energy transfer from the surface to the top day in and day out. I’m sure silent readers will see the ridiculous nature of your guesswork.
The existence of the gravito-thermal effect is proven both from standard physics (such as in my book) and empirically in the Ranque-Hilsch vortex tube. That is the end of the matter, David Springer. And that is the end of the greenhoax.
Mosher says all you need to know about me is I’m an ex game programmer. Not really true it was more a hobby than a profession but I like the style of his put down.
All you really need to know about Mosher is he’s an English major who can’t spell the word “warrant”.
ROFL
The Biotic Pump hypothesis can be boiled down to:
Trees are better at moving soil moisture into the atmosphere than sand thereby creating a low pressure system over the trees that pulls in warm moist air from the adjacent ocean while pushing out cold water in rivers through the magic of gravity.
I’m shocked. Who knew that’s how the water cycle works?
Oh wait. I need to rephrase.
I’m shocked. This is common knowledge. Who doesn’t know that’s how the water cycle works?
If you go back and read the previous blog on condensation driven winds (linked near the start above) it will help you to clarify what is and is not considered controversial.
What did the authors get wrong?
Diluting a gravitationally confined column of gas with a lighter gas always results in less mass in the column if temperature is held constant.
I wrote at the very beginning that what Willis missing is a change in temperature associated with evaporation. Evaporation moves sensible heat into latent of heat vaporization. This cools the air. Colder air is denser. This creates a higher pressure until condensation occurs which reheats the air it becomes less dense and pressure falls.
It’s the change in temperature Willis missed. He was absolutely 100% correct that more water vapor at constant temperature lowers pressure.
This is obviously way the phuck over your pay grade.
David Springer explained:
“What did the authors get wrong?
Diluting a gravitationally confined column of gas with a lighter gas always results in less mass in the column if temperature is held constant.”
I see! Mixing some amount of a light gas with a heavier gas can reduce the total mass of the gas. Some of the individual molecules probably are losing mass in the process. Lavoisier must have overlooked that possibility. Thank you!
“I wrote at the very beginning that what Willis missing is a change in temperature associated with evaporation. Evaporation moves sensible heat into latent of heat vaporization. This cools the air. Colder air is denser. This creates a higher pressure until condensation occurs which reheats the air it becomes less dense and pressure falls.”
Yes, I got it now! The weight of the total air column changes! That must be for the same reason why one pound of lead is so much heavier than one pound of feathers! Thank you!
“This is obviously way the phuck over your pay grade.”
Yes. I hadn’t realized how far behind I was. Thanks for the enlightenment. I feel like I am now a better amateur scientist.
“Diluting a gravitationally confined column of gas with a lighter gas always results in less mass in the column if temperature is held constant”
Right, if the temperature AND pressure are held constant that is correct … but we are still interested in pressure not weight. They are not the same and the difference matters.
A tethered balloon filled with helium is lighter than the surrounding air, but it doesn’t collapse (but fills the balloon in balance with external pressure + the tension of the balloon, so in fact is at slightly higher than external pressure). Sitting under this balloon, even if it is very very big, will not lead to local reduction in air pressure (in the same way that sitting under a plane does not crush you).
Helium is lighter than air, but releasing helium rapidly from a compressed gas tank (lets agree temperature is constant to keep it simple) will still cause local pressure to rise simply because there are more molecules in play (consider doing it in a small room). In fact if everything else on the planet was help constant (a thought experiment, I dont imply that we can do this) and you open a cylinder of helium, and wait for global equilibrium, mean atmospheric pressure will rise and balance the additional weight in the atmosphere (so pressure and weight are related at the largest, but not the local, scales).
Consider a big forest 2000 km across. The forest adds vapour equivalent to a few mm of water every day. This several mm of vapour is additional to the atmosphere already there … so it causes an increase in pressure.
I hope that helps.
Douglas in Norway “Sitting under this balloon, even if it is very very big, will not lead to local reduction in air pressure (in the same way that sitting under a plane does not crush you).”
This is very helpful, thank you! I had wrongly assumed that the weight of the total column above was the sole determinant of the local pressure at the bottom of the column (neglecting transient pressure waves and lateral material fluxes). I now realized this is untrue. The balloon case isn’t entirely analogous to the airplane case, though, since the airplane, unlike the balloon, communicates downward momentum to the air that flows around its wings, and air carries this momentum to the ground, thus resulting in a transiently higher pressure over a wide area. The buoyant balloon produces no similar effect on the ground, not even transiently.
“…and air carries this momentum to the ground, thus resulting in a transiently higher pressure over a wide area.” …and it’s just because of this spread that you aren’t crushed. Compare sitting below the exhaust of a Saturn V rocket being launched. One would feel the heat… and much of the momentum.
Displaced gas molecules need to go somewhere, and if they can’t move out of the column then they remain within the column – so the column gains mass when a lighter gas is added to the column.
For the same reason, pilots are not starved of oxygen when the plane accelerates by all the air pushing to the back of the cabin. The air has nowhere to go, so it stays put.
Pierre-Normand
Thanks for the comments and interest.
Glad the balloon image is useful.
The plane and floating balloon are both additional and so (assuming no acceleration up or down) their weight will, at equilibrium (theoretical here), add a tiny tiny (i.e. negligible) +ve amount to total pressure at global scales.
It is easier to visualize for floating on water … if we place a big heavy boat in a swimming pool the water level rises (the weight of water displaced is equal to the weight of the boat) and the water pressure at the bottom of the pool rises across the entire pool bottom (not just below the boat).
Thanks Douglas in Norway. This is also useful. Though for the the analogy to be closer we would need to sink the boat (while sealing its surface to preserve buoyancy) and tether it to the bottom of the pool. The effect of the tension of the rope on the bottom of the pool would however seem like a localized decrease in the pressure on the bottom (compensated ‘globally’ by an increase of the uniform water pressure at the bottom due to a lengthening of the water column). This seems opposite to the effect that we seek to explain in the case of the localized increase of atmospheric pressure consequent on localized surface evaporation. So I am puzzled.
The pool image was simply to help show how the effect on pressure is spread out over the entire system. The weight of the volume of water displaced (the addition to pressure) will be more if we tether the still buoyant boat at the bottom of the pool as more water is displaced (the pool water level is even higher).
The original point was simply to highlight that local weight and local pressure are different.
I remember in school physics we did lots of questions on what happens to water levels (on pool sides or on the side of boats) when a boat drops weights out, when it drops tethered anchors, when it hauls in fish, etc.
OK, I think I finally got an intuitive handle on the evaporation/pressure process. The tethered helium balloon or or tethered sunken boat are good analogies to the increasingly moist air above a large forest (where the air was initially dry). I was just misled about the nature of the ‘tether’. It isn’t a fix mechanical tether but a transient inertial one. First, the added water vapor mass lengthens the atmospheric column and this has two initial effects.
It indeed increases the ground level pressure (just as is the case with the tethered boat that displaces water and thereby lengthens the effective column) and it makes the moist air buoyant as a result of its decreasing density.
But the lift of a very widely spread and thick sheet of air is a slow process. There is no solid tether restraining it but there is an inertial one, exerted mostly by the dry air above and around the moist air sheet. Just like a balloon that we cut free of its tether, the buoyant force makes it slowly rise — and similarly the moist air sheet slowly contracts and thickens (thus gaining a net upward motion). The buoyant force thereby communicates upward momentum to the moist sheet. As a mechanical reaction, the surrounding dry air must acquires a downward momentum of the very same magnitude. This momentum is transmitted down to the ground in the form of a transient increase in pressure (just as in the airplane analogy).
This process goes on so long as continued evaporation from below replenishes moisture within the thickening moist sheet. So, the inertial ‘tether’ isn’t ‘pulling’ on the ground at all. Rather it is resisting the buoyant ascent of the moist air sheet though compensating its upward momentum gain with a downward momentum of the surrounding air, which, in turn, contributes to the increasing pressure at the bottom of the sheet (and around it) as it transfers momentum back to the ground.
A related pair of questions that you may enjoy to consider (key to biotic pump) are “why do clouds not fall”? and “where is the weight of the resulting water droplet felt when water condenses as a drop … and what is the implication for pressure below?”
The drops are “falling” (or held aloft by updrafts).
The effect on weight and pressure are analogous to the evaporation story, only now we are removing not adding (so local pressure now decreases), at terminal velocity the weight of the drop is balanced by a drop-centered force that is shared over a large region).
When you grow your own forest from bare paddocks, everything changes around you. You’re not in a green paradise, even with a moso forest, and you need to worry about infestations, the wrong kind of fire etc. But you are certainly in a better place. I find it hard to believe the changes are reserved to the ground and micro-climate.
I know that Australia had horrific droughts etc before deforestation, and I also favour vigorous forest industries even in old growth forest. But let’s have the forests. Before there was Big Green there was Conservation. Lets chop down the wind turbines and use the fabulous wealth potential of fossil fuels to conserve our forests much better than we have done. We don’t have to exploit forests less, just better.
Gum trees, exotic bamboos, lumps of black coal, money, prime agricultural land…each is a resource and should be valued and conserved. Environmentalism, whatever else it is, is not Conservation.
Remember Conservation?
Let’s be quite clear, David Springer:
The GH advocates claim that the “greenhouse gas” water vapour leads to warmer surface temperatures – like about 25 degrees warmer for average WV concentration, but perhaps only 10 degrees warmer in drier regions like hot deserts / sarc.
The real world evidence in a study now published in the Appendix of this book shows (with statistical significance) that our intuition was right all along and WV does in fact lead to lower surface temperatures for the reasons explained in great detail in my book.
I wonder if the ghost of Bradfield were ever raised in Australia, what inland forests could do to climate of the interior?
Douglas in Norway said: Hi Stefan ”The real question is which is the cause and which the consequence. If we put forests in the Sahara would they water themselves?”
Hi Douglas
the case is as:” which came first, the chicken or the egg?”
The fact is: clouds avoid deserts, but go from the sea into areas where is topsoil moisture and water storages = vegetation. b] if you provide water to grow trees in the desert -> clouds would start going there.
2] Sahara was forested, savannas, with lots of lakes and creeks. BUT, the mongrels invented how to produce fire artificially – scorched the vegetation and the rain-clouds stopped coming. b] If the people chop the forest in Brazil – rain will stop coming
3] deserts ”repel” clouds, or if clouds ever get there – the reflection of sunlight from the sand; with secondary reflection, clouds are lifted very high – high clouds don’t produce rain – even if starts raining – the raindrops evaporate before reaching the ground, because of very dry air, evaporation is high.
4] therefore: if they turn some rivers inland in Australia – to drain the floodwater inland, would soften/ wet the air -> trees would grow. Also, if they turn Congo river to drain the floodwater north – trees would grow in Sahara, clouds will start coming and climate will improve. Unfortunately, now the world’s elite con the people that the real climatic changes and the phony GLOBAL warming are one and the same thing… nothing constructive would be done… that’s terrible crime
have look this: http://globalwarmingdenier.wordpress.com/5floods-droughts-we-dont-need-to-have/
Hi Stefan
I use a cartoon of the chicken and egg when I present this.
I think you are probably right. That is also what the biotic pump seems to imply (the forces are potentially large enough). But it is not the conventional view. That means we could (in theory) test it. And I’d like to see that done (insofar as we can without destroying additional forests! there may be data).
Thanks for the link … here is one for you:
http://blog.mongabay.com/2010/10/20/which-came-first-the-forest-or-the-rain/
Douglas in Norway | April 18, 2014 at 7:45 am said: ”That means we could (in theory) test it. And I’d like to see that done (insofar as we can without destroying additional forests!”
Happy Easter Dough!
Forest likes/ needs: H2O&CO2 and sunshine. Not necessary to be high in the mountains; Brazil is most of it flat land, not much higher than sea-level.
forest doesn’t like frequent fires. Human made all the deserts on the planet by tubing two sticks. Human is powerful enough to destroy the climate – human is also powerful enough to improve the climate and vegetation – but nobody is talking about that one… because everybody is busy blaming the ”essential CO2”… tragic.
All it needs is; make new dams, to save the storm-water; water improves from extreme to mild climate -> trees start to grow everywhere. That’s most important for the tropics and subtropics. H2O + CO2 = forests
Hi Stefan
In my line of work we talk a lot about forest loss and restoration. We can fix it (different problems and underlying causes in different places, but most can be addressed, though some such as land-use in Madagascar are difficult).
What is less clear is whether there will be sufficient motivation to act. I do hope so, and I also hope that it is something that people will support through their elected governments, so much need for information sharing and discussion.
Everything you always wanted to know about the derivatives of the thermodynamic state variables for moist air is probably in this ( paywalled ) paper:
P.W. Egolf, B. Frei, R. Furter, Thermodynamics of moist air: contribution to error estimates, Applied Thermal Engineering, Volume 20, Issue 1, January 2000, Pages 119.
Abstract
In several articles and books on thermodynamics, equations describing the behaviour of unsaturated moist air are available. On the other hand, to our best knowledge, a summary of the thermodynamic functions together with all their derivatives is lacking. Individual equations contained in the list of equations in this article are useful for numerous applications in the field of heat transfer and thermodynamic processes of humid air. They can also be applied to other examples, e.g. to construct diagrams which describe various classes of other vapours, such as of solvents. In particular, the derivatives yield a solid basis for error estimates of the related thermodynamic processes. An example describing a dew point measurement to determine the relative humidity of moist air is discussed. It demonstrates how the theory can be applied by readers who are interested in applying the results to interpret their experimental data.
Keywords
Moist air
Thermodynamic function
List of derivatives
Thermodynamic processes of humid air
Error estimates
Dew-point measurement
Copyright 1999 Elsevier Science Ltd. All rights reserved.
Good also for numerical solution methods and for calculating responses in a selected thermodynamic state property as other properties change.
The results in that paper can be generalized by the methods presented in notes here and here.
thanks Dan
I can access that paper.
The final link however will not open for me.
Douglas, here’s the link:
http://edaniel.files.wordpress.com/2011/01/implicitfunctiontheory03.pdf
Can’t find the problem with the comment. It was rejected several times when I initially tried to post it, so there’s something in that ASCII that’s not right.
By the way, those of you interested in these topics may also like this recent blog on the same theme:
http://blog.cifor.org/22060/report-forests-may-play-bigger-role-in-rainfall-than-estimated#.U1JzGVcfOmT
Douglas,
Here’s a recent paper in which formulation of the interfacial exchange / transfer terms are discussed. https://www.sintef.no/project/CO2%20Dynamics/publications/ergaccept.pdf
I’m not saying it’s the best or that the references cited are the best available. There are hundreds of papers like this and this one is as good starting point as any. You can work backward from the citations here, if you’re interested. The use of the entropy inequality has proven to be especially useful in the continuum mechanics approaches to the issue. And, that approach was one of the reasons that it took some time to sort out development of the fundamental continuum equations for materials with significant internal structure and responses. Even the mechanicians struggled with this. Questions about material frame indifference, even for simple materials, arose off and on for a while.
In particular, the lack of hyperbolicity, which is one of the focuses of the paper, was first identified ca 1973 and we finally got the paper published in 1978; Characteristics and Stability Analyses of Transient One-Dimensional Two-Phase Flow Equations and Their Finite Difference Approximations ( paywalled ) It was an extremely controversial, and very divisive, issue at the time, but is now well accepted.
Accepted on a theoretical basis, but exactly what it means relative to, especially, numerical solutions of the model equations continues to be investigated to this day. G. L. Browning and H. O. Kreiss have investigated the issue relative to some GCM model equations. And it seems to be somewhat controversial in this arena, too. All kinds of fixes have been proposed over the decades, and these investigations also continue to this day. Any kind of diffusion ( PDE or FDE ) will change the problem.
The multi-phase, multi-physics, multi-scale thermal sciences are fun :-)
Great – thanks Dan!
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