Climate forcing due to optimization of maximal leaf conductance... - Temp goes down with higher CO2

National Academy of Sciences (will be linked downthread when available) ^ | March, 2011 | Prof. David Dilcher

[AFPhys]

Negative water vapor feedback in plant evapotranspiration found

Rising CO2 is causing plants to release less water to the atmosphere, researchers say

Study Finds That CO2-Induced Warming Causes Atmosphere To Hold Less Water Vapor

Stomata are structures that allow plants to exchange gases with the air. Contemporary plants in Florida have fewer stomata than their ancestors did a few decades ago.

BLOOMINGTON, Ind. — As carbon dioxide levels have risen during the last 150 years, the density of pores that allow plants to breathe has dwindled by 34 percent, restricting the amount of water vapor the plants release to the atmosphere, report scientists from Indiana University Bloomington and Utrecht University in the Netherlands in an upcoming issue of the Proceedings of the National Academy of Sciences (now online).

In a separate paper, also to be published by PNAS, many of the same scientists describe a model they devised that predicts doubling today’s carbon dioxide levels will dramatically reduce the amount of water released by plants.

The scientists gathered their data from a diversity of plant species in Florida, including living individuals as well as samples extracted from herbarium collections and peat formations 100 to 150 years old.

“The increase in carbon dioxide by about 100 parts per million has had a profound effect on the number of stomata and, to a lesser extent, the size of the stomata,” said Research Scientist in Biology and Professor Emeritus in Geology David Dilcher, the two papers’ sole American coauthor. “Our analysis of that structural change shows there’s been a huge reduction in the release of water to the atmosphere.”

Most plants use a pore-like structure called stomata (singular: stoma) on the undersides of leaves to absorb carbon dioxide from the air. The carbon dioxide is used to build sugars, which can be used by the plant as energy or for incorporation into the plants’ fibrous cell walls. Stomata also allow plants to “transpire” water, or release water to the atmosphere. Transpiration helps drive the absorption of water at the roots, and also cools the plants in the same way sweating cools mammals.

If there are fewer stomata, or the stomata are closed more of the day, gas exchange will be limited — transpiration included.

“The carbon cycle is important, but so is the water cycle,” Dilcher said. “If transpiration decreases, there may be more moisture in the ground at first, but if there’s less rainfall that may mean there’s less moisture in ground eventually. This is part of the hyrdrogeologic cycle. Land plants are a crucially important part of it.”

Dilcher also said less transpiration may mean the shade of an old oak tree may not be as cool of a respite as it used to be.

		IMAGE: Researchers extract stomata-bearing leaves from a peat formation in Florida. At some sites, the peat was estimated to be as much as 150 years old. Click here for more information.

“When plants transpire they cool,” he said. “So the air around the plants that are transpirating less could be a bit warmer than they have been. But the hydrogeologic cycle is complex. It’s hard to predict how changing one thing will affect other aspects. We would have to see how these things play out.”

While it is well known that long-lived plants can adjust their number of stomata each season depending on growing conditions, little is known about the long-term structural changes in stomata number or size over periods of decades or centuries.

“Our first paper shows connection between temperature, transpiration, and stomata density,” Dilcher said. “The second paper really is about applying what we know to the future.”

That model suggests that a doubling of today’s carbon dioxide levels — from 390 parts per million to 800 ppm — will halve the amount of water lost to the air, concluding in the second paper that “plant adaptation to rising CO₂ is currently altering the hydrological cycle and climate and will continue to do so throughout this century.”

Dilcher and his Dutch colleagues say that a drier atmosphere could mean less rainfall and therefore less movement of water through Florida’s watersheds.

The Florida Everglades depend heavily on the slow, steady flow of groundwater from upstate. The siphoning of that water to development has raised questions about the future of the Everglades as a national resource.

###

Dilcher’s Dutch coauthors for the two papers were Emmy Lammertsma, Hugo de Boer, Stefan Dekker, Andre Lotter, Friederike Wagner-Cremer, and Martin Wassen, all of Utrecht University in Utrecht, Netherlands. The project received support from Utrecht University’s High Potential research program.

To speak with Dilcher, please contact David Bricker, University Communications, at 812-856-9035 or brickerd@indiana.edu. To speak with any of the Dutch coauthors, please contact Emmy Lammertsma, Utrecht University, at 31 (0) 64 137 6175 or e.i.lammertsma@uu.nl.

“Global CO₂ rise leads to reduced maximum stomatal conductance in Florida vegetation” Proceedings of the National Academy of Sciences (online), vol./iss. TBD

“Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO₂” Proceedings of the National Academy of Sciences (online), vol./iss. TBD

[AFPhys]

Note in the graph below, the tremendous negative correlation of humidity with rising CO₂ the last years, most noticeable in the upper atmosphere. These articles (accepted for publication but not yet published) strongly suggest the reason: a strong negative correlation of CO₂ with humidity due to plant evapotranspiration, thus ameliorating positive feedback effects of CO₂ itself.

Now we know why the CO2 driven models have not been able to predict temperatures.

I consider this to be the DEATH KNELL for CO2 caused Global Warming.

[AFPhys]

additional article: http://www.c3headlines.com/2011/03/peer-reviewed-study-finds-that-co2-induced-warming-causes-atmosphere-to-hold-less-water-vapor.html

Peer-Reviewed Study Finds That CO2-Induced Warming Causes Atmosphere To Hold Less Water Vapor

Read here. IPCC Climategate science predicts that as CO2 increase in atmosphere, the resulting warming will increase the atmosphere's water vapor levels, which will cause more warming (a positive feedback).

Unfortunately for the IPCC, that major tenet of the AGW hypothesis has not worked so well, as the below atmospheric humidity chart from www.climate4you.com reveals. (click on image to enlarge)

Now a new study discovers why the water vapor levels have not increased as predicted. Lammertsma et al. determine that as CO2 levels rise, vegetation responds in two ways: one, by absorbing more CO2 for food production, and two, releasing less water vapor. The scientists calculate that with this vegetation response, a doubling of atmospheric CO2 to 800ppm levels will cut in half the amount of atmospheric water vapor - that's called a major, natural, NEGATIVE feedback.

This negative feedback that will have a huge impact on the atmosphere's water vapor content is not included in any climate models that the IPCC, NASA and NOAA utilize. This may be a major reason why these models have continually failed in their predictions. Thus, current models' estimates of climate sensitivity evaporate, or if you prefer, transpire...or, is climate sensitivity kind of a climate model 'vaporware' chartacteristic.

"As carbon dioxide levels have risen during the last 150 years, the density of pores that allow plants to breathe has dwindled by 34 percent, restricting the amount of water vapor the plants release to the atmosphere, report scientists.....“The increase in carbon dioxide by about 100 parts per million has had a profound effect on the number of stomata and, to a lesser extent, the size of the stomata,” ...“Our analysis of that structural change shows there’s been a huge reduction in the release of water to the atmosphere.”...If there are fewer stomata, or the stomata are closed more of the day, gas exchange will be limited.....suggests that a doubling of today’s carbon dioxide levels — from 390 parts per million to 800 ppm — will halve the amount of water lost to the air, concluding in the second paper that “plant adaptation to rising CO2 is currently altering the hydrological cycle and climate..." [Emmy Lammertsma, Hugo de Boer, David Dilcher, Stefan Dekker, Andre Lotter, Friederike Wagner-Cremer, and Martin Wassen 2011: PNAS1 and PNAS2]

Additional CO2-water vapor, failed-prediction and peer-reviewed postings.

March 04, 2011 at 05:21 AM | Permalink

[steelyourfaith]

 

Beam me to Planet Gore !

[AFPhys]

for your ping lists?

[E. Pluribus Unum]

As carbon dioxide levels have risen during the last 150 years, the density of pores that allow plants to breathe has dwindled by 34 percent, restricting the amount of water vapor the plants release to the atmosphere...

And since water vapor contributes 95% of the atmospheric greenhouse effect...

[AFPhys]

Great addition to the thread

[paul51]

more CO2..more global warming. Less water vapor..less global warming. The plants are regulating the global temp changes that would result from more CO2. The global warming scientists somehow didn't expect that.

[Halgr]

BTTT

...to be used later to counter the enviro wackos.

[Paco]

Uh, are you out of your mind? Lest you forget: "If you look at the peer reviewed scientific literature, the debate is over." - Al Gore

[Islander7]

I consider this to be the DEATH KNELL for CO2 caused Global Warming.

You are right, now we are gonna freeze becasue of CO2. Go figure!

Frankly, I can not see any way that less than one tenth of one percent of atmospheric gases (CO2) can cause any significant changes.

The sun is the primary driver of our climate.

[Beowulf]

Thanks for the ping.

[Abathar]

"“When plants transpire they cool,” he said. “So the air around the plants that are transpirating less could be a bit warmer than they have been. But the hydrogeologic cycle is complex. It’s hard to predict how changing one thing will affect other aspects. We would have to see how these things play out.”"

Pardon me, but if the air is cooler that means the plant itself would have to be absorbing the heat from the air, which in turn would make the plant warmer, is that correct?

It's been a while since my thermodynamics courses in school, but just like an air conditioner the thermal energy has to go somewhere, so if a plant is warming the air around it then it has to be shedding that heat FROM something, and if it is cooling the air then it the opposite would also be true, wouldn't it?

It just seems that what this guy just said is backwards to me is all.

[PapaBear3625]

Dilcher and his Dutch colleagues say that a drier atmosphere could mean less rainfall and therefore less movement of water through Florida’s watersheds.

No matter WHAT happens, these guys have to spin it as having potentially horrible consequences.

The bulk of Florida's rainfall comes from water that evaporated from the Gulf of Mexico, and has nothing to do wit any plants.

Less plant transpiration means that plants will be much more resistant to drought conditions. This means better harvests worldwide. Plants need CO2. The less they have to work in order to get enough CO2, means more energy for growth.

[Para-Ord.45]

How can there be a + feedback loop is CO2 is linear and not exponential?

[alloysteel]

Wot?

Higher CO2 levels have a NEGATIVE effect on water vapor in the atmosphere?

Somebody is talking out their rectal orfices once again. Really COLD weather decreases the relative humidity of air, as well as the absolute amount of water vapor as a part of the atmosphere. But really cold weather also increases the uptake of CO2 by water, and holds the CO2 as carbonic acid, until warmed again.

Really hot weather INCREASES the relative humidity of the air, in the presence of an evaporative source, and also the capacity of the atmosphere to HOLD a much higher absolute quantity of water vapor. Simultaneously, the warmer water RELEASES its CO2 content, as carbonic acid disassociates, and as a released gas coming out of solution, evaporates from any body of water in which it has been held.

Now, if there is no evaporative source to carry water vapor into the atmosphere, the relative humidity falls to extremely low levels, as the absolute quantity of water vapor is reduced. Water vapor, as a gas, is LIGHTER than the mixture of N2 and O2 that makes some 98+% of the atmosphere, while CO2 is HEAVIER, and tends to settle in lower parts of the atmosphere. Why do plants get so stunted and sparse at high altitude? Not because of lack of water, but because of lack of a very basic building block for growth, CO2.

Somebody tell me what I have wrong here. And somebody please, PLEASE, why this pile of balderdash is supposed to change that previously held conception. Cause and effect seem to be entirely transposed, because the right questions are NOT being asked.

[Cacique]

"100 parts per million"

If that is the increase in CO2 that is causing this, they better look for another cause. That is such an insignificant amount as to be laughable. Nothing above shows a clear cause and effect connection. The almost untraceable increase in CO2 is being correlated without any justification. This is science?

[Venturer]

I used to not trust Lawyers, then politicians, then Doctors, now its scientists.

[Brad from Tennessee]

While individual plants produce less water vapor as a result of a rising CO2 level, the increased CO2 would also increase the size and number of plants (and leaves). So it may be a wash.

[Ernest_at_the_Beach]

Just found this at Climate Depot:

*****************************************

'Increased atmospheric Co2 will increase agricultural productivity...The ideal atmospheric CO2 level is a minimum of 1,000 ppm' Read David Archibald's full presentation here.

[Marine_Uncle]

We need to figure out how to pump more CO2 into the air. Not an easy task that is for sure.