[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

[AFPhys]

for your ping lists?

[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.

[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.

[AFPhys]

Links to Proceedings of National Academy of Sciences paper - - -

Abstact below - paper is free, and linked at: http://www.pnas.org/content/early/2011/02/16/1100371108.abstract

Global CO₂ rise leads to reduced maximum stomatal conductance in Florida vegetation

1. Emmy I. Lammertsma^a,¹,
2. Hugo Jan de Boer^b,
3. Stefan C. Dekker^b,
4. David L. Dilcher^c,¹,
5. André F. Lotter^a, and
6. Friederike Wagner-Cremer^a

+ Author Affiliations

1. ^aPalaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht University, 3584 CD, Utrecht, The Netherlands;
2. ^bDepartment of Environmental Sciences, Copernicus Institute, Utrecht University, 3508 TC, Utrecht, The Netherlands; and
3. ^cDepartment of Biology, Indiana University, Bloomington, IN 47405

1. Contributed by David L. Dilcher, January 11, 2011 (sent for review October 19, 2010)

Abstract

A principle response of C3 plants to increasing concentrations of atmospheric CO₂ (CO₂) is to reduce transpirational water loss by decreasing stomatal conductance (g_s) and simultaneously increase assimilation rates. Via this adaptation, vegetation has the ability to alter hydrology and climate. Therefore, it is important to determine the adaptation of vegetation to the expected anthropogenic rise in CO₂. Short-term stomatal opening–closing responses of vegetation to increasing CO₂ are described by free-air carbon enrichments growth experiments, and evolutionary adaptations are known from the geological record. However, to date the effects of decadal to centennial CO₂ perturbations on stomatal conductance are still largely unknown. Here we reconstruct a 34% (±12%) reduction in maximum stomatal conductance (g_smax) per 100 ppm CO₂ increase as a result of the adaptation in stomatal density (D) and pore size at maximal stomatal opening (a_max) of nine common species from Florida over the past 150 y. The species-specific g_smax values are determined by different evolutionary development, whereby the angiosperms sampled generally have numerous small stomata and high g_smax, and the conifers and fern have few large stomata and lower g_smax. Although angiosperms and conifers use different D and a_max adaptation strategies, our data show a coherent response in g_smax to CO₂ rise of the past century. Understanding these adaptations of C3 plants to rising CO₂ after decadal to centennial environmental changes is essential for quantification of plant physiological forcing at timescales relevant for global warming, and they are likely to continue until the limits of their phenotypic plasticity are reached.

Paper (PDF):

http://www.pnas.org/content/early/2011/02/16/1100371108.full.pdf+html

[r9etb]

Plants eat plant food.... and eat more of it when more is available. Who’da thunk it?

[r9etb]

Plants eat plant food.... and eat more of it when more is available. Who’da thunk it?