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

[RegulatorCountry]

This is science?

I've taken to calling it "Political Science."

[Ernest_at_the_Beach]

Reading thru Archibald's paper...to the Summary page...will try to get that from the PDF:

**********************************EXCERPT**************************************

Summary

1. Adopt the correct science

- the world is cooling due to the Sun

- the atmosphere needs more CO2, not less

2. US energy independence

- install coal-to-liquids plants

- replace coal-fired power stations with nuclear

3. Leapfrog existing nuclear technology

- go straight to thorium breeder reactors with no long term waste.

[Ernest_at_the_Beach]

www.davidarchibald.info.....PDF's

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

Regarding CO2:

Failure to Warm
An entertaining narrative - highly recommended

[Ernest_at_the_Beach]

A 2 page PDF from Archibald....will catch a couple of paragraphs:

Warming or Cooling?

The whole story in 800 words

*********************EXCERPTS********************************

David C. Archibald 2008, “Warming or cooling?”,

Oil & Gas Journal, v.106 no.30 (Letters, August 11)

Warming or cooling?

The first thing to be aware of is that the warming effect of carbon dioxide is strongly logarithmic. Of the 3° C. that carbon dioxide contributes to the greenhouse effect, the first 20 ppm has a greater effect than the following 400 ppm. By the time we get to the current level of 384 ppm, each 100 ppm increment will produce only about 0.1° of warming. With atmospheric carbon dioxide rising at about 2 ppm per annum, temperature will rise at 0.1° every 50 years.

If that is true, you will ask, how does the Intergovernmental Panel on Climate Change (IPCC) get its icecap-melting figure of 5° for doubling of the preindustrial level to 560 ppm? An equation called the Stefan-Boltzman equation tells us that in the absence of feedbacks, doubling would produce a rise of 1°. The IPCC climate modeling assumes that the feedback from this rise will be positive; that is, that the extra heat will cause more water vapor in the atmosphere, which in turn will cause more heat to be trapped, and the system compounds away until 1° gets turned into 5°. As described, the Earth’s climate would be tremendously unstable, prone to thermal runaway at the slightest disturbance.

The real world evidence says the opposite. In late 2007, a Dr. Roy Spencer of the University of Alabama published a paper analyzing data from the Aqua satellite. Based on the response of tropical clouds, Dr. Spencer demonstrated that the feedback is negative. He calculates a 0.5° warming for a doubling of the preindustrial carbon dioxide level. Global warming is real, but it is also minuscule. Atmospheric temperature rose 0.7° in the 20th century; it has also fallen by the same amount in the last 18 months. Global warming, as caused by carbon dioxide, will be lost in the noise of the system.

[Marine_Uncle]

"- go straight to thorium breeder reactors with no long term waste."
Hmmmm. But that could lead to a mine shaft race. Let me see Cobalt Thorium G

[DeltaZulu]

I personally welcome our new plant overlords :)

[Cacique]

It just so happens I am a political scientist. And a few of us do try to stick to things like cause and effect and empirical evidence and a reproducible hypothesis even as difficult as that is in the social sciences. Galileo and Machiavelli are rolling in their graves. Agenda driven dribble is not science nor never will be.

[TigersEye]

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.

I am sure that one thing is known. They don't vary much. If they change from season to season there isn't much they can tell us about long term changes in growing conditions.

[Mr. K]

This is their new theory to explain all the global warming I have had to shovel out of my driveway this year

[SunkenCiv]

Thanks AFPhys.

[AFPhys]

Abathar -the important effect here has nothing to do with the plant directly cooling in any way. Paul51 had a good synopsis in his post#7. Ernest_at_the_Beach post#24 has a good piece of the puzzle there, too. Since there are other posters who may like to see this, I will ping them here, too ... Let me go back to first principles:

Everyone agrees that doubling CO2 by itself will not induce warming of more than about 1C. The important process that has been postulated by the “warmers” is that an increase of Carbon Dioxide will induce the “positive feedback” of increasing water vapor in the atmosphere, and this in turn causes an amplified “greenhouse effect” as alloysteel points out. The warmers have incorporated no significant negative feedbacks in their hypothesis.

This research turns that paradigm completely upside down since it shows the plants in Florida have been adapting to the increased CO2 by lowering the number of stomata they carry - thus lowering the amount of water vapor they return to the atmosphere. By the way, there is a picture I am going to bring into my next post - so take a look at it - The change of stomata was very dramatic, not minor.

If this is shown to be a worldwide effect - quite likely in my estimation - it will explain the lowering humidity in the upper atmosphere as CO2 has been increasing over the last half century, as shown in the graph I included in my first comment. In this way, plants have been providing a negative feedback with increasing CO2 instead of the strictly positive feedback that has been incorporated in the computer models and other AGW theory.

My eyeballing of the data makes it appear that the total effect of increasing CO2 is likely to be nearly neutral with respect to temperatures... How it will affect rainfall and other aspects of climate long term is less clear. Since there are two major types of plants using different types of photosynthesis (”C3” vs “C4”), increased CO2 and lower humidity may favor a re-balancing of the vegetative types, and I have no good handle on how that would play out.

In any event, this research showing a strong negative feedback on humidity, and thus temperature, with increased CO2 due to the way plants adapt, completely turns the whole field upside down. Honest computer models will have to attempt to incorporate the way plants change over time and the way they regulate humidity in the atmosphere.

This research represents a serious groundbreaking development in the field.

[AFPhys]

The change in the stomata was not minor: here is a picture from the article -

"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."

[Freedom_Is_Not_Free]

Great post, thank you. I understood that better than the posted article.

It is intuitive that their can be no C02-catalyzed feedback loop causing global air temperatures to rise linearly as this would rapidly go only one way and there would be no possibility for an ice age to occur.

The very fact that ice ages come and go suggests conclusively that there is no continuous feedback loop but that the earth’s atmosphere has a buffer system that allows a cold climate to warm and a hot climate to cool. The sun dominates this process, not greenhouse gases.

Anyway, thanks for a great post.

[AFPhys]

“In late 2007, a Dr. Roy Spencer of the University of Alabama published a paper analyzing data from the Aqua satellite. Based on the response of tropical clouds, Dr. Spencer demonstrated that the feedback is negative. He calculates a 0.5° warming for a doubling of the preindustrial carbon dioxide level.”

-—<>-—<>-—<>-—<>-—<>-—<>-—

I have studied Dr.Spencer, et al’s work on this, and find it quite compelling. However, there were some errors (admitted by the authors) in the paper, which are being addressed. Indeed, Spencer has recently written a follow on paper that seems to rehabilitate most of the ‘07 paper and its conclusions, but the jury is still out. The suggested cloud mechanics is a very powerful mechanism for negative feedback that is not currently included in the warmist’s hypotheses or models.

This is a good place to point out that a change in the albedo (brightness, reflectiveness) of Earth that would result from a change in cloud cover of only 1-2% can explain ALL of the temperature change we have experienced since 1900. We clearly do not know historical cloud coverages that well, so it is conceivably the sole reason for the change, or it may have played no part.

The IPCC has always admitted it has very little understanding of clouds and the way they affect temperature, so the Spencer proposition is extremely important new science that must be addressed further. This research showing negative feedback due to vegetation changes is an additional new piece of science which must be addressed.

Regardless, as some posters here have pointed out, given the evident long-term stability of Earth’s temperature, it seems clear that there must be negative feedbacks with respect to CO2 as well as many other inputs, including solar radiation. The warmists attempts to deny this are rapidly being quashed by research such as this.

[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

[AFPhys]

The other paper at Proceedings of the National Academy of Sciences... http://www.pnas.org/content/early/2011/02/16/1100555108.abstract

Abstract:

Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO₂

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

+ Author Affiliations

1. ^aEnvironmental Sciences, Copernicus Institute for Sustainable Development, Utrecht University, 3508 TC, Utrecht, The Netherlands;
2. ^bPalaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht University, Budapestlaan 4, 3584 CD, Utrecht, The Netherlands; and
3. ^cDepartment of Biology, Indiana University, Bloomington, IN 47405

1. Contributed by David L. Dilcher, January 24, 2011 (sent for review October 19, 2010)

Abstract

Plant physiological adaptation to the global rise in atmospheric CO₂ concentration (CO₂) is identified as a crucial climatic forcing. To optimize functioning under rising CO₂, plants reduce the diffusive stomatal conductance of their leaves (g_s) dynamically by closing stomata and structurally by growing leaves with altered stomatal densities and pore sizes. The structural adaptations reduce maximal stomatal conductance (g_smax) and constrain the dynamic responses of g_s. Here, we develop and validate models that simulate structural stomatal adaptations based on diffusion of CO₂ and water vapor through stomata, photosynthesis, and optimization of carbon gain under the constraint of a plant physiological cost of water loss. We propose that the ongoing optimization of g_smax is eventually limited by species-specific limits to phenotypic plasticity. Our model reproduces observed structural stomatal adaptations and predicts that adaptation will continue beyond double CO₂. Owing to their distinct stomatal dimensions, angiosperms reach their phenotypic response limits on average at 740 ppm and conifers on average at 1,250 ppm CO₂. Further, our simulations predict that doubling today's CO₂ will decrease the annual transpiration flux of subtropical vegetation in Florida by ≈60 W·m⁻². We conclude that plant adaptation to rising CO₂ is altering the freshwater cycle and climate and will continue to do so throughout this century.

PDF of paper at:

http://www.pnas.org/content/early/2011/02/16/1100555108.full.pdf+html

[Ernest_at_the_Beach]

Heavy Discussion on the paper at Watts Up With that?:

Negative water vapor feedback in plant evapotranspiration found

[Brad from Tennessee]

Thanks. I get it now.

[TigersEye]

While it is well known that long-lived plants can adjust their number of stomata each season depending on growing conditions, ...

Those pics show about the limit of possible change. Given that plants can alter the size and number of their stomata from season to season it makes any changes over years, centuries or millennium meaningless.

[TigersEye]

In any event, this research showing a strong negative feedback on humidity, ...

Compared to the oceans which cover over 2/3s of the earth?