From NASA Earth Science news: A new NASA computer modeling effort has found that additional growth of plants and trees in a world with doubled atmospheric carbon dioxide levels would create a new negative feedback – a cooling effect – in the Earth’s climate system that could work to reduce future global warming.
The cooling effect would be -0.3 degrees Celsius (C) (-0.5 Fahrenheit (F)) globally and -0.6 degrees C (-1.1 F) over land, compared to simulations where the feedback was not included, said Lahouari Bounoua, of Goddard Space Flight Center, Greenbelt, Md. Bounoua is lead author on a paper detailing the results that will be published Dec. 7 in the journal Geophysical Research Letters.
Without the negative feedback included, the model found a warming of 1.94 degrees C globally when carbon dioxide was doubled.
Bounoua stressed that while the model’s results showed a negative feedback, it is not a strong enough response to alter the global warming trend that is expected. In fact, the present work is an example of how, over time, scientists will create more sophisticated models that will chip away at the uncertainty range of climate change and allow more accurate projections of future climate.
“This feedback slows but does not alleviate the projected warming,” Bounoua said.
To date, only some models that predict how the planet would respond to a doubling of carbon dioxide have allowed for vegetation to grow as a response to higher carbon dioxide levels and associated increases in temperatures and precipitation.
Of those that have attempted to model this feedback, this new effort differs in that it incorporates a specific response in plants to higher atmospheric carbon dioxide levels. When there is more carbon dioxide available, plants are able to use less water yet maintain previous levels of photosynthesis. The process is called “down-regulation.” This more efficient use of water and nutrients has been observed in experimental studies and can ultimately lead to increased leaf growth. The ability to increase leaf growth due to changes in photosynthetic activity was also included in the model. The authors postulate that the greater leaf growth would increase evapotranspiration on a global scale and create an additional cooling effect.
“This is what is completely new,” said Bounoua, referring to the incorporation of down-regulation and changed leaf growth into the model. “What we did is improve plants’ physiological response in the model by including down-regulation. The end result is a stronger feedback than previously thought.”
The modeling approach also investigated how stimulation of plant growth in a world with doubled carbon dioxide levels would be fueled by warmer temperatures, increased precipitation in some regions and plants’ more efficient use of water due to carbon dioxide being more readily available in the atmosphere. Previous climate models have included these aspects but not down-regulation. The models without down-regulation projected little to no cooling from vegetative growth.
Scientists agree that in a world where carbon dioxide has doubled – a standard basis for many global warming modeling simulations – temperature would increase from 2 to 4.5 degrees C (3.5 to 8.0 F). (The model used in this study found warming – without incorporating the plant feedback – on the low end of this range.) The uncertainty in that range is mostly due to uncertainty about “feedbacks” – how different aspects of the Earth system will react to a warming world, and then how those changes will either amplify (positive feedback) or dampen (negative feedback) the overall warming.
An example of a positive feedback would be if warming temperatures caused forests to grow in the place of Arctic tundra. The darker surface of a forest canopy would absorb more solar radiation than the snowy tundra, which reflects more solar radiation. The greater absorption would amplify warming. The vegetative feedback modeled in this research, in which increased plant growth would exert a cooling effect, is an example of a negative feedback. The feedback quantified in this study is a result of an interaction between all these aspects: carbon dioxide enrichment, a warming and moistening climate, plants’ more efficient use of water, down-regulation and the ability for leaf growth.
This new paper is one of many steps toward gradually improving overall future climate projections, a process that involves better modeling of both warming and cooling feedbacks.
“As we learn more about how these systems react, we can learn more about how the climate will change,” said co-author Forrest Hall, of the University of Maryland-Baltimore County and Goddard Space Flight Center. “Each year we get better and better. It’s important to get these things right just as it’s important to get the track of a hurricane right. We’ve got to get these models right, and improve our projections, so we’ll know where to most effectively concentrate mitigation efforts.”
The results presented here indicate that changes in the state of vegetation may already be playing a role in the continental water, energy and carbon budgets as atmospheric carbon dioxide increases, said Piers Sellers, a co-author from NASA’s Johnson Space Center, Houston, Texas.
“We’re learning more and more about how our planet really works,” Sellers said. “We have suspected for some time that the connection between vegetation photosynthesis and the surface energy balance could be a significant player in future climate. This study gives us an indication of the strength and sign of one of these biosphere-atmosphere feedbacks.”
Patrick Lynch
NASA’s Earth Science News Team
The amazing thing to me is the hubris of people who believe that they can accurately model something as complex as the climate of the Earth. It seems that almost everyday we hear of another factor or feedback that is not part of the model. No clouds? No problem! No vegetation? No problem!
As a scientist myself, I am just baffled as to how any of this is considered to be good science or to follow the scientific method.
Now, lets see how well this new model correlates with known temperature measurements in the past…. Until this is done, I will give this model just as much weight as any other prophecy of the future.
ding ding ding
“Danger Will Robinson, Danger!”
“new NASA computer modeling effort”
Another attempt to muddy the waters just about covers it.
“Scientists agree that in a world where carbon dioxide has doubled – a standard basis for many global warming modeling simulations – temperature would increase from 2 to 4.5 degrees C (3.5 to 8.0 F). (The model used in this study found warming – without incorporating the plant feedback – on the low end of this range.) ”
Always nice to know where they are starting from, in their assumptions while constructing the model.
It’s still just a model. Give me some new data, analysis, and interpretation…then I might be impressed
1.94 degrees C? Seems to me that they are still fudging the numbers to make it look like a doubling causes more than 1 degree C….oh well, they are at least starting to back away from the vehicle (runaway train meme).
“Scientists agree” — I almost stopped reading there. Blech.
Anyhoo, there’s also the wee factor of growth requiring energy. I reeelly wonder if that’s in their ramshackle “energy budget” model.
As I posted elsewhere, don’t forget to deduct 1.9°C from all current and recent records: http://www.canadafreepress.com/images/uploads/ball120610-2.jpg
Sorry, stopped reading there. They have their meme and they aren’t going to let go!
DaveE.
Anthony,
And NASA think this is ‘New’! We have been saying it for years – but I would put it more strongly: Plants through photo-transpiration cooling, which is enhanced by more CO2, VETO any CO2 claimed atmospheric warming (by whatever mechanism).
See pdf in WA2010News27 via comments in ClimateRealists thread –
http://climaterealists.com/index.php?id=3307
or via news archive on http://www.weatheraction.com
Cheers Piers from COLD UK
REPLY: See also this story –
http://wattsupwiththat.com/2008/06/08/surprise-earths-biosphere-is-booming-co2-the-cause/
wonder what this Guardian story was – it should be in Guardian’s “money” section, but can be found nowhere and has no cached version:
A working life: The climate change consultant
14 hours ago
The map was created by running a climate prediction model, HadCM3. Out of a total of 34 model runs, 23 showed the global average temperature rising above 4C …The Guardian
http://www.guardian.co.uk/money/2010/dec/07/working-life-climate-change-consultant
clicking on the URL gets the Guardian site with:
“Sorry – we haven’t been able to serve the page you asked for”
could it have been related to this?
30 Nov: Reporting Climate Science: Leon Cliffard: Models warn of 7C dangerous climate change by 2090
The researchers used two computer climate models, HadCM3-QUMP and MAGICC, to run multiple ensemble simulations. “The evidence available from new simulations with the HadCM3 GCM and the MAGICC SCM, along with existing results presented in the IPCC AR4, suggests that the A1FI emissions scenario would lead to a rise in global mean temperature of between approximately 3C and 7C by the 2090s relative to pre-industrial, with best estimates being around 5C,” the researchers conclude in their paper…
CITATION:
Citation:”When could global warming reach 4C?” by RICHARD A. BETTS, MATTHEW COLLINS, DEBORAH L. HEMMING, CHRIS D. JONES, JASON A. LOWE AND MICHAEL G. SANDERSON
Published in Philosophical Transactions of the Royal Society Phil. Trans. R. Soc. A (2011) 369, 67–84 doi:10.1098/rsta.2010.0292
http://www.reportingclimatescience.com/news-stories/article/models-warn-of-7c-dangerous-climate-change-by-2090.html
30 Nov: Royal Scoiety Publishing: When could global warming reach 4°C?
Richard A. Betts1,*, Matthew Collins2, Deborah L. Hemming1, Chris D. Jones1, Jason A. Lowe1 and Michael G. Sanderson1
Author Affiliations
1Met Office Hadley Centre, Fitzroy Road, Exeter EX1 3PB, Devon, UK
2College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
*Author for correspondence (richard.betts@metoffice.gov.uk).
http://rsta.royalsocietypublishing.org/content/369/1934/67.full
I trust “computer models” like i trust “camwhores ” on 4 chan.
(A lied to Canadian reporting in)
[d]
I don’t trust ANYTHING NASA says these days. It now appears that their “new life form” is crap, too: http://hotair.com/archives/2010/12/07/scientists-nasas-alleged-discovery-of-arsenic-based-life-is-crap/
OK. I went back to it & reached this…
which again stopped me in my tracks!
I thought that one of the things that happened with increased CO2 was that stomata closed leading to increasing efficiency of water usage, ie a decrease in transpiration.
So many contradictions.
DaveE.
Nice. Very nice. And some pinhead is going to take credit for some new original thought? Well, at least they’re only a decade or so behind poor dumb laymen bloggers and commentators.
“We’re learning more and more about how our planet really works,” Sellers said. “We have suspected for some time that the connection between vegetation photosynthesis and the surface energy balance could be a significant player in future climate.”
I hate to be reduced to schoolyard vernacular, but with this, I’ve got to say, ‘no $hit, Sherlock, what was your first clue?’
Are they really this slow? Or are they just milking the grant gravy train?
Why the Hell was this not a given from day one?
I mean … greenhouses … you pump them full if CO2 for a reason.
I have noticed that is quite cool and pleasant under may shade tree during the hot summer months.
If anyone else has a shade tree you might think about the idea of co-authoring a paper with me on how vegetation cools down the planet, …and leads to pleasant afternoon naps.
The statistics part may be a little tough as we track how hot it is in the sun compared to the shade and how fast the nap phase sets in as a function of full sun – vs full shade temperature differential– but if we do enough test cycles we can tough it out and get the numbers. …and it will be real data. We can even do a cold beer test to see how fast it affects the nap cycle…
Serious science — for serious folks! We don’t need no steenking models!
Damn, got up to get another beer and rid myself of one and Piers Corbyn beat me too it! I should learn to refresh before I post. At least I can reinforce what Piers stated. This thought has been posited in many skeptical sites for a long time. I can’t be sure, but I think it has been posited here on a few occasions. I suppose I could go look, but I’m betting someone will have it at the ready before I could find it.
More modelling. Keeps plenty of families in govt. employ, good luck to them.
Seems reaonable that if you change a highly reflective surface to a dark surface you’d expect positive feedback.
So how come, when vegetation (dark) encroaches on the Sahara (light) the area actually gets cooler?
The problem is, mother nature doesn’t play XBox games and she refuses to conform.
FTA: ““This feedback slows but does not alleviate the projected warming,” Bounoua said.”
Wrong. By their own words, it alleviates it by -0.3 deg globally and -0.6 deg over land. He could have said “does not alleviate significantly“, or “does not stem the tide of…”, but it does alleviate it, the only question being, to what extent?
From dictionary.com:
al·le·vi·ate
/əˈliviˌeɪt/ Show Spelled[uh-lee-vee-eyt] Show IPA
–verb (used with object), -at·ed, -at·ing.
to make easier to endure; lessen; mitigate: to alleviate sorrow; to alleviate pain.
Now I get it! They’re trying to explain why they’ve failed to model climate before!
Guess what chasps! You’ve failed again!
DaveE.
WillR:
I ave made a few such studies myself. I have tested different types of trees with different concentrations of foliage. I also found with certain types of trees it is warmer under them than the surrounding area during the cold months. I would need an observer to monitor the sleep states I am able to reach during my experiments though!
Is the question before the jury whether or not Earth is warming?
Or is the question whether humans will cause disastrous warming by emissions of carbon dioxide?
Someone (who?) has decided to focus on the consequences of humans causing a doubling of the atmospheric concentration of CO2. Does anyone know that it is possible to cause a doubling? At what rate would we have to use coal, oil, gas, wood (others?) to accomplish this? Is it realistic?
Can models such as the one discussed work with lesser concentrations? Assume the concentration were to be cut to 200 ppm; what then?
Funny how stable our bimodal climate has been during this ice age period…surprisingly stable for such a runaway prone planet. Also funny how everyone is suddenly finding negative feedbacks as the climate models diverge from reality…LOL! Even more funny is how cold it is Cancun…who would have guessed, GAIA has quite the sense of humour! I will laugh with her…
Mike Davis says:
December 7, 2010 at 7:50 pm
WillR:
I ave made a few such studies myself. I have tested different types of trees with different concentrations of foliage. I also found with certain types of trees it is warmer under them than the surrounding area during the cold months. I would need an observer to monitor the sleep states I am able to reach during my experiments though!
I’m excited! I think we have a basis for collaboration here. I too have noticed that during the winter months it is warmer under say a dense pine or cedar tree here in our cold climate. I never thought of monitoring the sleep states — that is a great idea! Will that prove anything about the climate — or should we not be concerned about that? Data is data right? A bit of statistical analysis could prove something I’m sure! PCA is a good technique I’m told… No signs, no decimals though I have enough trouble with the Natural Numbers… ok?
We just need a couple more “researchers” to widen the data pool…
tregembo says on December 7, 2010 at 7:54 pm
Indeed. And when South America joined with North America and prevented the flow of water from the Pacific to the Atlantic that must have caused a big change in climate, yet it found a new (possibly bimodal) state.
It is clear that the work wanker applies to climate alarmists …
Has it already been said that model results are not proof?