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
More CO2, more plants and trees, more sunshades for land surface, more biosols, more clouds, more cooling. Nature is notorious for self-regulation of the planet’s climate. No need for global climate junkets and meetings to “fight man-made warming”.
LT I thought your nom-de-plume was a disguise for an old git, but judging from your last two posts it seems you really are a teenager. A grown-up would know that computer models can never replace real science in this sector, as they do not deliver real information about the environment, and that claiming they do so, without being candid about the gaps in the models or the range of assumptions on which they depend, is indeed hubris.
The opposite (not obverse, which means the other side of the same coin, for your information) of hubris is not defeatism but realism; understanding one’s own limitations and working within them to produce work that is, dare I say, sustainable.
Go get an education and come back when you have learned something about life. You will need to stop being lazy, though, if you want to learn anything – trolling on websites is no life for an active young person.
LazyTeenager says:
December 8, 2010 at 12:44 am
“The trend in science is to try and solve more and more difficult problems. Many of those problems involve complex systems with lots of moving parts. Typically they are becoming too complex for an individual person to describe or reason about. That’s why computer models are the only way forward. ”
Okay, let’s ignore that.
The NASA people do what any propagandist would do when seeing their methods of persuading the populace failing – scale back their claims one way or the other to regain some trust, to be able to attack again later.
You can fudge the numbers any way you like with the models.
The guys from NASA are now right up there for comedy with infants attempting to herd cats.
Ah so they added another fudge factor into their model and it gave the wrong answer so they decided it had to be the plants because they had not included them. /sarc off
you poor americans, you pay for this €rap.
LazyTeenager says:
December 8, 2010 at 12:44 am
You said it “try” to solve. Models are one way forward but they are not a solution and they have to be rigorously VV&T’ed. None of the current climate models is any of this.
Lazy Teenager is about right.
LazyTeenager says:
December 8, 2010 at 12:32 am
Piers Corbyn says:
December 7, 2010 at 7:01 pm
Mon dieu vous êtes un idiot. Piers Corbyn has more usable brain up his backside than you have demostrated here in total. You are so incredibly stupid as to be not worth this reply but I’ll struggle on. Do you understand or even know of Piers? Many of the people who read and comment on this site ( Anthony included) are highly intelligent, very high qualified and hugely respected scientist. Take your bile and stupidity elsewhere you are adding no value here.
Interesting modelling. It looks like they are counting only on land-based increased bio-mass. What about the oceans?
Another thing. The large forrests of the north have increased during modern times if they increase even further, it is not a wild guess that also their aerosol production will increase similarly. What about the efect of these natural aerosols, = cooling? Anyone knows?
Cripes I step out for a minute and the trolls creep back in
You have no credibility here lazy teen and Watts should ban you after he burns through
your proxy IP
MOMMA’S BOY
[d]
So, ignoring the modelling aspect completely, the picture here is exactly what we and NASA ought to be looking at to identify climate change. If the plants are responding to CO2, we should see a global greening. If there are actual climate changes (NOT temperature rises alone) then surely we will see the movement of climate zones. If the climate is changing without affecting the actual climate zone anywhere on the planet, then it ain’t changing much.
Wow. Its time to drop the pretense, and the gloves, and come out swinging at these fraud artists. Seriously. Time to cancel PhD degrees, time to start pulling public funding from campuses that perpetuate the sleaze, time to start charging scientists and bureaucrats with a litany of crimes against public order. Carpetbagging is still a crime.
LazyTeenager says:
December 8, 2010 at 12:32 am
Piers, like the scientist he most assuredly is, made public this knowledge many (many) moons ago.
So, yes, if you had written down, in a public forum at the very least, that you predicted “heads” before the event then you would be afforded some respect by your peers and others.
As it is; FAIL.
Having re-read the rot…
“there are a zillion confounding factors and no one knows what the sum total result is”
yet….
“computer models are the only way forward”
CFD? Chaos? Much?
Here endeth the piling on.
“Without the negative feedback included, the model found a warming of 1.94 degrees C”
which is 1.64 deg with the feedback.
Finally they have a model for this planet. In todays world the solar input is amplified 2.45 by the climate system. A CO2 doubling, 3.7 W/m2, then becomes 9 W/m2 at the surface, which drives the temperature 1.65 deg C.
So here is all the model you need: Output = Input * 2.45
There is something wrong here.
Ultimately, this model result is saying increased evapotranspiration (evaporation by plants) results in a cooling feedback.
This is not what the current climate models assume. They are are assuming that increased evaporation puts more water vapour into the atmosphere, rainfall and clouds increase by less and, on net, there is an increased water vapour level overall – which increases temperatures by close to 2.0C (per 1.0C increase caused by GHG doubling).
Don’t tell me this is the first climate model to include the initial cooling effect of evaporation. Otherwise, why are they going against the current theoritical consensus.
[The result says that plants use water more efficiently (less evapotranspiration per individual plant) but the vegetation grows more efficiently and we end with an increased level of vegetation which then results in more evapotranspiration overall].
@ur momisugly phlogiston, December 8, 2010 at 12:23 am
“Like I’ve said in several comments on previous threads – CO2′s effect on climate is about biology first, physics second.”
Yeah – but for biology, one’s gotta get one’s hands dirty at some stage, and even go out into raw nature, yeccch, so that’s out.
And physics is waaayyy too hard – everybody knows that.
So why not nice computer modelling, like playing on X-Box: we all know how to do that, and one can write lots of e-mails while working …
😉
The prediction of lesser effect over the ocean than over land makes me suspicious that the net cooling is understated. Most photosynthesis on earth is done by marine phytoplankton.
LazyTeenager says:{December 8, 2010 at 12:44 am}
” Typically they are becoming too complex for an individual person to describe or reason about. That’s why computer models are the only way forward.”
If individuals cannot describe or reason about a system, how can they accurately write a program for a computer model? You miss the simple point that computers do things faster than what can be done by hand but can only do them as good as the program itself. Always remember GIGO.
Plants capacity to absorb CO2 as a sink must increase with a lag effect as plants increase in number or size follows the increase in CO2. Does anyone know how long this lag is?
A year or two ago, I read an article that said that the temperature within trees (trunk? folliage?) was remarkably stable. I don’t remember whether they were talking about summer or wintern or both. I searched Google and couldn’t find it. I assume it’ll crop up again.
[reply] Leaves: http://www.nature.com/news/2008/080611/full/news.2008.884.html RT-mod
Why use models? A: They’re cheap and easy to manipulate. Easy to find enough space for a desk, monitor and keyboard, just need a bit of a.c. power. Real experiments need a lab, equipment, workshops, field time, calibrations, someone with some practical ability. And after all that money you get awkward data that often doesn’t make any clear sense so you can’t publish it. It’s so much neater if you run a model.
Wobble – you’re right. It IS back to front. That’s because they know what the solution is!
And Lazy Teenager – if the problem is too complex for an individual to describe or reason about then it isn’t a problem worth bothering anyone else about.
I speculate, though could be wrong, that this is, knowingly or otherwise, the first stage of the retreat from catastrophic global warming ideology.
addendum – when they say it is “completely new”
Somehow that is highly doubtful.
“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.”
In my experience the last snow to melt, in spring, is found in forests and not open country. This makes me question the idea that forest canopy acts only as a positive feedback.
LazyTeenager says:
December 8, 2010 at 12:44 am
Mike O says:
December 7, 2010 at 6:36 pm
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.
As a scientist myself
————
Well it looks to me like you are not keeping up to date.
The trend in science is to try and solve more and more difficult problems. Many of those problems involve complex systems with lots of moving parts. Typically they are becoming too complex for an individual person to describe or reason about. That’s why computer models are the only way forward.
The obverse of what you describe inaccurately as hubris is defeatism, stagnation and lack of imagination.
——-
Hey, LazyTeenager welcome back!
First: ‘Mike O’ makes a valid point of hubris towards the modeller’s of Earths’s climate, it is in fact a point of debate among many people (scientists and non-scientists) as to whether the climate system is just too chaotic, non-linear, etc, etc, etc, to be modelled with our current neophyte understanding. This also extends to our ability (or lack thereof) to create a meaningful “code”, equations, or computer language to encompass our climate, what some would argue is an ‘unbounded’ process/system.
Second: we have been repeatedly told, since the late 1990’s that these models are “robust” and can accurately represent past climate when hindcasting, and do offer reliable projections of future probablities/possibilities (all evidence to the contrary). So much so that $$$Billions$$$ have been spent globally. None of the “predictions” or “probabilities” have come to pass; the “hubris” comment by ‘Mike O’ stands validated. No self respecting person (let alone scientist) familiar with GIGO would have ascribed the veracity to their climate projections that these guys have. I’m sorry (or not) but this has just been going on for too long and methinks you come to the game too late (if in fact you are a teenager).
Third: your “obverse” comment, seeing how the models were/have never been validated/accurate/reliable, on many levels, should not be ‘defeatism’ but pragmaticism (ok I just made that word up), should not be ‘stagnation’ but mobilization as data and methods were openly shared, and as shortcomings/errors were acknowledged and corrected instead of being denied and hidden. Lastly: ‘lack of imagination’ would be replaced with collaboration of imagination between sceptics, modellers, et al from many disciplines ensuring that the scientific method was adhered to and that the results were actually supported by observational data.
On my planet you don’t make extrodinary claims without extrodinary evidence and it is this modelling evidence that is extrodinary, in the obverse: extrodinarily lacking.
Now I’m going to hop back into my hot-air balloon and head back to OZ, as the climate there is much more stable, see ya there! 😉