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
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.
========================================================
What Tom said, LT.
A collection of computer game programmers, will not make them any smarter.
As soon as the ‘collection’ knows enough to program it, all of the individuals will also.
You can’t program the computer games either.
So… if mankind increases CO2 output, vegitation benefits and increases the negative fedbacks?
DUH!
The more we learn the less we know. What began as a well defined problem – insolation, albedo and greenhouse gas forcings – is diverging in all directions. It is like pulling a thread, then watching as the thread bifurcates into 2, then 4, then 8 smaller threads. Pretty soon you are pulling at a barely countable tangle of threads hanging off threads hanging off threads.
A quick recap of climate influencing parameters so far, include: TSI which varies differently at different wavelengths, solar wind, cosmic ray flux, black soot, white aerosols, high level cloud feedback, low level cloud feedback, the interaction of aerosols on cloud genesis, the interaction of GCR’s on cloud genesis, water vapour cycles, effect of warming on water vapour cycles and the effect of this on cloud formation, effects of co2 on plant growth, on transpiration and water vapour cycles and the effects of all these on temperature patterns and cloud formation, shifts in ocean conveyor systems that may or may not result from climate changes, effect of changing ozone levels. . .
And while all these (and much more) are interacting in ways only dimly understood, the earth is still rotating on its axis, the insolation still sweeps the surface from a few hundred to over one thousand watts per square meter; temperatures rise and fall in myriads of places from -60c to +120c. Yet we are attempting to smooth all this into averages of averages of averages, and by examining temperature anomalies measured in hundreths of a degree, forecasting what the climate will be a hundred years into the future.
It is time these modellers came clean and admitted it will be decades, if ever, before they can confidently predict the future climate.
[NASA’s earth model here does not even rotate about an inclined axis. Nor do they vary cloud cover over the years as humidity is (claimed to change), much less over a year’s climate cycle. But that may be “accurate enough”, do their climate models rotate at at? Do they vary their distance from the sun annually? Vary the local albedo regionally, monthly, annually as we see in this animation? Robt]
Sorry for all of the warm mongers but I have been saying this!
I specifically mentioned the cooling effect of Co2 caused by increased vegetation. The other cooling effect of CO2, namely the radiative cooling effect is still also being largely ignored. There is apparently even another cooling effect due to some interaction in the upper atmosphere.
The question is: what is the net effect of the warming and cooling of Co2?
I CAN GUESS THAT IT IS ZERO OR CLOSE TO ZERO….
For example, if you look at the development of the temperatures of the average yearly minimum temperatures at weather stations and if you put all the evidence together:
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
The guys at NASA are VERY slow on the uptake. This effect has been known for years.
Photosynthesis is a COOLING process. Water drawn up into the leaves to react with CO2 to produce starch and O2 is then transpired as water vapour through the stomata of the leaves. This is of course a cooling effect – like evaporating alcohol on the skin. The global cooling effect is massive.
Not only is it a cooling effect but exactly counteracts increasing CO2 – more CO2 more photosynthesis more cooling!
Including plant growth as a negative feedback in models means nothing. One would need to program it in for it to be in the model which means this is a created effect.
It is not surprising that there would be a negative effect, but the effect needs to be detected and described in the real world before it has any meaning in a model. Creating a negative feedback in a model says absolutely nothing about the real world.
Which came first, the real world or the model? The real world.
Which one carries and weight scientifically? The real world. The model = 0.
Amazing, plants use less water with higher Co2, yet increase evapotranspiration on a global scale and create an additional cooling effect.
Others have pointed this out as well above. It brings this to mind:
From Canada to the Caribbean: Tree leaves control their own temperature
June 11th, 2008
The temperature inside a healthy, photosynthesizing tree leaf is affected less by outside environmental temperature than originally believed, according to new research from biologists at the University of Pennsylvania.
Surveying 39 tree species ranging in location from subtropical to boreal climates, researchers found a nearly constant temperature in tree leaves. These findings provide new understanding of how tree branches and leaves maintain a homeostatic temperature considered ideal for photosynthesis and suggests that plant physiology and ecology are important factors to consider as biologists tap trees to investigate climate change.
Tree photosynthesis, according to the study, most likely occurs when leaf temperatures are about 21°C, with latitude or average growing-season temperature playing little, if any, role. This homeostasis of leaf temperature means that in colder climates leaf temperatures are elevated and in warmer climates tree leaves cool to reach optimal conditions for photosynthesis. Therefore, methods that assume leaf temperature is fixed to ambient air require new consideration.
From: http://www.sciencecentric.com/news/article.php?q=08061131
So climate sensitivity to a CO2 doubling is coming down (1.9 C) and then you add in one known negative feedback (-0.6 C) to get a sensitivity of 1.3 C net. But the science is settled.
co-author Forrest Hall : “We’ve got to get these models right, and improve our projections, so we’ll know where to most effectively concentrate mitigation efforts.”
Are you sure? Mitigate what? Has it occurred to you that what was happening with CO2 might be exactly the right thing for the planet and humans without any mitigation at all? Increasing population needs increasing food production from limited cropland and limited water. Remember the big flap over food production and predictions of mass starvation a while back? Worldwide agricultural yields per hectare have increased dramatically in the last several decades. Very few give any credit to the increase in atmospheric CO2. Like Rodney Dangerfield, CO2 gets no respect. If CO2 was much of a warming factor, we sure could use some more of in down here in Florida right now. Our reputation is almost ruined. Another couple of years like this and I may as well move back north.
“pat says:
December 7, 2010 at 7:03 pm
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”
Google has it pat – I suspect it was taken down as it’s a shooting gallery for sceptics 🙂
http://webcache.googleusercontent.com/search?q=cache:http%3A//www.guardian.co.uk/money/2010/dec/07/working-life-climate-change-consultant
h/t Fran Codwire @Bishops Hill
LazyTeenager says:
December 8, 2010 at 12:32 am
“Let’s throw a dice, I bet heads, I win the bet, I boast that I knew all along that it was going to be heads. Am I telling the truth?”
Whose heads are rolling on those dice?
So essentially something is amiss right?
Since 1750 CO2 levels have gone from 280 to about 390 ppmv. Apparently back in the hay day of life was a partyyy temperature was normal. I kid you not it says so on longrangeweather.com historical graphs. 230 years later, around 1987/88, we were back to normal again, albeit a higher normal, apparently.
Back in 1880, however, temperatures wasn’t normal, but below normal, apparently.
280 times 2 equals 560. So in about 170 ppmv more we should see these abnormally high average global temperatures. It only took us 260 years to get to 390 ppmv and going from -.04 in 1880 to +.04 (the latter is from our trusty albeit manipulated wikipedia) 2010.
Since every climate hobnob seem to be using the linear crap, like NOAA uses in their graphs, it’ll take several hundred years to get a doubling of CO2.
But since the temperatures didn’t get back to normal, from the “normal” of 1750, in 1988 which happened to be at about 350 ppmv CO2 levels (and how arbitrary isn’t that IPCC chooses the levels the same year IPCC was spawned the new hippie church) and slightly above normal (1961-1990) temperature levels.
So which doubling is everyone meaning when they say a doubling of the CO2 levels? IPCC at one time meant from about 1990 levels and temperatures which included the already about 1° C from, first 1750, then 1850, then 1880, now about around 1900.
If we scrap the linear crap and go by the logarithmic stuff with CO2, it’ll take us a frakking eternity to raise the temperature another puny °C.
But of course I forgot to take into account the only non-linear function of CO2, which, apparently, is that human emitted CO2, from coal and oil but not breath, is mysteriously different and frakking super charged as an infrared, probably whole spectrum, emitter. o_O
Whatever solar radiative energy a leaf’s photosynthesis uses to chemically convert into potential energy is solar energy that does not and cannot contribute to global warming.
“do their climate models rotate at at? Do they vary their distance from the sun annually? ”
DAFS : do a search. This code has been available for years now. The code browser
is very nice and people should do more reading and less speculation. I cannot be the only person on WUWT who knows how to read code. It’s only 100K or so LOC
doesnt take very long.
SUBROUTINE ORBIT (OBLIQ,ECCN,OMEGT,DAY,SDIST,SIND,COSD,LAMBDA) 1,1
!@sum ORBIT receives the orbital parameters and time of year, and
!@+ returns the distance from the sun and its declination angle.
!@+ The reference for the following calculations is: V.M.Blanco
!@+ and S.W.McCuskey, 1961, “Basic Physics of the Solar System”,
!@+ pages 135 – 151.
!@auth Gary L. Russell and Robert J. Suozzo, 12/13/85
C**** Input
!@var OBLIQ = latitude of tropics in degrees
!@var ECCEN = eccentricity of the orbital ellipse
!@var OMEGT = angle from vernal equinox to perihelion in degrees
!@var DAY = day of the year in days; 0 = Jan 1, hour 0
C**** Constants:
!@param VERQNX = occurence of vernal equinox = day 79 = Mar 21 hour 0
C**** Intermediate quantities:
!@var PERIHE = perihelion during the year in temporal radians
!@var MA = mean anomaly in temporal radians = 2 JDAY/365 – PERIHE
!@var EA = eccentric anomaly in radians
!@var TA = true anomaly in radians
!@var BSEMI = semi minor axis in units of the semi major axis
!@var GREENW = longitude of Greenwich in the Earth’s reference frame
C**** Output:
!@var SDIST = square of distance to the sun in units of semi major axis
!@var SIND = sine of the declination angle
!@var COSD = cosine of the declination angle
!@var LAMBDA = sun longitude in Earth’s rotating reference frame (OBS)
USE CONSTANT, only : pi,radian,edpery
IMPLICIT NONE
REAL*8, PARAMETER :: VERQNX = 79.
REAL*8, INTENT(IN) :: OBLIQ,ECCN,OMEGT,DAY
REAL*8, INTENT(OUT) :: SIND,COSD,SDIST,LAMBDA
REAL*8 MA,OMEGA,DOBLIQ,ECCEN,PERIHE,EA,DEA,BSEMI,COSEA
* ,SINEA,TA,SINDD ! ,SUNX,SUNY,GREENW
C****
OMEGA=OMEGT*radian
DOBLIQ=OBLIQ*radian
ECCEN=ECCN
C****
C**** Determine time of perihelion using Kepler’s equation:
C**** PERIHE-VERQNX = OMEGA – ECCEN sin(OMEGA)
C****
PERIHE = OMEGA-ECCEN*SIN(OMEGA)+VERQNX*2.*PI/EDPERY
C PERIHE = DMOD(PERIHE,2.*PI)
MA = 2.*PI*DAY/EDPERY – PERIHE
MA = MOD(MA,2.*PI)
C****
C**** Numerically solve Kepler’s equation: MA = EA – ECCEN sin(EA)
C****
EA = MA+ECCEN*(SIN(MA)+ECCEN*SIN(2.*MA)/2.)
110 DEA = (MA-EA+ECCEN*SIN(EA))/(1.-ECCEN*COS(EA))
EA = EA+DEA
IF (ABS(DEA).GT.1.D-15) GO TO 110
C****
C**** Calculate the distance to the sun and the true anomaly
C****
BSEMI = SQRT(1.-ECCEN*ECCEN)
COSEA = COS(EA)
SINEA = SIN(EA)
SDIST = (1.-ECCEN*COSEA)*(1.-ECCEN*COSEA)
TA = ATAN2(SINEA*BSEMI,COSEA-ECCEN)
C****
C**** Change the reference frame to be the Earth’s equatorial plane
C**** with the Earth at the center and the positive x axis parallel to
C**** the ray from the sun to the Earth were it at vernal equinox.
C**** The distance from the current Earth to that ray (or x axis) is:
C**** DIST sin(TA+OMEGA). The sun is located at:
C****
C**** SUN = (-DIST cos(TA+OMEGA),
C**** -DIST sin(TA+OMEGA) cos(OBLIQ),
C**** DIST sin(TA+OMEGA) sin(OBLIQ))
C**** SIND = sin(TA+OMEGA) sin(OBLIQ)
C**** COSD = sqrt(1-SIND**2)
C**** LAMBDA = atan[tan(TA+OMEGA) cos(OBLIQ)] – GREENW
C**** GREENW = 2*3.14159 DAY (EDPERY-1)/EDPERY
C****
SINDD = SIN(TA+OMEGA)*SIN(DOBLIQ)
COSD = SQRT(1.-SINDD*SINDD)
SIND = SINDD
C GREENW = 2.*PI*(DAY-VERQNX)*(EDPERY+1.)/EDPERY
C SUNX = -COS(TA+OMEGA)
C SUNY = -SIN(TA+OMEGA)*COS(DOBLIQ)
LAMBDA = 0. ! just to keep the compiler happy
C LAMBDA = ATAN2(SUNY,SUNX)-GREENW
C LAMBDA = MOD(LAMBDA,2.*PI)
C****
RETURN
END SUBROUTINE ORBIT
How is that possible that more trees means less CO2.
Neither the USA, nor New Zealand, both of which have extensive forest farming, are allowed to offest their animal farts against growing more trees; so I don’t see how the Kyoto folks could be wrong on this; maybe this is another NASA GAFF, to go along with their GISS, and of course their latest ARSENILE paper.
Frosty –
many thanx for the link.
This new paper is one of many steps toward gradually improving overall future climate projections,
Zuh? How can they be improved if they’re already completely accurate?
NASA should really try modeling ARSENIC.
While it’s nice they are beginning to get a clue about the negative feedbacks (perhaps sensing a cold shift in the future funding winds…) they are still a couple of orders of magnitude off kilter.
A quick survey of some simple data shows that plants can suck all the CO2 out of the air down to the limits of their ability to live in fairly short order. Plants rule:
http://chiefio.wordpress.com/2010/10/10/got-wood/
Adolf Goreing (ze denier) says:
December 8, 2010 at 2:54 am
“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?”
The influence of aerosols can be positive or negative, noone knows for sure. They are used by the climate modelers as a wildcard and parameterized, so that the value of the parameter maximizes the hindcasting fit. (No joke.) To justify the value you chose, you just have to find the right peer-reviewed paper and say -“Our experiment (read model run) has provided evidence that this author was right in his assessment of the influence of aerosols.” (Obviously, because it made your model fit the temperature history better, this author must be right.)
Perfect post-normal logic.
NASA should develop a computer model that determines the ratio of feces to nerve tissue in the heads of climatologists.
“We’ve got to get the models right. We’ve got to improve our projections…”
If we are confident of improvement, could we not have the courage to upgrade the label to “predictions”.
Well no, it would be unwise to do so. Almost every month a new factor emerges affecting climate and fundamentally challenging the assumptions underlying global climate models. Methane, clouds, ENSO, PDO/AMO, solar cycles now plant metabolism. It is well known that in the past e.g. Devonian, Carboniferous, plant and tree physiology and anatomy – such as leaf width – have responded and interacted dynamically with atmospheric CO2 levels (Beerling and Berner 2005, pnas, sorry no link). There is no reason why such interaction should not be a continuing factor in climate today.
The whole concept of an all inclusive all singing all dancing global climate model is unrealistic and unachievable, vacuous and built on hubris. This point has been articulated frequently here and bears repeating.
Real climate science bites off a chewable chunk, such as Bob Tisdale’s masterly analysis of the Pacific ENSO system, Paul Vaughan’s discovery of climate correlatons with astrophysical cycles, Tsonis’ development of nonlinear chaotic models which predict climate’s interaction with oceanic cycles, and testable hypotheses about global temperature regulation by latitudinal movements of ITCZ cloud bands by Stephen Wilde and Willis Eschenbach.
In a knowledge structure like any structure the foundations must be built first.
Hate this expression, but what else can you say?
“Well, Duh!”
We get here all the time people claiming that with CO2 only about one molecule in 2500 in the atmosphere; it couldn’t really do anything. Well a million divided by 390 is actually 2564, and the cube root of that is about 13.7.
So a CO2 molecule has to look past about 13.7 layers of molecules in any direction to find another one like it.
Or think of a thin “plane” of atmospheric atoms, the CO2 molecules in that plane are about 13.7 molecules apart. So imagine if all other atmospheric gas molecules were totally transparent; and all CO2 molecules were totally black and opaque. Well it seems that a photon shooting up from the surface might never hit anything opaque in that layer; mostly they would go right through in between the CO2 black spots. But what about the next layer, and then the next ?
So if you looked upwards, would the sky be bright or would it be black. This is sort of like the question; why is the night sky dark instead of bright; with all those infinities of bright stars out there, there must be one in every direction. So why would CO2 block anything ?
Well it’s time to hit the beach; as in sandy beach; and bring your stick, so you won’t get swept off your feet in the surf; and you might want to scratch some doodles in the sand.
So if you go down to just below the high water line, where the waves occasionally wash up the beach, look and see if you can find a grain of sand, that is still dry, where the water just squeezed in between the grains, and didn’t hit some sand grains.
So aren’t we forgetting that LWIR Radiation is a wave just like the ocean waves on the beach.
Just picture this; the LWIR radiation that is looking for a CO2 molecule to absorb some 15 micron wavelength energy.
Now that is 15,000 nano metres wavelength.
If you are reading this on a new Intel i-7, six, or maybe 4-core processor computer, the Intel chip in there has about 32 nm minimum dimensions, like gate length. Drain to source distances might be down in that size range.
That means you can fit about 470 of those gate lengths into the space of one wavelength of CO2 ready LWIR radiation.
To those chip transistors, those waves lapping on the silicon beach look like ordinary radio waves. The AMD 6-core chips are done with about 45 nm critical dimensions.
Now radio waves are easily described in terms of Maxwell’s equations for the Electromagnetic Field, and like the shore waves lapping on the beach, they can wash over all those sand grains, and not leave a single one of them dry.
Well you only have to scale this picture down; not even to the Intel chip scale, to realize that the EM wave that represents the LWIR radiation emitting from the earth surface is not going to leave any of those CO2 molecules dry either; they are way smaller than the Intel transistors, that themselves see the surface radiation waves as huge in wavelength.
So you see that it is only a matter of scale; that LWIR radiation has a very well defined energy density that you can calculate from Maxwell’s equations, and it is going to hit every single one of those CO2 molecules in the amosphere.
Now when the molecule grabs some of that wave energy, it is certainly going to take it in the form of a quantized energy “packet”; but it is going to grab some.
I have a very interesting Optics Text Book, called “Optics of the Electromagnetic Spectrum.” And this whole Text book discusses all of the well known Optical phenomena described by ray optics, and the Fresnel reflection laws, and Snell’s Law, but it discusses and experiments with them in the laboratory, using microwave sources, and cm wave “optical” structures, so you can actually observe the wave interractions of long wavelenght “light” at a scale that the student can actually see.
We shouldn’t get too set in our ways of thinking; sometimes another view is more illuminating.
All of the standard optics text book stuff on geometrical optics, Polarisation and the like can be experimented with at microwave frequencies, so you can actually poe around in it at laboratory scale dimensions
“Without the negative feedback included, the model FOUND a warming of 1.94 degrees C globally when carbon dioxide was doubled.”
There’s something wrong with this sentence, but I cant quite put my finger on it …