Sensitive side (from the NASA Global Climate Change Website)
By Rosemary Sullivant,
NASA Jet Propulsion Laboratory
A little extra carbon dioxide in the air may, unfortunately, go further towards warming Earth than previously thought. A team of British and U.S. researchers have uncovered evidence [1] that Earth’s climate may be up to 50 percent more sensitive to long-term increases in atmospheric carbon dioxide than current climate models predict. The reason for the underestimation, they say, may be due to long-term changes in ice sheets and vegetation that are not well represented in today’s global climate models.Just how much will global temperature rise in response to increases in atmospheric carbon dioxide? This is one of the key questions that climate scientists need to answer. According to the climate models used in the most recent report from the Intergovernmental Panel on Climate Change (IPCC), doubling the amount of carbon dioxide in the atmosphere from pre-industrial levels is expected to warm Earth by about 3 degrees Celsius (5 degrees Fahrenheit), once the atmosphere and oceans spend a few years or decades adjusting and reaching a balance.
But according to a recent study by a team of researchers that includes Gavin Schmidt of NASA’s Goddard Institute for Space Studies, Earth’s climate is also influenced by other, much slower processes. These include changes in ice sheets, vegetation and aerosols, for example, that take place over hundreds and thousands of years.
Because of their complexity and long timescales, these processes are almost impossible to integrate into today’s climate computer models. As a result, it has been difficult to know just what their effect on Earth’s climate sensitivity would be.
To learn more about this sensitivity, Schmidt and his co-authors looked back 3 million years into Earth’s past. They used a computer model that describes the oceans and atmosphere to predict, retroactively, the climate of the mid-Pliocene — a period when both global temperatures and atmospheric carbon dioxide concentrations were higher than today. The model substantially underestimated just how high temperatures would go. When the researchers adapted the model to include the effects of long-term climate changes in vegetation and ice sheets, they were able to get a much closer representation of the warming in the Pliocene era.
The team found that it took much lower concentrations of atmospheric carbon dioxide to recreate the Pliocene’s warm climate than current models — which consider only the relatively fast-adjusting components of the climate — predict. Pliocene carbon dioxide levels are estimated to have been around 400 parts per million by volume (ppmv), while according to current simulations it would take 500 to 600 ppmv of carbon dioxide to bring about the warm temperatures of the Pliocene. As a result, the researchers estimate that Earth’s response to elevated concentrations of atmospheric carbon dioxide is 30 to 50 percent greater than previously calculated. In other words, the climate is more sensitive to carbon dioxide than we thought.
This higher sensitivity of the climate should be taken into account, the team concludes, when targets are set for limiting greenhouse gas emissions. The results of the study appear in Nature Geoscience.
Research paper: [1] Daniel J. Lunt et al., “Earth System Sensitivity Inferred from Pliocene Modelling and Data,” Nature Geoscience, Vol. 3, No. 1 (2010).
PDF Here
Considering the Arctic is declining much faster than expected seems reasonable to suggest greater climate sensitivity.
Who cares about feedback processes that take thousands of years? Will we even be emitting CO2 in a thousand years?
But also, the problem here is that they are just assuming that the warm period of the Pliocene was caused by heightened CO2, and then creating a model fit to the data which supports their preconceived notions. And darn wouldn’t ya know it, they came up with a way to make it “worse than we thought” to.
In the world of real world measurements, I hear Lindzen and Choi have submitted an update of their earlier feedback paper to JGR. They take into account several criticisms but the conclusion isn’t drastically different.
There are millions of things missing from the models. So they locate those missing ones which would increase the AWG case and ignore the missing ones which would decrease the case.
The models are rubbish, that is the problem. We cannot model the Earth because it has too many interdependent systems that act together in a highly non linear fashion over multiple timescales. None of them can be neglected yet most are. You cannot get the correct answer, but you can get the answer you want.
Just keep twiddling those dials Gavin. Eventually you’ll find the perfect iterative world. Shame it works so poorly here.
Interesting…will need to really look into this. Can’t wait to see what the skeptics have to say.
Meanwhile, the NSIDC, on their May update, spoke about the uptick in sea ice going through the Fram Strait since winter has ended. As everyone here knows, this is the main passageway for ice (that isn’t melting outrighit) to leave the Arctic ocean into the N. Atlantic where it melts fast (but not fast enough for the Titanic back in 1912!). Anyway, here’s a great site to get a first hand detailed look at this ice flowing through the Fram Strait. Just go here:
http://ice-map.appspot.com/
Center the page at about 79.5 degrees North, and 2.25 degrees E and zoom in. Very nice shot of the big chunks of ice moving out of the Arctic through the Fram Strait. On the same page, move up to about 83 degrees N and -15 degrees W and zoom into the big melt going on N. of Greenland where winter temps were very warm from the negative AO index. On many days that I checked it this winter, it was in the upper 20’s F in Greenland while it was in the teens in places like Georgia and Alabama. That’s what a negative AO will do!
GIGO. Garbage In Garbage Out. It’s well established that changes in carbon dioxide concentrations lag temperature changes by about 800 years. So the garbage computer models didn’t match data from the real world. Big freakin’ surprise.
It can’t be the models that are wrong because these scientists know more about how nature works than nature itself. /sarc
Is this what happened to cause the MWP? And if so what reversed it?
“…Just how much will global temperature rise in response to increases in atmospheric carbon dioxide? This is one of the key questions that climate scientists need to answer….”
In other words, we have no idea what the correct figure is right now but let’s just bet trillions of dollars on an answer we kind of like anyway.
Just goes to show that even though you can’t model climate 1 year into the future, you can still model climate 3 million years into the past.
Quantum mechanics is probably responsible for this disparity. Even though Schroedinger’s equation is time-symmetric, the quantum phase-space of the past has self-scattered and has collapsed into a single state. The future psi is still unscattered, however, and all future states remain probabilistic. Climate is clearly anti-Hermetian with respect to the time operator. This is why it takes someone brilliant, like an applied mathematician, to understand the true and time-wise asymmetric bound of climate, and to make the kind of robust prediction privileging us here.
This is the sort of convoluted logic one has to resort to when one starts with the mere assumption that CO2 causes warming in the first place.
However I seem to recall that AGW proponents accept that, historically, CO2 levels always followed warming and that only in the past half century or so was that general rule broken by the human contribution.
It’s just an extension ‘ad absurdum’ of the exercise previously carried out whereby the models were ‘adjusted’ to ‘explain’ observed warming ex post facto by simply assuming that CO2 was the primary driver and attaching the required weighting to the CO2 effect to ‘explain’ that warming.
There’s only so far one can go with such assumptions and on the basis of this article things are just getting silly. We cannot safely assume that there are no other significant factors inducing global warming or cooling during such distant times.
Somebody has to say it is worse than we thought:)
These tax leeches have neither sense nor shame.
Real people in the real world are losing their jobs, in part because of escalating energy costs.
Millions of the world’s poorest & most vulnerable are being denied hope not just by kloptomaniac and incompetent dictators (as usual) but by the developed world diverting aid money into crackpot schemes to “save the planet” prompted by little Gavin’s ludicrous bleatings.
So, what does Roy Spencer think of this? Perhaps Schmidt timed it to put this little study out in anticipation of Roy’s book hitting the book stores.
“They used a computer model that describes the oceans and atmosphere to PREDICT”
Yawn! (a little early where I am to even get into sarc mode)
If they can’t explain the “divergence” problem 30 years ago, how can they explain the relationship 3 million years ago? Perhaps I am just being insensitive.
Now what feedbacks does Gavin assume in his computer model? Validation anyone?
Maybe this! Maybe that! Maybe they should stop wasting their time and our money on junk, model based science and give us a freaking break!
Ok, so just to clarify, using the current models of CO2 and Temperature projections retroactively didn’t work for past temperatures and so, instead of perhaps suggesting there was a problem with the theory (in terms of perhaps finding out there is more to the issue) the concentration was on the CO2 issue is “Certainly” correct therefore what can we adjust into the models that fit the theory?
I do not have a lot of experience in climate science currently but reading this article made one eyebrow disappear up into my hairline in incredulity. Is it just me or does anyone else have a problem with the fact that the result of CO2 modeling failing to predict the temperatures of the Pliocene era, the solution was – Co2 causes even more warming o_O ?
As soon as I see the words “computer model”, I shut off. I advise anyone else to do the same. Computer models are useless for predicting warming, cooling, or anything else within the chaos of the climate system.
Were the models any better at handling the real greenhouse gas, H2O, for the Pliocene than they are for the present climate?
The arrogance of these people is astonishing. “They used a computer model that describes the oceans and atmosphere to predict, retroactively, the climate of the mid-Pliocene”
They can’t even tell what the weather will be like next week. Muppets.
Ah yes, the “Computer Model”. I wonder if its the same one Mann uses for his “tree rings”? 😉
I love the smell of desperation in the morning.
So essentially they are trying to mimic the answer they assume are the correct answer.
They don’t really know is the answer is the correct one.
They know the computer model they use should be filled with more variables then they currently fill it with.
Yet they go about fiddling with this and that until they get co2 close enough to the assumed correct answer and then call it the day.
They have a reference picture and they have a machine with which to project a clear and proper image, preferably as close as to the reference picture as possible. However they’ve gotten it into their heads that it’s all about the digital focus that need adjustment, when in fact it’s everything from the magnetic coils to the physical alignment and convergence that is off and is why it is so hard to properly do the focusing. One can do it their way and still end up with an image that looks correct, but that doesn’t mean they adjusted the right variables.
Can they prove they included and adjusted the right variables?
And what is close? I should’ve gotten half of that first price since I almost won. :p
blah, blah, blah, what else is new