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New Climate Models at NSF

The National Center for Atmospheric Research, funded by the National Science Foundtaion, announced today its new climate change model, CCSM3 (Community Climate System Model version 3), now the most accurate and detailed model of atmospheric systems available. The source code for CCSM3 is available for download, as well as component modules for the atmosphere, ice effects, the oceans, and more.

Although the model is publically available today, NCAR researchers have already been hard at work using it to model the effects of increased carbon dioxide.

CCSM3 shows global temperatures could rise by 2.6 degrees Celsius (4.7 degrees Fahrenheit) in a hypothetical scenario in which atmospheric levels of carbon dioxide are suddenly doubled. That is significantly more than the 2 degree Celsius (3.6 degree Fahrenheit) increase that had been indicated by the preceding version of the model.

William Collins, an NCAR scientist who oversaw the development of CCSM3, says researchers have yet to pin down exactly what is making the model more sensitive to an increased level of carbon dioxide. But he says the model overall is significantly more accurate than its predecessor.

"This model makes substantial improvements in simulating atmospheric, oceanic and terrestrial processes," Collins says. "It has done remarkably well in reproducing the climate of the last century, and we're now ready to begin using it to study the climate of the next century."

One of the standard global warming denial attempts is the claim that the problems are artifacts of poor models. As the above shows, the opposite is true. The better we understand the systems at work, the more we see the trouble we're in.


Listed below are links to weblogs that reference New Climate Models at NSF:

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There have been many blog posts about the new release, version 3.0, of the NCAR climate model CCSM3 (Community Climate System Model version 3). It has a few tweaks and gets different results than previous versions. Version 4 will too as will every new... [Read More]

Comments (17)


I think ONE of the main criticisms of the idea of human-caused global warming is that it hasn't risen to the level of a scientific theory yet. Having not read in detail the latest information you've linked to, I would say this is a good sign that we may be moving closer to formulating a meaningful hypothesis. If scientist can create a model that accurately and consistently predicts warming patterns across the globe over the next few years, I would say those holding the "denial" viewpoint should rightfully be put on the defensive. (Then again, not understanding how the computer model works makes any findings more tentative in my mind. Why do I think if future iterations of modeling shows less warming that many people will gloss over those results?)

Of course, your phrasing seems to indicate that you already view their insistence that human-caused global warming is not science yet with quite a bit of skepticism. One of the problems with climatology is that it has become so politicized over the past 15 years. Your attitude towards skeptics may make it harder to prove that humans are demonstrably and significantly warming up the planet much more than would be happening in our absence.

And, of course, there's always the fun problem of trying to figure out a way to reduce the climate impact the species is making on the planet. Kyoto's cutting out Chinese and Indian emissions seems to make that plan a non-starter given their prospective economic growth in the 21st century...


I wish you would give more details, such as the range of scenarios the model produces given various inputs. Your description of the model is worse than useless from the objective of conveying meaningful information.

As any thinking person knows, CO2 is not the only greenhouse gas in the atmosphere. A model with high predictive value takes into account the different gases involved. Such a predictive model would weight the importance of the various important greenhouse gases in a realistic manner. Unfortunately, the model you describe seems to suffer from oversensitivity to one particular greenhouse gas, CO2. And what do you know, CO2 is also the political favorite of many political activists.

Welcome to the blogosphere. Keep it real.

I've never personally been keen to either deny or accept global warming as fact, as science in this stage isn't like that -- it's a best guess situation. We are getting better at predictions, but we're not accurate enough, in my opinion, to implement draconian measures like the Kyoto Protocols and very likely cripple our economy.

There is a lot of work going on looking for alternative means of decreasing the amount of CO2 presently in the atmosphere, as well as attempts to decrease the amount of CO2 we create without slapping down stict quotas we need to adhere to. Sinking CO2 into the ocean is one possibility in the former, and of course, fusion and solar power look promising -- down the road -- in the later.

My point being, yes, it's scary, but if we humans caused this problem, we can certainly fix it, as well. And without punishing measures like in Kyoto.

Insufficiently Sensitive:

Somehow the learned proprietors of the "most accurate and detailed model of atmospheric systems available" failed, in their dramatic statement, to offer the number of years it would take to double the CO2 in the atmosphere at current conditions. Is that tomorrow, or three hundred years from now?

Nor did they add perspective on the relative amounts of all other greenhouse gases. The most prevalent of all, I understand, is the evil chemical compound H2O.


...in a hypothetical scenario in which atmospheric levels of carbon dioxide are suddenly doubled.

I suggest we not do this "sudden doubling" thing. Whose idea was that?

Since we're frightening ourselves with silly scenarios, what does the model predict for the sudden halving of atmospheric carbon dioxide? That's almost as likely to happen next week...

GT writes:Why do I think if future iterations of modeling shows less warming that many people will gloss over those results?

Some undoubtedly would, although we wouldn't here at WC. Most likely, we would express some relief that we (the global we) have more time to fix climate problems than we thought. I'm a little less sure how to respond to the assertion that global warming isn't yet science, when the vast majority of climatologists (along with broader bodies such as the NSF) clearly do. What would your criteria be for considering global warming science? Real-world data underlying and supporting theory? We have both historical data (including ice cores going back now nearly a million years) and detailed recent data demonstrating correlations between CO2 (and other green house gases) and temperature, as well as demonstrating that the accumulation of CO2 (and other greenhouse gases) in the atmosphere in the industrial era has been far greater and far faster than in pre-industrial times. Falsifiable predictions? That's what models like CCSM3 are all about.

If I express frustration with and dismissal of those who actively deny the reality of global warming-induced climate change, it's because those who argue that it's real have done their homework, and the majority of those denying it simply haven't (and don't seem to have interest in doing so).

RB, I didn't go into details about the range of scenarios because I expected interested readers to actually go read the documents themselves. You'll be relieved to know that, while CO2 was highlighted in my write-up, the atmospheric models in the CCSM3 do in fact take into account other atmospheric components. The reason that CO2 is the favorite greenhouse gas of "political activists" is because it's both the one increasing in concentration in the atmosphere due to human activities and one that has a pretty significant effect in terms of heat-trapping.

Jason, as I mention above, the climatological science underlying global warming analysis is more than "best guess;" there are, unfortunately, organizations out there which are doing their level best to make you (and others) think that the science is more doubtful than it is.

As for Kyoto, it's useful to bear in mind that the predictions of a crippled economy arising from adherence to the protocols come from economists who, as a profession, tend to be far less accurate in their predictions than your local weather forecaster. Given a choice between the predictions of climatologists and the predictions of economists, where would you place your bet? And there's a good argument that acting to reduce carbon output would be an overall economic boost. If you read through the archives here at WC, you can find numerous examples of the innovation required for shifting away from a carbon-intensive economy resulting in improved efficiency and, ultimately, more wealth, not less.

As for the global warming problem itself, we at WC agree with you -- we can certainly fix it. But it will take time (and the longer we take, the worse the problem gets), effort (and a lot of it), innovation (ditto), and a willingness to embrace some pretty big changes (even those which might, in the short run, cost some money).

Mr Sensitive, the experiment results are described as modeling a 1% increase per year, making the doubling a 100 year event. The goal wasn't modeling the process of accumulation so much as the results. As for what it includes, you might have missed the page where they give an overview of what the model includes:


New treatments of cloud and ice-phase processes;
Improved representation of the interactions among water vapor, solar radiation, and terrestrial thermal radiation;
New treatment of the effects of aerosols, including prognostic sulfate, on the reflection and absorption of solar radiation; and
New dynamical frameworks suitable for modeling atmospheric chemistry.

"Slimedog," I have to admit I'm baffled by the "suddenly doubled" reference in the press release, since the actual experiments use a 1% increment capped at 2x (in one set of runs) and 4x (in another).


Thanks for pointing out the links to the news release and docs. I missed them the first time through.

I understand that climate is a non-linear phenomenon, making accurate modeling nearly impossible. At least they are trying.

After reading the release and the docs I am profoundly disappointed. The new model seems to be just more of the same. Quantitative improvements without significant qualitative improvements to the model. Bigger and faster but not smarter.

All of the models make predictions which contradict the satellite readings. None of them so far seem able to deal with the problem of clouds and how they can disrupt a nice neat model. Until the models become "smart enough" to deal with clouds intelligently, they will deserve whatever ridicule they may receive from the more rigorous sciences.

RB, if by satellite readings you mean the upper atmosphere temperature discrepancy, you may have missed this Nature article from early last month:


While not yet definitive, it significantly weakens the "satellite readings don't match" dismissal.

Climate is a non-linear phenomenon, and I am certain that we'll find more detailed readings and more sophisticated modeling that will alter some of the climatologists conclusions. You should be clear that this does not mean that those alterations will necessarily be for the better (the "abrupt climate change" theory is one non-linear result which is well-grounded in ice core data but incompletely understood). Regardless, the facts at this point -- the low-atmosphere temperature readings, the CO2 levels (among other greenhouse gases), the ice core data, the ocean data, and on and on -- are consistent and very, very troubling. Global warming is happening, human activities are the key component, the climate effects are highly likely to be very disruptive, and (most importantly) we can do something about it. We've gone to war based on information with far less certainty.


Climate science is still infantile. Only a few decades ago, the best climatologists were predicting a new ice age.

You should not expect the models as they gain in sophistication to support your present view. That would be foolish. We will all learn together, with an open mind, without the preconceptions that make current efforts so skewed.

Thanks for pointing out the nature article. It is a nice attempt, but not nearly enough to explain the discrepancy really, is it? Christy's criticism is exactly to the point.

(I'm a climatologist by training, and have worked on global climate models for about 13 years. So I thought I should weigh in here.)

The basic idea of global warming is grounded in the laws of physics. Period. If you add greenhouse gases to the atmosphere, they *will* trap heat. There is absolutely no way around that. The "greenhouse skeptics" don't really want to talk about that, but this has been known for over a hundred years.

The remaining scientific question is what this extra heat will do to the climatic patterns of the planet. Will it simply get warmer everywhere, all the time? Or will the fundamental weather patterns change? What will happen to the place you live, in terms of temperature, precipitation and other things?

Those are still open questions. The current generation of climate models are definitely getting better, but are still a ways off from giving these exact details. The only thing we can be absolutely sure of is that our climate *will* change. You would have to violate the laws of physics to have it any other way.

However, let's not confuse a scientific debate with a policy one.

We already have far better information on global warming (with explicit, physically-based models that can be tested against nature by anyone in the world) than we do on most topics. Do you want to compare the rigor and transparency of these models to economic forecasts (ha!), or the "models" used in our foreign policy (i.e., Dick Cheney's head)? Or what about the decisions you make about your health and diet? Is that science "perfect", or is it also an evolving body of knowledge? Should we wait on every possible decision until the science is flawless? Good luck -- because science, by definition, never gives a final answer.

While climate science has a ways to go, it is time to recognize that we should be having a policy debate -- not just a science one.

What do we do, given that we have a pretty good (but not absolutely perfect) idea that greenhouse emissions will dramatically change our climate? Do we *want* that? Do we believe the fossil fuel folks when they claim that reducing energy use will somehow "hurt" us?

Why wouldn't using less energy be a good thing? We save money, reduce imports from repressive regimes, reduce air pollution, save on health care costs, and prolong our limited supply of fossil fuels. And, hey, as a bonus, we might reduce the effects of global warming. Sounds like a good deal to me!

Thanks, Jon, great comment.


Jon, that is interesting, but it doesn't really help solve the impasse. Of course climate will change, regardless of what humans choose to do. Climate has always changed in the past and it will certainly change in the future. The record we have of climate is one of change.

There are many pieces of the climate puzzle that have not been assembled. Climatology is an infant science, and although it likes to dress itself in makeup and high heels and pretend to be grown up, it really isn't.

In ten or twenty years, we will have better models and better data. We will have better ways of figuring the effects of water vapor and clouds, and hopefully take a more realistic approach to the function of solar input.


The kyoto accord had some fatal flaws in it.

1 It put heavy burden on the one country least likely to suffer badly from global warming.

2 It didnt actauly control pollution it just moves it around because it lets too many go on polluting as much as they wana.

3 Its all based on models that cant predict how long we have and thus realy how much time we can take to swap over to something other then oil.

I would say what is going on is very simple. Because america has less to worry about global warming wise it has longer to deal with it and can take the time to switch to hydrogen without messing up the econ so much. And because the kyoto accord had no chance in hell of actauly working we didnt bother to listen and wont.

Steve in Houston:

"Why wouldn't using less energy be a good thing? We save money, reduce imports from repressive regimes, reduce air pollution, save on health care costs, and prolong our limited supply of fossil fuels. And, hey, as a bonus, we might reduce the effects of global warming. Sounds like a good deal to me!"

This sounds good, but it's taking a global phenomenon - warming - and putting all the onus locally, i.e., the United States.

It ignores the fact that the US is actually pretty efficient in its energy use, especially when you compare it to (as mentioned above) China and India. Will those countries voluntarily agree to curb their emissions as their economies transform? If not, what do we do about it?

China and India might not use as much oil as we do right now, but that's because they're still deriving a lot of their power from sources like coal, wood, and in some cases, animal dung. As their standards of living improve, they too will start demanding goods that need a more efficient power system.

A true alternative to the power efficiencies we get from oil and natural gas is a long way off in practical terms. Any attempt at a forced changeover to hugely inefficient solar/wind/geothermic right now would be a disaster for our economy and way of life - our food creation and delivery, our transportation, our communications, our technology industries all depend on a constant, cheap and reliable source of energy, none of which can be provided right now by clean technologies. It's not a science problem, it's an engineering problem.

There are a couple of things we could do as a nation to improve our efficiency right now without putting undue burdens on consumption. The first would be to build new power plants/refineries and improve the current ones to take advantage of technological advancements since the last new plant was built in the '70s. A concurrent boost in R&D on how to make these plants even more efficient and cleaner would be nice too.

If divorcing ourselves from foreign oil sources is a goal, then we should open ANWR up for drilling and increase our efforts for exploration. Of course, this wouldn't address the issue of other huge economies in the world - Japan, Korea, China, India, Europe - having at least as much dependence on Middle East oil as we do.

We could also invest more in nuclear power.

At the moment, of course, none of those alternatives are viable due to environmental dogma and the NIMBY syndrome. Hell, when you get down to it, the respectably Green residents of Nantucket are trying to block installation of wind turbines because they marred their view of the water.

The environmentalist industry has effectively blocked short- and mid-term solutions, which could buy us some time as we search for the next power revolution.


I supposed I care more about this issue because a friend of mine was involved in this issue directly.

His father owned a plant making fairly noxious gunk needed for some boring indutrial use. They were steadily pushed out of profitablity by new er and newer enviro laws until one day his father up and moved the company somewhere hellish and icky. The last word I heard from him was how over there they used methods even his father didnt like wich produced hiddious waste products and was fairly ineffienct not to mention dangerous. His father has wanted automatic controls but local officials had wanted more workers employed at pittance wages so manual controls were all over the place... His father made a great deal of money retired not long after and they sold that plant.. Dont remember when that was but I do remember the fact that plant polluted more in one year then the one in america had done in all the time it had operated. And that the environmentalists were soo proud of shutting the old plant down and of "saving" the earth.


Hi, Jon and anyone interested:

I'm a sf writer interested in climate change modelling and wonder if you know anything about the complexity and computing power involved in some of climate models. I need some advice from someone in the 'know' about climate modelling for a story I'm writing.

Please respond in private if you can offer some advice to sel@sasktel.net



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