New computer model advances climate change research

Aug 18, 2010
This image, taken from a larger simulation of 20th century climate, depicts several aspects of Earth’s climate system. Sea surface temperatures and sea ice concentrations are shown by the two color scales. The figure also captures sea level pressure and low-level winds, including warmer air moving north on the eastern side of low-pressure regions and colder air moving south on the western side of the lows. Such simulations, produced by the NCAR-based Community Climate System Model, can also depict additional features of the climate system, such as precipitation. Companion software, recently released as the Community Earth System Model, will enable scientists to study the climate system in even greater complexity. Credit: ©UCAR

Scientists can now study climate change in far more detail with powerful new computer software released by the National Center for Atmospheric Research (NCAR).

The Community Earth System Model (CESM) will be one of the primary used for the next assessment by the Intergovernmental Panel on (IPCC). The CESM is the latest in a series of NCAR-based global models developed over the last 30 years. The models are jointly supported by the Department of Energy (DOE) and the National Science Foundation, which is NCAR's sponsor.

Scientists and engineers at NCAR, DOE laboratories, and several universities developed the CESM.

The new model's advanced capabilities will help scientists shed light on some of the critical mysteries of global warming, including:

  • What impact will warming temperatures have on the massive ice sheets in Greenland and Antarctica?
  • How will patterns in the ocean and atmosphere affect regional climate in coming decades?
  • How will climate change influence the severity and frequency of , including hurricanes?
  • What are the effects of tiny airborne particles, known as , on clouds and temperatures?
The CESM is one of about a dozen climate models worldwide that can be used to simulate the many components of Earth's , including the oceans, atmosphere, , and land cover. The CESM and its predecessors are unique among these models in that they were developed by a broad community of scientists. The model is freely available to researchers worldwide.

"With the Community Earth System Model, we can pursue scientific questions that we could not address previously," says NCAR scientist James Hurrell, chair of the scientific steering committee that developed the model. "Thanks to its improved physics and expanded biogeochemistry, it gives us a better representation of the real world."

Scientists rely on computer models to better understand Earth's climate system because they cannot conduct large-scale experiments on the atmosphere itself. Climate models, like weather models, rely on a three-dimensional mesh that reaches high into the atmosphere and into the oceans. At regularly spaced intervals, or grid points, the models use laws of physics to compute atmospheric and environmental variables, simulating the exchanges among gases, particles, and energy across the atmosphere.

Because climate models cover far longer periods than weather models, they cannot include as much detail. Thus, climate projections appear on regional to global scales rather than local scales. This approach enables researchers to simulate global climate over years, decades, or millennia. To verify a model's accuracy, scientists typically simulate past conditions and then compare the model results to actual observations.

A broader view of our climate system

The CESM builds on the Community Climate System Model, which NCAR scientists and collaborators have regularly updated since first developing it more than a decade ago. The new model enables scientists to gain a broader picture of Earth's climate system by incorporating more influences. Using the CESM, researchers can now simulate the interaction of marine ecosystems with greenhouse gases; the climatic influence of ozone, dust, and other atmospheric chemicals; the cycling of carbon through the atmosphere, oceans, and land surfaces; and the influence of greenhouse gases on the upper atmosphere.

In addition, an entirely new representation of atmospheric processes in the CESM will allow researchers to pursue a much wider variety of applications, including studies of air quality and biogeochemical feedback mechanisms.

Scientists have begun using both the CESM and the Community Climate System Model for an ambitious set of climate experiments to be featured in the next IPCC assessment reports, scheduled for release during 2013-14. Most of the simulations in support of that assessment are scheduled to be completed and publicly released beginning in late 2010, so that the broader research community can complete its analyses in time for inclusion in the assessment. The new IPCC report will include information on regional climate change in coming decades.

Using the CESM, Hurrell and other scientists hope to learn more about ocean-atmosphere patterns such as the North Atlantic Oscillation and the Pacific Decadal Oscillation, which affect sea surface temperatures as well as atmospheric conditions. Such knowledge, Hurrell says, can eventually lead to forecasts spanning several years of potential weather impacts, such as a particular region facing a high probability of drought, or another region likely facing several years of cold and wet conditions.

"Decision makers in diverse arenas need to know the extent to which the climate events they see are the product of natural variability, and hence can be expected to reverse at some point, or are the result of potentially irreversible, human-influenced climate change," Hurrell says. "CESM will be a major tool to address such questions."

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thermodynamics
4.5 / 5 (8) Aug 18, 2010
I can already hear the shrill screech of the deniers who will come back with their Luddite view of simulations and rant about the funding going to these conspiracy participants. Let me pop out my denier model and make my prediction:

1) Liars built the model so it cannot be trusted.

2) They have warped the code so it will spit out flawed information that will increase their funding.

3) The Earth is cooling and the whole idea of warming is a fraud perpetrated by the "Warmists."

4) Warmer weather with more CO2 is good for the planet.

I'm sure I have missed some and they may even come up with something new, but you get the idea.

As a comment on the article, I am impressed with the effort that is being put into the models to improve them. I particularly like the inclusion of ice and particulate matter. I also like the idea of opening the data for others to look at years before inclusion in the IPCC publication. It amazes me that the deniers will be screaming about it.
TegiriNenashi
1 / 5 (6) Aug 18, 2010
So it is not warming that you are afraid of but critique?
Cheerio
5 / 5 (5) Aug 18, 2010
You gleaned 'fear' from that statement?
Brad_Hobbs
1 / 5 (6) Aug 18, 2010
Pejorative name calling aside, let me help you with those 'predictions'

1) The models were constructed by humans, and may contain human error.

2) The code should be open for examination, to verify it produces as accurate a result as possible with available data

3) Earth's climatic rhythms have been demonstrably misrepresented on several occasions, sometimes for agendas other than the best interests of the planet or life upon it

4) Is the closest to possibly true among the 'predictions', as both aggregate temperature averages and the partial pressure of atmospheric CO2 appear to be recovering from unusually low levels over the past several hundred years, and not at unprecedented rates.

It is a good thing that the modeling is being improved, as some of the previous versions used left a lot to be desired. Open, and transparent data will actually dispel the 'screaming', as the lack of transparency was the problem.
jsa09
3.7 / 5 (3) Aug 18, 2010
I am glad the model takes into account particulate matter in the atmosphere which has already had far greater impact on the global climate than global warming has.

Now if the model also accounts for cloud cover and cloud reflectivity it will actually produce some interesting results.

Studies done just on cloud cover alone estimate that man made clouds account for a degree or two of man made cooling. This is just the clouds made by aircraft.

Add in clouds made from pollution and we have a more significant and and serious problem. Much of the droughts and floods we have suffered over the last 30 years were probably caused by global dimming along with reduced precipitation on all the alps could well explain a great deal of the reduced glaciers.

Take all that into account then add in any global warming and see what we get.
bottomlesssoul
1 / 5 (3) Aug 19, 2010
Every new model is a gift to humanity, one day maybe even one will be right.

It is disconcerting that together the combined models give very different predictions about the future while all agreeing it's getting warmer and part of it's driven by humans.

I think we should reconsider the whole "let's remodel the atmosphere so I can get some chips from 7-11" strategy before we have better workable models.
gunslingor1
5 / 5 (2) Aug 19, 2010
Great job guys, especially thermo! Now your getting the idea... how to fight ignorance... beat them to their own uninformed arguement and clearly explain why they are full of Bull $hit.

Let me add a few to this:

1. Space umbrellas are the most reasonable solution if there every is a problem, far more reasonable than putting Co2 analyzers on stacks.
http://www.physor...846.html

Of course, you are all right, you've come up with their exact standard arguements. Of course, if the model predicts that GW is completely false (lol... good luck with that) they will not be making those arguements, even though they would still be relevant.

This model, to me, looks very sophisticated... I think it will be an extremely valueable asset. GOOD WORK GUYS!

TegiriNenashi
1 / 5 (2) Aug 19, 2010
I'm amused how easy you folks are on compliments. How often you witness somebody pulling off a mediocre effort and then hear "Good job, Mike"! The hard work in science is *assumed*. PhD students work their a**es to get degree. Not tenured professors have to jump a lot of hoopla before getting job security.

Researchers are supposed to refine their theories -- that is part of their job *responsibilities*. If a theory is not mature is is *openly* acknowledged by scientists. String theory, for example, didn't do any prediction confirmed by experiment and is subject of critique. Its advocates point to aesthetic qualities; how elegant it is. Compare it to AGW, which doesn't have either quality.
marjon
1 / 5 (2) Aug 19, 2010
GIGO.
How is CLARREO coming along?
Open, and transparent data will actually dispel the 'screaming', as the lack of transparency was the problem.

Why wasn't this the policy from the beginning?
The community has much work to do before earning trust after 30+ years of mis-trust.
marjon
1 / 5 (2) Aug 19, 2010
To paraphrase CS Lewis:
"We must give full weight to the claim that nothing but science, and science globally applied, and therefore unprecedented Government controls, can"...save the earth from AGW. Remainder of original quote: ..." produce full bellies and medical care for the whole human race: nothing, in short, but a world Welfare State. "

http://www.indepe...p?p=7496
Scientists, stick to science.
John_balls
5 / 5 (3) Aug 21, 2010
To paraphrase CS Lewis:
"We must give full weight to the claim that nothing but science, and science globally applied, and therefore unprecedented Government controls, can"...save the earth from AGW. Remainder of original quote: ..." produce full bellies and medical care for the whole human race: nothing, in short, but a world Welfare State. "

http://www.indepe...p?p=7496
Scientists, stick to science.

What insane asylum do you post from. Surely they need to up your meds.
marjon
1 / 5 (2) Aug 22, 2010
To paraphrase CS Lewis:
"We must give full weight to the claim that nothing but science, and science globally applied, and therefore unprecedented Government controls, can"...save the earth from AGW. Remainder of original quote: ..." produce full bellies and medical care for the whole human race: nothing, in short, but a world Welfare State. "

http://www.indepe...p?p=7496
Scientists, stick to science.

What insane asylum do you post from. Surely they need to up your meds.

Wow, another 'rational' response!