New Study Shows Climate Change Largely Irreversible

[whitesoxfan101]

http://www.noaanews.noaa.gov/stories2009/2...26_climate.html

 

A new scientific study led by the National Oceanic and Atmospheric Administration reaches a powerful conclusion about the climate change caused by future increases of carbon dioxide: to a large extent, there’s no going back.

 

The pioneering study, led by NOAA senior scientist Susan Solomon, shows how changes in surface temperature, rainfall, and sea level are largely irreversible for more than 1,000 years after carbon dioxide (CO2) emissions are completely stopped. The findings appear during the week of January 26 in the Proceedings of the National Academy of Sciences.

 

“Our study convinced us that current choices regarding carbon dioxide emissions will have legacies that will irreversibly change the planet,” said Solomon, who is based at NOAA’s Earth System Research Laboratory in Boulder, Colo.

 

“It has long been known that some of the carbon dioxide emitted by human activities stays in the atmosphere for thousands of years,” Solomon said. “But the new study advances the understanding of how this affects the climate system.”

 

The study examines the consequences of allowing CO2 to build up to several different peak levels beyond present-day concentrations of 385 parts per million and then completely halting the emissions after the peak. The authors found that the scientific evidence is strong enough to quantify some irreversible climate impacts, including rainfall changes in certain key regions, and global sea level rise.

 

If CO2 is allowed to peak at 450-600 parts per million, the results would include persistent decreases in dry-season rainfall that are comparable to the 1930s North American Dust Bowl in zones including southern Europe, northern Africa, southwestern North America, southern Africa and western Australia.

 

The study notes that decreases in rainfall that last not just for a few decades but over centuries are expected to have a range of impacts that differ by region. Such regional impacts include decreasing human water supplies, increased fire frequency, ecosystem change and expanded deserts. Dry-season wheat and maize agriculture in regions of rain-fed farming, such as Africa, would also be affected.

 

Climate impacts were less severe at lower peak levels. But at all levels added carbon dioxide and its climate effects linger because of the ocean.

 

“In the long run, both carbon dioxide loss and heat transfer depend on the same physics of deep-ocean mixing. The two work against each other to keep temperatures almost constant for more than a thousand years, and that makes carbon dioxide unique among the major climate gases,” said Solomon.

 

The scientists emphasize that increases in CO2 that occur in this century “lock in” sea level rise that would slowly follow in the next 1,000 years. Considering just the expansion of warming ocean waters—without melting glaciers and polar ice sheets—the authors find that the irreversible global average sea level rise by the year 3000 would be at least 1.3–3.2 feet (0.4–1.0 meter) if CO2 peaks at 600 parts per million, and double that amount if CO2 peaks at 1,000 parts per million.

 

“Additional contributions to sea level rise from the melting of glaciers and polar ice sheets are too uncertain to quantify in the same way,” said Solomon. “They could be even larger but we just don’t have the same level of knowledge about those terms. We presented the minimum sea level rise that we can expect from well-understood physics, and we were surprised that it was so large.”

 

Rising sea levels would cause “…irreversible commitments to future changes in the geography of the Earth, since many coastal and island features would ultimately become submerged,” the authors write.

 

Geoengineering to remove carbon dioxide from the atmosphere was not considered in the study. “Ideas about taking the carbon dioxide away after the world puts it in have been proposed, but right now those are very speculative,” said Solomon.

 

The authors relied on measurements as well as many different models to support the understanding of their results. They focused on drying of particular regions and on thermal expansion of the ocean because observations suggest that humans are contributing to changes that have already been measured.

 

Besides Solomon, the study’s authors are Gian-Kasper Plattner and Reto Knutti of ETH Zurich, Switzerland, and Pierre Friedlingstein of Institut Pierre Simon Laplace, Gif-Sur-Yvette, France.

 

NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.

 

This article almost sounds like a case of using exaggerated scare tactics, but it appears they have science that causes them to believe it's actually true. Maybe all of the enviornmental arguments and healthier for the planet/"greener" ideas don't matter because it's too late anyways. That is a sad thought if true.

[NorthSideSox72]

http://www.noaanews.noaa.gov/stories2009/2...26_climate.html

 

This article almost sounds like a case of using exaggerated scare tactics, but it appears they have science that causes them to believe it's actually true. Maybe all of the enviornmental arguments and healthier for the planet/"greener" ideas don't matter because it's too late anyways. That is a sad thought if true.

All the more reason to stop the slide now.

 

And while the carbon level specifically may be difficult to reverse, that definitely does not mitigate the need for "green" ideas. Cutting pollution and increasing green space have huge positive effects, beyond just carbon emission levels.

 

[Steve9347]

This needs to stop now. All I can think of is the "radioactive Earth" in Asimov's Pebble in the Sky.

[Balta1701]

This article almost sounds like a case of using exaggerated scare tactics, but it appears they have science that causes them to believe it's actually true. Maybe all of the enviornmental arguments and healthier for the planet/"greener" ideas don't matter because it's too late anyways. That is a sad thought if true.

Actually, "too late anyways" is not what it says. The CO2 concentration given in that article is 450-600 PPM. We're currently approaching 400. What we've already done is bad enough, but every year that goes by gives you another 4-5 ppm or so, depending on the economies of the world and China's coal use. But what it does say is it is getting very very close to being too late, and we already going to see major shifts based on what we've already done.

[NorthSideSox72]

Actually, "too late anyways" is not what it says. The CO2 concentration given in that article is 450-600 PPM. We're currently approaching 400. What we've already done is bad enough, but every year that goes by gives you another 4-5 ppm or so, depending on the economies of the world and China's coal use. But what it does say is it is getting very very close to being too late, and we already going to see major shifts based on what we've already done.

And again, all the more reason to act swiftly now.

 

This is one of the problems I have with the stimulus bill. Yes, it includes some big money for alt energy. But it also includes big money for off-focus stuff, as you pointed out, like oil companies. The government needs to act smartly here - the great emphasis of any stiumulus package should be targeted on industries that are in the nation's best interests. Getting off oil should be priority number 1 on that list.

 

Further, what I have not yet seen in the stiumulus package or other legislation, is significant movement on the natural end of the environment equation - protection and promotion of open and green space. It can't just be about reducing pollution and emissions - it also needs to be adding more green matter to help make the air healthier. Forests are weakening because of the level of carbon in the atmosphere, which renders them less useful for scrubbing CO2 from the air (and in extreme cases, some stressed forests are actually carbon POSITIVE).

 

Mr. Obama - designate all proposed wilderness areas already under federal control as full wilderness, set aside monies for states and localities to protect and create more green space, and use the down real estate market to buy up land to take out of circulation. That last point can be done via private entities like The Nature Conservancy, or local/state agencies, not just the federal government. And it would have the nice side effect of helping bolster the real estate market a bit.

[whitesoxfan101]

I agree that action is needed right away, but that article is incredibly dire in it's portrayal of things. It was hard to read it and not feel like it was saying, to a certain degree, it's too late. I don't think it's too late, and I don't think science feels that way either, but that article sure seemed to be talking that way.

 

The sad part is that if it is indeed "very very close to being too late", I am not sure things can be fixed in time. Too many hurdles to clear worldwide in that regard in my opinion, even with a skilled orator like Obama running the free world.

Edited January 28, 2009 by whitesoxfan101

[Balta1701]

I agree that action is needed right away, but that article is incredibly dire in it's portrayal of things. It was hard to read it and not feel like it was saying, to a certain degree, it's too late. I don't think it's too late, and I don't think science feels that way either, but that article sure seemed to be talking that way.

 

The sad part is that if it is indeed "very very close to being too late", I am not sure things can be fixed in time. Too many hurdles to clear worldwide in that regard in my opinion, even with a skilled orator like Obama running the free world.

The latter part is probably true. There really isn't the political will to make things be fixed on time. We've demonstrated that.

 

You want to get it fixed on time? Commit to Al Gore's 100% renewable electricity by 2020 goal. If you can't do that, then you're probably too late, and you're going to suffer some major catastrophes. And that isn't even counting the ice sheets.

[NorthSideSox72]

The latter part is probably true. There really isn't the political will to make things be fixed on time. We've demonstrated that.

 

You want to get it fixed on time? Commit to Al Gore's 100% renewable electricity by 2020 goal. If you can't do that, then you're probably too late, and you're going to suffer some major catastrophes. And that isn't even counting the ice sheets.

The amazing thing about that goal? Last year sometime, someone published an article where they crunched the numbers, and found that if you have put the cost of the Iraq war (roughly $1T) into converting to renewable energy, we could have gotten so far with it that we would only need domestic oil. We'd be energy independent, and using 80% less fossil fuels.

 

Instead, we bought Iraq. Awesome.

[Balta1701]

One more critical point: it’s important that people not react to Solomon’s work with despair. Yes, a certain amount of climate change, due to past emissions, is inevitable, and will not be reversible. But it would be tragic if people concluded that therefore there is nothing we can do, that it is futile to reduce emissions, and that therefore all efforts should shift to adaptation. To the contrary: if nothing is done to cut emissions, and soon, the climate our children and grandchildren will face will almost certainly be far less hospitable, and there will be no turning back. By the time we know for certain how bad it will be it will be too late to take any corrective action. The Solomon paper should finally bury the idea that we can wait and see. It further strengthens the case for immediate, strong mitigation. The good news is that it’s getting cheaper every day to cut carbon emissions. Through learning, scale economies, R&D, and other forms of innovation, new technologies for carbon-neutral renewable energy are becoming more available and less expensive. Each megawatt of solar or wind capacity we build lowers the cost of the next and the next — a positive feedback we need to strengthen if we are too avoid irreversible harm to the ability of the planet to sustain us.

 

John Sterman

 

Jay W. Forrester Professor of Management

Director, MIT System Dynamics Group

MIT Sloan School of Management

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