Slip of the tundra

CO2 released from disappearing permafrost must be factored into climate projections

Posted by Joseph Romm (Guest Contributor) at 2:01 PM on 23 May 2008

Read more about: climate | climate science | climate change impacts | Arctic | greenhouse-gas emissions

What is the point of no return for the climate -- the level of CO2 concentrations beyond which catastrophic outcomes are virtually unstoppable?

No one knows for sure, but my vote goes for the point at which we start to lose a substantial fraction of the tundra's carbon to the atmosphere -- substantial being 0.1 percent per year! As we saw in my last post, frozen away in the permafrost is more carbon than the atmosphere currently contains (and much of that is in the form of methane, a far more potent greenhouse gas than carbon dioxide).

What is the point of no return for the tundra? A major 2005 study ($ub. req'd) led by NCAR climate researcher David Lawrence found that virtually the entire top 11 feet of permafrost around the globe could disappear by the end of this century.

Using the first "fully interactive climate system model" applied to study permafrost, the researchers found that if we tried to stabilize CO2 concentrations in the air at 550 ppm, permafrost would plummet from over 4 million square miles today to 1.5 million. If concentrations hit 690 ppm, permafrost would shrink to just 800,000 square miles.

While these projections were done with one of the world's most sophisticated climate system models, the calculations do not include the feedback effect of the released carbon from the permafrost. That is to say, the CO2 concentrations in the model rise only as a result of direct emissions from humans, with no extra emissions counted from soils or tundra. Thus, they are conservative numbers -- or overestimates -- of how much CO2 concentrations have to rise to trigger irreversible melting.

In short, those would-be points of atmospheric stabilization, 550 ppm or 690 ppm, aren't stable at all -- they are past the point of no return. We must stay well below 450 ppm to save the tundra and hence the climate.

Significantly, none of the major climate models -- including NCAR's (!) -- included this crucial tundra feedback in their forecast of future concentrations atmospheric impacts for the IPCC. Thus, the 2007 Fourth Assessment Report by the U.N.'s Intergovernmental Panel on Climate Change underestimates greenhouse gas forcings and climate change this century -- an especially worrisome situation given that the 2007 IPCC report was already incredibly dire.

Yet the IPCC report says that to stabilize below 450 ppm, the world must average under 5 billion tons of carbon emissions a year for the whole century. Annual carbon emissions are currently over 8 billion tons and rising 3 percent per year. We need to cut that to 4 billion by 2050 and below 1 by 2100.

And remember the tundra has some 1,000 billion metric tons of carbon. In the future, losing a mere 0.2 percent per year of the tundra (in the form of CO2) would add two billion tons a year to our carbon emissions, yet that rate would still leave us with over 80 percent of the tundra by 2100, so it is not an especially fast loss rate compared to what we may see at 550 ppm or higher. And, of course, the greenhouse gas impact would be far greater if much of that carbon were released as methane.

The point is that once even a small fraction of the tundra begins to defrost, it makes efforts to stabilize anywhere near 450 ppm almost impossible. But again, should we get to 550 ppm or above for any length of time, then permafrost emissions (and other amplifying feedbacks) are likely to take us to 700 to 1,000 ppm and beyond, which is the end of life on this planet as homo sapiens have come to know it.

So, the only prudent option is to stay below 450 ppm, which is eminently doable from a technological and economic, though not (yet) political, perspective.

My next post will explore some recent research on destructive feedbacks that are internal to the tundra ecosystem.

This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.

For story: Slip of the tundra
4 Comments | Post a Comment

Basic math?

"While these projections were done with one of the world's most sophisticated climate system models, the calculations do not include the feedback effect of the released carbon from the permafrost."

Evidently it is too much to expect, that scientists remember their basic math education and take it into account in climate modeling.

The only explanation I can think of is that politics must be effecting studies like this. Climate scientists MUST understand feedback effects and exponential change.

How do they graduate and suceed in academia without that kind of understanding? Mind boggling.

So how do we fight the extra powerful feedback effect of GHGs like methane and nitrous oxide? By curtailing their emissions where we can. From the waste stream.

If 5% of our energy use was provoded by biogas, it would offset the rest of our GHG footprint and halt climate change. And that would stop tundra, methane hydrate sea floor ice, and glacier and ice cap melting. All exponential feedback climate changers.

We have to get a handle on the extra powerful GHGs we can control. Biodigestors powering up tractors,trucks, trains, and grid backup with methane could get us to 5% easily. And save oil and money. paying its own way while turning climate disaster around.

Organic fertilizer from the biodigestors would replace ammonia fertilizer, thus curtailing nitrous oxide emissions. This is a huge GHG effect. Up to 2/3 the carbon sequestered by crops is negated by the nitrous oxide emitted by the ammonia fertilizer.

Across all chemical ag that has a catastrophic GHG effect.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 7:59 AM on 24 May 2008

Public copy of 2005 paper and new one

The 2005 paper is here.

I also noticed this new one still in press. I haven't had a chance to read it, but likely it would worsen the picture.

Accelerated Arctic land warming and permafrost degradation during rapid sea ice loss

Abstract: Coupled climate models and recent observational evidence suggest that Arctic sea ice may undergo abrupt periods of loss within fifty years. Here, we evaluate the impact of rapid sea ice loss on terrestrial Arctic climate and ground thermal state in the Community Climate System Model. We find that western Arctic land warming trends during rapid sea ice loss are 3.5 times greater than secular 21st century climate-change trends outside these periods. The accelerated warming signal extends up to 1500km inland and is apparent throughout most of the year, peaking in autumn. Idealized experiments using the Community Land Model, with improved permafrost dynamics, indicate that an accelerated warming period substantially increases ground heat accumulation - the earlier the event the greater the long-term impact. For warm permafrost, enhanced heat accumulation can lead to rapid degradation. For colder ground, heat accumulation preconditions permafrost for earlier and/or more rapid degradation under continued warming.

by Steve Bloom at 2:56 PM on 24 May 2008

Units of measurement problem

Umm, I don't think CO2 is directly emitted by warming and rotting permafrost. Methane is. You can turn that into an equivalent mass of carbon or a greenhouse reactivity (e.g., 31 x) but it is NOT CO2 being emitted unless I am missing something.

I'd like to see some numbers about what those emission potentials for permafrost methane are, since it is my understanding that freshwater and coastal swamps are much more productive at bubbling up methane. I respect UCAR as an organization but tend to wonder, since I don't have an extra couple hundred to through down on such academic papers.

And one has to ask, since ordinary swamps are such heavy producers of methane, yet we drained millions and millions of acres of it, why the planet didn't "exponentially" turn stone cold as some kind of reverse "tipping point." Perhaps it is because the atmospheric half-life of methane is much shorter than that for CO2? -sam

Onward through the fog

by Sam Wells at 9:48 PM on 24 May 2008

Slip of the tundra

The magnitude of carbon emissions from tundra is also supported by the Russian Academy of Sciences in Environment New Service, 9/7/06, "Melting Russian Permafrost Could Accelarate Global Warming". The estimate there is that the thawing Siberian tundra alone could release some 500 billion tons of carbon. Citation in my book "Klima 2055". I would like to send Joseph Romm a copy if he would give me his address.

Dr. Lutz Peters lutzpeters@yahoo.com

by lutzpeters at 5:51 AM on 27 May 2008

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