The Climate in the Cryosphere

Subtitle: A Tragedy

Word from the U.S. Geological Survey? Arctic Now Traps 25 Percent of World’s Carbon — But That Could Change. And, not for the good either.

“Go on. I know that you want to use the Romm quote.”

All right, I will. “If we lose the tundra,” cautions Joseph Romm, “we loose a livable climate.”

“So, what is the Good News this go round, eh?”

I presume that you refer to the titles of previous AG posts?

“Yes, so what is it?”

800 million metric tons of CO2.

This figure shows the mean extent of permafrost in the Arctic, estimated for (a) the years 1990-2000 and (b) the years 2090-2100. In (c), the estimation of loss of permafrost by 2100 is overlaid on estimates for the year 2000. Credit: A. David McGuire, USGS

According to a study published in the November issue of Ecological Monographs, David McGuire and colleagues show how the Arctic has been a carbon sink since the end of the last Ice Age. On average, says McGuire, a member of the U.S. Geological Survey and faculty at the University of Alaska at Fairbanks, the Arctic accounts for 10-15 percent of the Earth’s carbon sink. But the rapid rate of climate change in the Arctic – about twice that of lower latitudes – could eliminate the sink and instead, possibly make the Arctic a source of carbon dioxide.

Carbon generally enters the oceans and land masses of the Arctic from the atmosphere and largely accumulates in permafrost, the frozen layer of soil underneath the land’s surface. Unlike active soils, permafrost does not decompose its carbon; thus, the carbon becomes trapped in the frozen soil. Cold conditions at the surface have also slowed the rate of organic matter decomposition, McGuire says, allowing Arctic carbon accumulation to exceed its release.

But recent warming trends could change this balance. Warmer temperatures can accelerate the rate of surface organic matter decomposition, releasing more carbon dioxide into the atmosphere. Of greater concern, says McGuire, is that the permafrost has begun to thaw, exposing previously frozen soil to decomposition and erosion. These changes could reverse the historical role of the Arctic as a sink for carbon dioxide.

“In the short term, warming temperatures could release more Arctic carbon to the atmosphere,” says McGuire. “And with permafrost thawing, there will be more available carbon to release.”

“So is that it?”

You are being quite stoic, perhaps a few more graphs might help impress you with the severity of the situation.

“The Arctic ice isn’t going to recover, and we are headed for ice free summers in the foreseeable future.”

“So is that it?”

Well, then there is the methane.

On the scale of a few decades, the thawing permafrost could also result in a more waterlogged Arctic, says McGuire, a situation that could encourage the activity of methane-producing organisms. Currently, the Arctic is a substantial source of methane to the atmosphere: as much as 50 million metric tons of methane are released per year, in comparison to the 400 million metric tons of carbon dioxide the Arctic stores yearly. But methane is a very potent greenhouse gas – about 23 times more effective at trapping heat than carbon dioxide on a 100-year time scale. If the release of Arctic methane accelerates, global warming could increase at much faster rates.

“400? I thought you stated 800?”

I did. 800 million metric tons. The range for the Arctic as a global carbon sink is between zero and 25 percent. So, 800 is an upper estimate.

“But zero? It could be zero?”

It is within the realm of possibility.

“Ah, hah!”

But, then, there is the methane.

“Ah, yes, the methane.”

“We don’t understand methane very well, and its releases to the atmosphere are more episodic than the exchanges of carbon dioxide with the atmosphere,” says McGuire. “It’s important to pay attention to methane dynamics because of methane’s substantial potential to accelerate global warming.”

Methane is increasing because the permafrost is melting. “The permafrost is melting fast all over the Arctic, lakes are forming everywhere and methane is bubbling up out of them,” attests Katey Walter.

“Doesn’t he conclude by stating ‘uncertainties still abound about the response of the Arctic system to climate change.’”

Yes. Thought you might focus on the “more study needed” statement. Did you read the commentary to the article warning that “Climate Meltdown” is happening way faster than previously thought? Especially the part about slipping back into comfortable denial.

“I forget.”

Hm. How about evidence that the amount of methane in the atmosphere is 155% more than in pre-industrial times?

“…”

To repeat, the clathrate already is hitting the fan, so to speak. It is time to buy a clue: it was Professor Romm in the library with an uncharacteristically blunt instrument.

To repeat, sooner than expected we are on our way to an ice-free Arctic Ocean in the summer. This is a very big tipping point.

Note: The article, Sensitivity of the Carbon Cycle in the Arctic to Climate Change, is on line in Ecological Monographs (Membership required or pay per view). The coordinating lead author is David McGuire, USGS, and the co-authors include internationally renowned scientists from Canada, Germany, Sweden, and the United States. This study was sponsored by the Arctic Monitoring and Assessment Program, the Climate in the Cryosphere Program, and the International Arctic Science Committee.

The Arctic Thaw Could Make Global Warming Worse (scientificamerican.com)

This entry was written by jcwinnie, posted on 2009-10-17 at 10:09 pm, filed under climate, denial, environment, investigation, patterns, thermodynamics and tagged climate, emissions, patterns, thermodynamics. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Both comments and trackbacks are currently closed.

3 Comments

jcwinnie

Posted 2009-10-19 at 9:45 am | Permalink

A review of 400 major climate studies published since the 2007 report of the Intergovernmental Panel on Climate Change (IPCC) says that the world is warming more rapidly than the panel’s mainstream projections and concludes that the rapid buildup of greenhouse gases “has most likely committed the world to a warming of 1.4 to 4.3 degrees C” — 2.5 to 7.7 degrees F — by 2100. The updated report, compiled by the United Nations Environmental Program, said events that the IPCC forecast would occur long-term are already occurring or on the verge of occurring. These include rapid acidification of the oceans, faster-than-expected melting of the Greenland and West Antarctic ice sheets, rising sea levels, shifting ocean and atmospheric currents, and warming polar land masses. “This compendium reminds us that the risks we face may be much greater than what’s generally represented in IPCC assessments,” said Ken Caldeira of Stanford University, one of roughly 60 scientific reviewers of the report. The report said that burgeoning economies in China, India, and other developing countries, coupled with a lack of emissions cutbacks in the industrialized world, have caused greenhouse gas emissions to grow more rapidly than the most extreme scenario presented by the IPCC.

World Changing
jcwinnie

Posted 2009-11-8 at 1:53 pm | Permalink

Photo: Michael Nolan
jcwinnie

Posted 2009-11-8 at 6:13 pm | Permalink

“I would argue that, from a practical perspective, we almost have a seasonally ice-free Arctic now, because multiyear sea ice is the barrier to the use and development of the Arctic,” said David Barber. Barber is Canada’s Research Chair in Arctic System Science at the University of Manitoba. This is strong evidence that the Arctic climate is passing another tipping point.

Joseph Romm explains about the implications to the cryosphere and life on the planet as we know it.

The multiyear ice covering the Arctic Ocean has effectively vanished…

The latest tracking of Arctic sea ice extent from the National Snow and Ice Data Center shows that we’ve hit the record low Arctic sea ice extent for this time of year. In a post last week, “Warm winds slow autumn ice growth,” NSIDC noted “October 2009 had the second-lowest ice extent for the month over the 1979 to 2009 period.”

As Reuters noted in their remarkable piece on Canadian cryosphere scientist David Barber, “Scientists link higher Arctic temperatures and melting sea ice to the greenhouse gas emissions blamed for global warming.”

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By Reasons for Concern about the 2 ºC Threshold – After Gutenberg on 2009-12-16 at 2:56 pm

[...] are above normal and rising, there is a correlation to rising surface temperatures, particularly in the polar regions. We are see changes in the atmosphere and ocean, and a reluctance by nations to curb emissions. [...]

After Gutenberg