Greenhouse gas (methane) leaking from Arctic Ocean floor

[OKIsItJustMe]

http://pubs.acs.org/doi/full/10.1021/es9026387

Greenhouse gas leaking from Arctic Ocean floor

Noreen Parks
Environ. Sci. Technol., Article ASAP
DOI: 10.1021/es9026387
Publication Date (Web): September 16, 2009
Copyright © 2009 American Chemical Society

Scientists have http://www.agu.org/pubs/crossref/2009/2009GL039191.shtml">reported the presence of previously unknown sources of methane—a greenhouse gas some 25 times more powerful than CO2 at trapping heat—bubbling up from the Arctic Ocean seafloor north of Norway. Gradual warming of a regional current has caused temperature-sensitive methane hydrate below the seabed to break down and discharge the gas, the researchers say.

For years, scientists have debated whether the planet’s rising temperatures would turn methane deposits in permafrost regions into a “ticking bomb” that, once detonated, could liberate vast quantities of methane to the atmosphere, possibly triggering disastrous climate-feedback effects. Some paleoclimate studies have argued that such scenarios have occurred in the past, and that the processes of hydrate formation and disintegration have been a primary driver of glacial cycles.

Over the past couple of decades, as the tools for oceanographic exploration have grown more sophisticated, researchers have documented about 90 oceanic locations of http://en.wikipedia.org/wiki/Methane_hydrate">methane hydrate, estimated to contain as much as 63,000 gigatons or more of carbon. Previously, International Polar Year (2007) surveys of the East Siberian Arctic shelf http://www.iarc.uaf.edu/highlights/2008/ISSS-08/">uncovered abundant methane seeps and measured record-breaking summertime concentrations of the gas in northern polar waters.

Hydrate usually forms in sediment beneath the seabed and is stable at depths below 300−500 meters (m), depending upon temperature, pressure, salinity, and the types of gases present, according to Graham Westbrook of the University of Birmingham (U.K.). However, on a research cruise in 2008, Westbrook and colleagues collected sonar images of more than 250 plumes of methane gas rising from the seafloor at depths ranging between 150 and 400 m. They found these plumes along a section of continental margin washed by the West Spitsbergen Current (WSC), an arm of the Gulf Stream that delivers Atlantic seawater to the Arctic. As the WSC has warmed by 1 °C over the past 30 years, the depth at which hydrate in the area is stable has fallen from 360 to 396 m, liberating methane, Westbrook says.

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See also:
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=207932&mesg_id=207932
http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=208901&mesg_id=208901

[villager]

1. well, that's going to trump pretty much all other issues...

n/t

[Richard D]

2. Positive feedback cycle

Translates to we're on our way to being toast.

[lapfog_1]

3. Sorry, it's Game Over.

Once the methane hydrates start dissolving, there is literally almost nothing we can do to fix this. The Global Warming positive feedback mechanisms will start dominating the contribution to green house gasses. We could turn off every power plant and park every vehicle and it still might not matter.

Better start seriously looking into those mega climate engineering projects (make our own "volcanoes" and throw millions of tons of dust into the upper atmosphere, etc.

[kestrel91316]

4. See there? This proves it's all a natural cycle and man has nothing

whatsoever to do with global warming.

:sarcasm:

Oh, and BTW: don't buy a big bag of people food.

[jimlup]

5. Well the deniers will be right about one thing...

the models will be way wrong - UNDERESTIMATES in the extreme.

[joshcryer]

6. IPCC is *epicly* conservative. It basically takes the lowest of the lowest estimates...

...and then IPCC AR4 actually didn't have ice melt data in it because the submission deadline ended before it could be included.

[OKIsItJustMe]

9. I hadn't understood it to be a problem with a deadline

http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html

Environ. Res. Lett. 2 (April-June 2007) 024002
doi:10.1088/1748-9326/2/2/024002

Scientific reticence and sea level rise

J E Hansen

NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA

Email: [e-mail]

Received 23 March 2007
Accepted 3 May 2007
Published 24 May 2007

…

The http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html#erl246875bib23">IPCC (2007) midrange projection for sea level rise this century is 20–43 cm (8–17 inches) and its full range is 18–59 cm (7–23 inches). The IPCC notes that they are unable to evaluate possible dynamical responses of the ice sheets, and thus do not include any possible `rapid dynamical changes in ice flow'. Yet the provision of such specific numbers for sea level rise encourages a predictable public response that the projected sea level change is moderate, and smaller than in http://www.iop.org/EJ/article/1748-9326/2/2/024002/erl7_2_024002.html#erl246875bib22">IPCC (2001). Indeed, there have been numerous media reports of `reduced' sea level rise predictions, and commentators have denigrated suggestions that business-as-usual greenhouse gas emissions may cause a sea level rise of the order of meters.

However, if these IPCC projected rates of sea level rise are taken as predictions of actual sea level rise, as they have been by the public, they suggest that the ice sheets can miraculously survive a BAU climate forcing assault for a period of the order of a millennium or longer. This is not entirely a figment of the IPCC decision to provide specific numbers for only a portion of the problem, while demurring from any quantitative statement about the most important (dynamical) portion of the problem. Undoubtedly there are glaciologists who anticipate such long response times, because their existing ice sheet models have been designed to match paleoclimate changes, which occur on millennial timescales.

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[WVRICK13]

7. Worse Than Greenhouse Gas

it is explosive and deadly to inhale in higher concentrations. I feel sorry for people in their 20s and younger. They are not going to have anything resembling a normal life.

[IDemo]

8. We're toast. Literally.