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Tuesday, December 13, 2011

2011 AGU: Arctic Methane Workshop: An assessment of threats to Arctic and global warming; and an evaluation of techniques to counter these threats

TITLE: Arctic Methane Workshop: An assessment of threats to Arctic and global warming; and an evaluation of techniques to counter these threats


CURRENT SECTION/FOCUS GROUP: Global Environmental Change (GC)

CURRENT SESSION: GC27. Permafrost and Methane 4. Arctic Gas Hydrate Methane Release and Climate Change


INSTITUTIONS (ALL): 1. Cloudworld Ltd, London, United Kingdom.

ABSTRACT BODY: This is a report from a workshop especially convened in order to identify means to reduce the threat of methane being emitted from sources in the Arctic in such quantities as to have a major impact on global warming. Major factors in the assessment of this threat are the unexpectedly rapid retreat of sea ice [1] and the unexpectedly large quantities of carbon which might be emitted as methane [2]. The assessment takes into account the possibility of the Arctic Ocean becoming seasonably ice free this decade if there is no action to cool the Arctic.

The report includes the latest work from Natalia Shakhova, Igor Semiletov and others on East Siberian Arctic Shelf (ESAS) - particularly concerning the present large emissions of methane and the possibility of sudden release of much larger quantities. Large releases could also occur from Arctic lakes and wetlands, and this threat will also be assessed. Work by Isaksen and others suggests that if emissions are increased from present levels by a factor of 2 or more, then not only is the lifetime of methane in the atmosphere increased, thus increasing the methane�s global warming potential over time, but indirect radiative forcing is increased also [3]. If total methane emissions rise fivefold, as possible with a major discharge from ESAS, then the contribution to climate forcing, and hence global warming, could be greater than from the current level of atmospheric CO2.

What can be done quickly to reduce this methane threat? The workshop's evaluation of various techniques to deal with the methane will be presented. A three-prong attack is proposed:
1. cooling the Arctic, regionally or locally, using Solar Radiation Management (SRM-type geoengineering);
2. management of the methane environment at the local level (see below);
3. capture or destruction of methane, already in the atmosphere.

Local approaches can be categorised according to where the intervention action takes place. Where the methane is from lake or sea bed, the action could be:
- below the permafrost, where there may already be methane or methane hydrate;
- in the permafrost, or to plug gaps in the permafrost where methane is rising;
- in the bed of the sea or lake, above the permafrost layer;
- in the water at the bottom of the sea or lake;
- at the surface of the sea or lake, and below any ice;
- at the point of emergence of methane into the atmosphere.

An evaluation of a number of possible techniques for dealing with various situations will be presented. This evaluation considers the effectiveness of large-scale deployment of the techniques, used singly or in combination, to reduce the risk of a methane excursion causing abrupt climate change.!msg/geoengineering/zbmLVR5HHpM/SL926VzKWmYJ

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