Thanks to the Arctic Methane Emergency Group AMEG for this.

What is an Appropriate Response for the Arctic Methane Emergency?

A. Stabilize Arctic albedo - sea ice and snow How? Arctic cooling, stop black carbon emissions

B. Stabilize Arctic carbon How? Extensive methane monitoring (foremost and mainly methane)

How? Maximize methane sinks, reverse emissions

How? Reverse emissions, target zero carbon emissions, maximize carbon sinks, develop artificial carbon sinks, extract CO2 from air and secure (atmospheric CCS: carbon capture and storage)  

C. Stabilize global carbon — methane
 
  — CO2

1. First and foremost, the meltdown of the Arctic summer sea ice, with the Arctic already emitting additional methane to the atmosphere, must be declared a planetary emergency.

2. The immediate emergency response is to stabilize Arctic sea ice and Arctic carbon by cooling the Arctic. This is certainly doable and can be done safely.

3. We also have to immediately and drastically cut global CO2 and methane emissions, which can be done. The science is definite on the need to reach zero carbon emissions. We have to rapidly develop the capacity to extract CO2 directly from the air, which can be done by several methods, both biological and technological.

4. Black carbon soot drifts up to the Arctic settling on snow and reducing Arctic albedo. Stopping this emission would have an immediate cooling effect on the Arctic. Sources are burning fossil fuels and biomass.

5. To achieve these urgent goals, it is necessary (as has been urged by peace and social groups for many years) for the vast amounts of funds and human resources devoted to the military and aerospace industries to be diverted to the great enterprise of stabilizing the Arctic, protecting our planet, and rescuing our future.

6 There are, of course, also many personal lifestyle changes that will help reduce global carbon emissions and it is hoped that people will take advantage of them all when they become aware of the dire emergency we are now in.

7. The Arctic Methane Emergency Group is investigating all possible options for developing the capacity to safely cool the Arctic within a couple of years.

Notes on Geoengineering Requirements to Avert Catastrophic Global Warming from a Sudden Large Emission of Methane, Arctic Methane Emergency Group, December 2011:

Flux to be overcome to save the sea ice
• Arctic warming is much faster than global warming, by a factor of about 6 times, and the warming is accelerating, due to positive feedback.
• Warming is mostly driven by currents from the Atlantic and the loss of albedo effect.
• The extra heat flux, which is warming the Arctic with respect to its pre-industrial temperature, is currently of the order of one petawatt.
• September sea ice volume trend is to zero in 2014 or 2015, by which time the heat flux would be nearly double what it is at present.
• This could be a point of no return, when it becomes impossible to prevent further retreat of the sea ice, with accelerated Arctic warming causing ever larger methane emissions in a feedback loop until runaway global warming becomes inevitable.
• Geoengineering techniques for cooling the Arctic have to be applied by spring 2013 to reduce that risk as far as it is possible to do so.

Flux from a sudden large emission of methane
• Under shallow seas there is around 1000 Gt methane as methane hydrate and 700 Gt methane as free gas.
• Up to 50 Gt (3%) of this methane might be unexpectedly released, e.g., by an earthquake, thus increasing atmospheric concentration by up to 12 times.
• The global forcing from such a pulse could rise to around 9 watts/m² over the course of a single year and then fall only slowly.
• Such forcing could send global warming over 2 degrees C in a decade.
• The local forcing would also lead to further Arctic methane release in a positive feedback loop, with runaway global warming inevitable.
• Geoengineering techniques for cooling and for methane capture have to be applied as soon as possible to reduce the risk from unexpectedly large emissions of methane into the atmosphere.

Emergency intervention is needed both to save the Arctic sea ice and to reduce the risk of catastrophic global warming from a sudden large emission of methane.