 There are some certainties and many unknowns when it comes to climate change. We know that CO2 is a powerful greenhouse gas, that we are pumping huge quantities of it into the atmosphere, and that this is pushing up temperatures. Of all the uncertainties, however, perhaps the most alarming is what may become of the vast stores of methane under the arctic.  For many thousands of years, such methane - many times more warming than CO2 - has been trapped by the ice. as temperatures rise, it is starting to seep out, raising fears of a sudden, catastrophic release of methane into the atmosphere, massively accelerating climate change.  It may be a low-risk possibility, but it would certainly be a high-impact event. We must start exploring all possible solutions now. By the time the methane "time bomb" starts ticking, it will be too late.