Nature: Deposits of methane trapped in the sea floor could greatly increase the effects of global warming if released through drilling or natural processes. A newly discovered deposit of methane hydrate off the coast of Canada is the shallowest such deposit found to date, at just 290 m below sea level. Above 270 m, gas hydrates—crystalline solids of gas trapped in ice—are unstable. Because the deposit is so close to the boundary level, any warming in the water above the sea floor could cause the crystalline ice formation to melt and release the trapped methane. The newly discovered deposit is relatively small, says Charles Paull of the Monterey Bay Aquarium Research Institute in California, so its release would not have a significant impact on climate. However, the shallowness of the methane provides researchers an opportunity to study the nature of such deposits and the events that occur as they decompose.