A major new study published in Reviews of Geophysics^* in December 2010 puts the spotlight on methane emissions from natural sources and asks the question, how might they both affect and be affected by future climate change.

Arctic and Antarctic ice cores provide a rich source of evidence that both temperature and atmospheric concentrations of methane and carbon dioxide have fluctuated over the past 800,000 years. These studies have also shown that the fluctuations are cyclic, and that higher temperatures are generally associated with higher levels of methane and carbon dioxide in the atmosphere.

Arctic and Antarctic ice cores provide a rich source of evidence that both temperature and atmospheric concentrations of methane and carbon dioxide have fluctuated over the past 800,000 years. These studies have also shown that the fluctuations are cyclic, and that higher temperatures are generally associated with higher levels of methane and carbon dioxide in the atmosphere.

Words Anna Pigott, image by 'Flora Cyclam' The submarine gas hydrate stability zone (GHSZ) of the West Spitsbergen continental margin appears to be contracting in response to a 1 deg C temperature rise of the West Spitsbergen ocean current – potentially releasing ~20 Tg yr-1 of methane into sea water.