Global warming could lead to release of more methane from seafloor

A warming ocean could release more of the potent greenhouse gas methane in a vicious cycle that leads to more warming, says a new report in the Proceedings of the National Academy of Sciences. Petroleum and methane seep consistently from small cracks in the seafloor, but a study of ocean sediments near Santa Barbara, Calif., found that during the last two major warming periods, around 11,000 and 15,000 years ago, three times more oil and methane were released than average. The researchers hypothesize that undersea methane ice melt could disturb the seafloor and open new cracks for seepage. “This is a source of methane that we might have assumed in the past was stable,” said lead author Tessa Hill. “As it turns out, it’s very sensitive to climate change.” Hill cautioned that the research should not be extrapolated worldwide, as methane stores in different parts of the ocean might not follow the same pattern. Small consolation, that.