Nature: Marine geologists studying the warm Gulf Stream current have noticed that it is shifting into areas previously dominated by colder temperatures. In a paper published in Nature, Matthew Hornbach and Benjamin Phrampus of Southern Methodist University in Dallas, Texas, discuss how the warmer water is triggering the breakdown of frozen methane hydrate along the continental slope of the eastern US; the breakdown could lead to underwater landslides and the release of methane, a greenhouse gas. According to their model, however, it will take some 5000 years of warmer water for all of the methane to sublimate. The area of real concern, according to Hornbach, is the Arctic, because it is undergoing the most rapid warming and hence the most dramatic loss of sea ice and changes in oceanographic conditions. The researchers are collaborating with the US Geological Survey to apply their methods there.