Don’t panic ... yet. But the great methane menace may be upon us sooner than most scientists thought. Perhaps you weren’t worried about this to begin with, but at some point, as the planet warms, the permanently frozen seabed under the Arctic ice—the permafrost—will thaw. And when that happens, Mother Earth will, so to speak, expel gas, after which nothing will ever be quite the same again: the planet will get hotter faster, and disastrous weather will grow more catastrophic, exacting a huge cost on humankind. Some scientists think that process will be very slow, over multiple millennia. But if Prof. Peter Wadhams is right, the time to prepare is now. He argues in the scientific journal Nature that the tipping point could come as early as 2015, when Arctic sea ice disappears during the month of September. By 2035, according to studies he and his colleagues have conducted off the coast of Siberia, the ice could be gone six months a year. “The loss of sea ice leads to seabed warming, which leads to offshore permafrost melt, which leads to methane release, which leads to enhanced warming,” Wadhams explained to The Guardian. The rest will be history.