In another example of the dangerous cycles of global warming, thawing arctic ice is releasing methane gas, which in turn contributes greatly to global warming. An article in June’s Scientific American describes the problems presented by pockets of methane gas formerly trapped in arctic permafrost, and now being released as arctic ice begins to melt.

Methane is one of the primary gases responsible for global warming, and traps far more heat from the sun than an identical quantity of carbon dioxide. Methane comes from a number of places, including manure, landfills, and cow burps. The abundance of methane sources allowed the methane released from thawed permafrost to go overlooked for a long time, but this arctic methane still poses a serious threat. Up to 50 billion tons of methane, 10 times more than is currently found in earth’s atmosphere, could be released in a complete arctic thaw.

Many climate models suggest that a majority of the Arctic’s permafrost could be thawed by the end of this century, and those models fail to consider the additional warming effects of permafrost methane. As arctic thaws and methane is released into the atmosphere, the rate of thawing will increase, starting a perilous cycle of climate change.