Northern Hemisphere permafrost contains twice as much carbon as the atmosphere and could significantly amplify global warming, a U.N. report says. Should thawing accelerate as expected with climate change, the report by the U.N. Environment Program said, it will accelerate hazards of carbon dioxide and methane emissions from warming permafrost which have not so far been included in climate-prediction modeling. \"Permafrost is one of the keys to the planet\'s future because it contains large stores of frozen organic matter that, if thawed and released into the atmosphere, would amplify current global warming and propel us to a warmer world,\" U.N. Undersecretary General and UNEP Executive Director Achim Steiner said. The scientific evidence of the potential impacts of warming permafrost has only begun to go mainstream in the last few years, and as a truly \"emerging issue\" could not have been included in climate change modeling to date, the UNEP report said. \"Its potential impact on the climate, ecosystems and infrastructure has been neglected for too long,\" Steiner said. \"This report seeks to communicate to climate-treaty negotiators, policy makers and the general public the implications of continuing to ignore the challenges of warming permafrost.\" Permafrost consists of an active layer of up to 6 feet in thickness, which thaws each summer and refreezes each winter, with permanently frozen soil beneath. Should the active layer increase in thickness due to warming, huge quantities of organic matter stored in the frozen soil would begin to thaw and decay, releasing large amounts of CO2 and methane into the atmosphere, the UNEP report warned.