A global temperature increase of 1.5 degrees Celsius could unleash more than 1,000 gigatons of carbon and methane currently trapped beneath Siberian permafrost and accelerate global climate change, a new study says. In a study conducted in a frozen cave in Siberia, researchers analyzed stalactites and stalagmites which, since they form only when rainwater and snowmelt drip into the caves, provide a glimpse into 500,000 years of changing permafrost conditions. According to their findings, records of an especially warm period 400,000 years ago suggest that a 1.5-degree increase compared to current temperatures would trigger the thawing of permafrost far north of its existing southern boundary. And since permafrost covers 24 percent of the exposed land surface in the Northern Hemisphere, significant thawing could release huge amounts of methane and carbon dioxide, said Anton Vaks, a scientist at Oxford University and lead researcher on the study, published in Science Express. In addition to the effects the loss of permafrost could have on climate, it could have major regional implications, affecting roads, railways, and natural gas facilities built on the frozen landscape.