June 16, 2006: Study Suggests Melting of Siberian Permafrost Could Release Far More Carbon than Previously Thought

A team of Russian and American scientists conclude in a study published in the journal Science that the melting of Siberia’s carbon-rich permafrost could result in the release of about 500 billion tons of carbon dioxide into the atmosphere over the next 100 years. That would almost double the atmosphere’s current load of the greenhouse gas which currently stands at about 700 billion tons. When permafrost melts, it makes organic material available to microbes which convert much of the carbon in it into carbon dioxide. This process results in what is known as a “positive feedback” loop whereby the increased presence of greenhouse gases leads to more warming and consequently to the melting of more carbon-rich permafrost. Leading climate models do not factor in the melting of Siberia’s permafrost, which covers some 400,000 square miles, when trying to make predictions about climate change. Previous estimates of the amount of carbon contained in the permafrost have put the value much lower. “We have known [about] the permafrost in Siberia before,” explains atmospheric scientist Bala Govindasamy, “Previous estimates for global permafrost [are] between 200 and 400 [billion tons]. This study has found higher carbon content in the Siberian permafrost and estimates that the total global amount could be about 1,000 [billion tons].” This report “makes it kind of scary—it means there’s a form of climate risk that we really haven’t got a good handle on,” notes Chris Field, director of the Carnegie Institution’s Department of Global Ecology at Stanford. Another scientist, paleoclimatologist David Anderson of the National Oceanic and Atmospheric Administration’s National Climate Prediction Center, tells the San Francisco Chronicle that carbon dioxide released from Siberia “could raise temperatures dramatically beyond the current projections. Second, it could raise the rate at which temperatures rise.” [Los Angeles Times, 6/16/2006; San Francisco Chronicle, 6/16/2006; Zimov, Schuur, and Chapin, 6/16/2006]