Emissions from thawing permafrost may contribute more to global warming than deforestation this century, according to a commentary in the journal Nature.
Arctic warming of 7.5 degrees Celsius (13.5 degrees Fahrenheit) this century may unlock the equivalent of 380 billion tons of carbon dioxide as soils thaw, allowing carbon to escape as CO2 and methane, University of Florida and University of Alaska biologists wrote in an article in Nature published yesterday. Two degrees of warming would release a third of that, they said.
“We calculate that permafrost thaw will release the same order of magnitude of carbon as deforestation if current rates of deforestation continue,” the researchers said. “Because these emissions include significant quantities of methane, the overall effect on climate could be 2.5 times larger.”
The Arctic is an important harbinger of climate change because the United Nations calculates it’s warming at almost twice the average rate for the planet. The study adds to pressure on United Nations climate treaty negotiators from more than 190 countries attending two weeks of talks in Durban, South Africa that began Nov. 28.
The International Energy Agency this month said with current energy policies worldwide, the global average temperature may rise by more than 3.5 degrees. With the Arctic warming faster than the rest of the world, that could imply a 7-degree rise in the region. The Arctic warming has led to record melting of sea ice in recent years and the retreat of glaciers in Greenland.
The researchers based their commentary on a survey of 41 permafrost scientists from around the world, who were asked to calculate what percentage of the surface permafrost is likely to thaw, how much carbon will be released, and how much of that carbon will be methane over different time frames and for four different warming scenarios.
“Our survey outlines the additional risk to society caused by thawing of the frozen north, and underscores the urgent need to reduce atmospheric emissions from fossil-fuel use and deforestation,” the scientists said. “This will help to keep permafrost carbon frozen in the ground.”
Researchers at the Permafrost Carbon Research Network also contributed to the commentary piece.