Warming is causing soil-based microorganisms to release carbon dioxide in a potentially catastrophic process that could add at least as much carbon to the atmosphere as the fossil fuel industry emitted in the mid-20th century, a study finds.
If Arctic soils melt and release frozen carbon, the impact would cost almost half the world’s annual gross domestic product, researchers say.
Arctic warming is causing organic carbon that has been frozen deep in the soil for millennia to be released rapidly into the air as CO2, with potentially catastrophic impacts on the climate.
A re-examination of the true social costs of greenhouse gas emissions suggests they may have been seriously under-estimated, researchers say.
If the Earth's average global temperature rises by another few tenths of a degree, a large area of Siberian permafrost will start to melt uncontrollably, releasing 160 to 290 billion tonnes of carbon dioxide into the atmosphere in the years that follow. But the dangers have been overhyped, a British climate scientist says.
The melting of Arctic ice frozen for many thousands or even millions of years is speeding up a potential route for carbon frozen deep below ground level to seep into the atmosphere.