British researchers have indicated that a large area of frozen Siberian ground may be thawed by global warming, resulting in a dangerous amount of carbon emissions from the soil.
The team, an international group of researchers from the UK, Russia, Switzerland and Mongolia and led by Oxford University scientists, has determined that a rise of 2.7 degrees Fahrenheit could release over 1,000 gigatons of carbon dioxide and methane, leading to a potential acceleration in warming.
The researchers came to the conclusion after studying stalactites and stalagmites within caves beneath the "permafrost frontier:" an area of permanently frozen ground tens of hundreds of yards thick. Stalactites and stalagmites can only be found after rainwater and melted snow drips into the caves. Accordingly, 500,000 years of permafrost conditions are recorded by the formations. Scientists believe that a warming period that took place 400,000 years ago indicates a warming of 2.7 degrees Fahrenheit would be sufficient to considerably thaw permafrost even further north than its current southern limit.
Permafrost currently exists north of around 60 degrees latitude in the northern hemisphere, going halfway down Russia and Canada and stretching across Greenland. The warmest interglacial period pushed the permafrost boundary much further north. The researchers warn that if a similar event were to take place, this time caused by humans, a large amount of carbon could be released into the atmosphere.
At the same time, it is unknown how much carbon is held in permafrost. As Professor Julian Murton of the University of Sussex told Carbon Brief, "The area of permafrost in the northern hemisphere is larger than the whole of Canada's land mass (about 10 million square kilometers) and the number of [carbon measurements] is very limited."
That said, the study remains a cause for concern.
"With substantial global warming projected during the 21st century, which almost certainly will be amplified in Arctic regions (due to feedback effects in the global climate system)," Murton said, "we should be concerned about greenhouse gas release from thawing permafrost."
