Soil temperatures in permafrost regions around the world have increased by an average of 0.3 degrees Celsius over a decade, scientists say.
A study published in the online journal Nature Communications on January 16 found that the effect was most pronounced in northeast and northwest Siberia, where the temperature of the frozen soil rose by 0.9 degree Celsius between 2007 and 2016.
The air temperature in these two regions rose by an average of 0.61 degrees Celsius in the same period.
For the study, researchers working on the Global Terrestrial Network for Permafrost (GTN-P) collected usable data from 123 boreholes in the Arctic, Antarctic, and high mountain ranges of Europe and Central Asia.
The temperature rose at 71 of the sites, sank at 12, and remained unchanged at 40, the researchers said.
They also noted that thawing permafrost, already recorded at five of the boreholes, contains organic matter that can release carbon dioxide and methane, further stoking climate change.
"All this data tells us that the permafrost isn't simply warming on a local and regional scale, but worldwide and at virtually the same pace as climate warming, which is producing a substantial warming of the air and increased snow thickness, especially in the Arctic,” said Professor Guido Grosse, head of the Permafrost Research Section at the Alfred Wegener Institute in Potsdam.
"These two factors in turn produce a warming of the once permanently frozen ground," he said in a statement.