Scientists say the world's permafrost is getting warmer, with temperatures increasing by an average of 0.3 C over a decade.

A study published Wednesday found the biggest rise in Siberia, where frozen soil temperatures rose by 0.9 C between 2007 and 2016.

Researchers working on the Global Terrestrial Network for Permafrost collected usable data for the entire period from 123 boreholes in the Arctic, Antarctic and high mountain ranges of Europe and Central Asia.

The temperature rose at 71 sites, sank at 12 and remained unchanged at 40.

Scientists say the increases track global warming generally. They noted that thawing permafrost — already recorded at five of the sites — contains organic matter that can release greenhouse gases, further stoking climate change.