After the hottest winter on record, the Russian spring has yielded a Siberian heatwave that is reigniting fires still simmering from last year.
The region has witnessed unusually warm weather this month, with temperatures in some parts of the Arctic as much as 16C higher than usual, according to Russia's federal meteorological service.
High temperatures and low precipitation have dried out vegetation sooner than normal, leading to wildfires in the boreal forests, with some blazes starting in March and stretching into May.
"Siberia has a lot of stored carbon," said Cristina Santin Nuno, associate professor at Swansea University.
"What happens to it will affect the planet in a substantial way."
Across Europe, forecasters are braced for sweltering temperatures and little rainfall this summer, compounding what was a mild winter and threatening droughts, according to scientists at the Copernicus Climate Change Service.
Wildfires and hotter temperatures kickstart sea-ice melt sooner.
The receding ice in the Arctic has opened up the Northern Sea route to tanker traffic a month earlier than usual this year.
"Our forecast is [summer wildfires] will begin at the end of June, a month earlier than usual," said Gregory Kuksin, of Greenpeace Russia.
These forecasts come after Siberia saw some of the worst wildfires last summer, which burned more than 13 million hectares of land - an area the size of Greece. In June alone, they released as much carbon dioxide as Sweden does in a year.
Early data indicates that these "zombie" fires are most likely reigniting as the heatwave takes hold.