London/Moscow — After the hottest winter on record, the Russian spring has brought a Siberian heat wave that is reigniting fires still smouldering since last year.

The region has had unusually warm weather this month, with temperatures in parts of the Arctic up to 16°C higher than usual, says Russia’s federal meteorological service.

Hot, dry weather dried out vegetation sooner than normal leading to wildfires in the boreal forests with some blazes starting in March and stretching into May. An early start typically means a longer fire season, say academics at Swansea University.

Though sparsely populated, the vast region’s state can have a global impact.

“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 rain this summer, compounding what was a mild winter and threatening droughts, according to scientists at the Copernicus Climate Change Service.

Wildfires and hotter temperatures get sea-ice melt going sooner. The receding of ice in the Arctic opened up the Northern Sea Route to tanker traffic a month earlier than usual this year. This is the shortest and cheapest route for cargoes of liquefied natural gas produced in the Russian Arctic to reach Asia.

“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 had some of its worst wildfires last summer, which burned more than 13-million hectares of land, an area the size of Greece. In June, they released as much carbon dioxide as Sweden does in a year.

Many of these fires that lit peatlands released carbon from thousands of years ago. Worse, peatlands can burn under the snowpack of winter. Early data published by Copernicus scientists on Wednesday indicates that these “zombie fires” are probably reigniting as the heat wave takes hold.

Scientists of the service’s monitoring service were “bracing themselves for intense fire activity in the Arctic after an unusually warm spring and seeing signals of heat anomaly sources from satellite images”, they said.  

Huge wildfires also burned in the Amazon, Indonesia, Australia and the Arctic Circle in the past year, destroying forests and vulnerable animal species and releasing billions of tonnes of greenhouse gases into the atmosphere.