Wildfires are ravaging the Arctic, with areas of northern Siberia, northern Scandinavia, Alaska and Greenland engulfed in flames.
Lightning frequently triggers fires in the region but this year they have been worsened by summer temperatures that are higher than average because of climate change.
Plumes of smoke from the fires can be seen from space.
Mark Parrington, a wildfires expert at the Copernicus Atmosphere Monitoring Service (Cams), described them as “unprecedented”.
There are hundreds of fires covering mostly uninhabited regions across eastern Russia, northern Scandinavia, Greenland and Alaska.
But smoke is affecting wider surrounding areas, engulfing some places completely.
Cities in eastern Russia have noted a significant decrease in air quality since the fires started.
The smoke has reportedly reached Russia’s Tyumen region in western Siberia, six time zones away from the fires on the east coast.
Arctic fires are common between May and October and wildfires are a natural part of an ecosystem, offering some benefits for the environment, according to the Alaska Centers website.
But the intensity of these fires, as well as the large area they have taken up, make these unusual.
In June, the fires released an estimated 50 megatonnes of carbon dioxide – the equivalent of Sweden’s annual carbon output, according to Cams.
“It is unusual to see fires of this scale and duration at such high latitudes in June,” said Mr Parrington.
“But temperatures in the Arctic have been increasing at a much faster rate than the global average, and warmer conditions encourage fires to grow and persist once they have been ignited.”
Extremely dry ground and hotter than average temperatures, combined with heat lightning and strong winds, have caused the fires to spread aggressively.
The burning has been sustained by the forest ground, which consists of exposed, thawed, dried peat – a substance with high carbon content.