Ice covering the Arctic Ocean reached the lowest level since at least 1979 for July as temperatures spiked in the region, leaving large stretches of Russia’s Siberian coast mostly ice-free.

Sea ice extent in the Arctic last month was 27 percent below the average set between 1981 and 2020, the lowest level ever recorded, with the previous July low set in 2012, according to a monthly report by Europe’s Copernicus agency.

The Arctic, which is warming more than twice as fast as the rest of the planet, has endured a heatwave through spring and summer that saw record-high temperatures, an early start of the fire season and the opening up of usually frozen sea routes to shipping companies.

Satellite readings show ice-free conditions almost everywhere along the so-called Northern Sea Route, which spans through Russia’s northern coast. The region shows the highest levels of ice melting and also the highest temperatures for the Arctic region in July, compared to the historical average, Copernicus said.

Ice begins melting in the Arctic as spring approaches in the northern hemisphere, and then it usually starts building again toward the end of September as the days grow shorter and cooler. Global warming is leading to less ice freezing back every year. The 13 years with the lowest sea-ice extent have occurred in the last 13 years, and sea ice cover this year is on track for the lowest on record.

Last month was also the third-warmest July on record globally, according to Copernicus. July was 0.49 degrees Celsius warmer than the average between 1981 and 2020 around the world. The twelve months to July 2020 were 0.65 degrees Celsius warmer than the historical average.