An intense heat wave gripped Siberia during the first half of 2020. Temperatures far higher than normal across this northern stretch of Russia would have been impossible without human-caused climate change. That’s the finding of a new study.
The study’s authors, part of the World Weather Attribution Network, relied on the fairly new field of attribution science. Climate change made the prolonged heat in the region at least 600 times more likely, they find. It may have been as much as 99,000 times more likely.
“We wouldn’t expect the natural world to generate [such a heat wave] in anything less than 800,000 years or so,” said Andrew Ciavarella. He’s a climate scientist with the U.K. Met Office in Exeter, England. He spoke July 14 in a news conference. It’s “effectively impossible without human influence.”
The new study was posted online July 15. It examined two aspects of the heat wave. The first was the persistence and intensity of average temperatures across Siberia this past January to June. The second was daily maximum temperatures during June 2020 in Verkhoyansk. This is a remote town in Siberia.
Data collected by NASA’s Aqua satellite show that temperatures on land in Siberia from March 19 through June 20, 2020, were much higher than the average March–June temperatures from 2003 to 2018. Deep red values indicate regions more than 8 degrees Celsius (14.4 degrees Fahrenheit) higher than average. Blue values are colder than average. The town of Verkhoyansk (dot) logged a record high temperature of 38° C (100.4° Fahrenheit) on June 20.
Temperatures in Siberia, March 19–June 2020 compared with spring averages 2003–2018
Verkhoyansk made international headlines earlier this year. Although north of the Arctic Circle, it logged a record high temperature of 38° Celsius (100.4° Fahrenheit) on June 20.
The record was just one extreme in a larger and long event in this region. The heat led to a series of human and natural disasters. They included wildfires across Siberia. There also was the collapse of a fuel tank in the mining city of Norilsk. Sagging permafrost led to the tank spilling oil, which polluted the Ambarnaya River. The health of people in the region suffered from the heat, too.
The researchers gathered data from Siberian weather stations. They assessed the rarity of the temperatures these logged and trends in local temperatures. Then they compared these with hundreds of climate simulations. Those computer models used different scenarios of greenhouse-gas warming.
Had such a hot spell occurred in 1900 instead of 2020, it would have been at least 2 degrees C (3.6 degrees F) cooler on average, the researchers found. In Verkhoyansk, climate change amped up June temperatures by at least 1 degree C (1.8 degrees F) relative to 1900. And such heat waves are likely to become more common in the near future. By 2050, temperatures in Siberia could rise by between 2.5 degrees C (4.5 degrees F) to as much as 7 degrees C (12.6 degrees F) compared to 1900, the report finds.