Siberia is today among the fastest-warming regions on Earth, but in the 7,000 years prior to the Industrial Revolution it saw summer temperatures steadily decline, according to a new study that underscores the profound impact of human-caused climate change on northern Russia.
Scientists analyzed tree rings in partially fossilized wood from Siberia’s Yamal Peninsula to track summer temperatures over the last 7,638 years — tree rings tend to be wider in warm, wet years and thinner in colder, drier years. The wood samples, collected in expeditions carried out over the last four decades, revealed a multi-millennial cooling trend that abruptly reversed at the onset of the Industrial Revolution.
The long-term decline in Siberia’s summer temperatures is consistent with changes in the Earth’s orbit, while the recent warming trend reflects the sudden rise in heat-trapping carbon dioxide over the last 150 years. Today, Siberian summers are warming faster that at any time in the last 7,000 years, reaching unprecedented temperatures. The findings were published in the journal Nature Communications.
The authors write that recent warming “may result in a new climate state in which heatwaves as well as the associated melting of permafrost bodies and occurrence of wildfires may become routine.”
Scientists say the rapid rise in Arctic temperatures is setting the stage for larger and more intense fires. Over the last two decades, wildfires in boreal forests accounted for 70 percent of fire-related forest loss globally. So far this year, wildfires in Siberia have burned more than 8 million acres of forest, an area roughly the size of the Netherlands. More ferocious wildfires and permafrost loss threaten to unleash more greenhouse gases, spurring further warming.