Temperature extremes of 2022 reduced carbon uptake by forests in Europe

Abstract The year 2022 saw record breaking temperatures in Europe during both summer and fall. Close to 30% of the European continent was under severe summer drought with a similarly large area affected (3.0 million km 2 ) as during the recent 2018 drought, but now located in central and southeastern Europe. Multiple sets of observations suggest a reduction of net ecosystem carbon exchange in summer (57-62 TgC) over this area, and specific sites in France even showed a widespread summertime carbon release by forests, as well as wildfires. A warm fall with prolonged carbon uptake offered only partial compensation (up to 32%) for the carbon uptake lost due to drought. This severity of this second drought event in 5 years suggests these impacts to no longer be exceptional, and important to factor into Europe's developing plans for net-zero greenhouse gas emissions that rely on carbon sequestration by forests.