Siberian 2020 heatwave increased spring CO₂ uptake but not annual CO₂ uptake

Abstract Siberia experienced an unprecedented strong and persistent heatwave in winter to spring of 2020. Using bottom–up top–down approaches, we evaluated seasonal annual CO 2 fluxes 2020 the northern hemisphere (north 30 °N), focusing on where pronounced occurred. We found that, over Siberia, respiration loss response positive temperature anomaly was greater than previous years. However, continued warming enhanced photosynthetic uptake, resulting largest transition net ecosystem exchange; that is, magnitude switch from uptake until June. this exceptional followed by reduction late summer due multiple environmental constraints, including a soil moisture deficit. Despite substantial increase 22 ± 9 gC m −2 heatwave, mean slightly lower (3 13 yr −1 ) average five These results highlight highly dynamic carbon extreme anomalies at high latitudes, indicating compensation between abnormal release warmth may limit sink capacity latitudes.