Open AccessSiberian 2020 heatwave increased spring CO2 uptake but not annual CO2 uptake
Author(s) -
Mi Hye Kwon,
Ashley P. Ballantyne,
Philippe Ciais,
Ana Bastos,
Frédéric Chevallier,
Zhi Hua Liu,
Julia K. Green,
Chunjing Qiu,
John S. Kimball
Publication year - 2021
Publication title -
environmental research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.37
H-Index - 124
ISSN - 1748-9326
DOI - 10.1088/1748-9326/ac358b
Subject(s) - environmental science , latitude , northern hemisphere , spring (device) , sink (geography) , carbon dioxide , climate change , atmospheric sciences , climatology , ecosystem , carbon sink , respiration , ecology , biology , geography , geology , mechanical engineering , botany , cartography , geodesy , engineering
Siberia experienced an unprecedented strong and persistent heatwave in winter to spring of 2020. Using bottom–up and top–down approaches, we evaluated seasonal and annual CO 2 fluxes of 2020 in the northern hemisphere (north of 30 °N), focusing on Siberia where the pronounced heatwave occurred. We found that, over Siberia, CO 2 respiration loss in response to the pronounced positive winter temperature anomaly was greater than in previous years. However, continued warming in the spring enhanced photosynthetic CO 2 uptake, resulting in the largest seasonal transition in net ecosystem CO 2 exchange; that is, the largest magnitude of the switch from the net CO 2 loss in winter to net CO 2 uptake in spring until June. However, this exceptional transition was followed by the largest reduction in CO 2 uptake in late summer due to multiple environmental constraints, including a soil moisture deficit. Despite a substantial increase of CO 2 uptake by 22 ± 9 gC m −2 in the spring in response to the heatwave, the mean annual CO 2 uptake over Siberia was slightly lower (3 ± 13 gC m −2 yr −1 ) than the average of the previous five years. These results highlight the highly dynamic response of seasonal carbon fluxes to extreme temperature anomalies at high latitudes, indicating a seasonal compensation between abnormal uptake and release of CO 2 in response to extreme warmth that may limit carbon sink capacity in high northern latitudes.