Part of the Northern Hemisphere has experienced widespread autumn cooling during the most recent decades despite overall warming, but how this contrasting temperature change has influenced the ecosystem carbon exchange remains unclear. Here, we show that autumn cooling has occurred over about half of the area north of 25° N since 2004, producing a weak cooling trend over the period 2004–2018. Multiple lines of evidence suggest an increasing net CO2 release in autumn during 2004–2018. In cooling areas, the increasing autumn CO2 release is due to the larger decrease of gross primary productivity (GPP) growth than total ecosystem respiration (TER) growth suppressed by cooling. In the warming areas, TER increased more than GPP because the warming and wetting conditions are more favourable for TER growth than GPP increase. Despite the opposite temperature trends, there has been a systematic increase in ecosystem carbon release across the Northern Hemisphere middle and high latitudes.
|Number of pages||6|
|Journal||Nature Climate Change|
|Publication status||Published - 2022 Apr|
Bibliographical noteFunding Information:
This work has been supported by the National Key Scientific Research and Development Program of China (grant 2017YFA0603601) and the Strategic Priority Research Program of the Chinese Academy of Sciences (grant XDA20060402). Support from the Swedish BECC and MERGE, as well as STINT (CH2020-8799 and CH2020-8767) are also acknowledged.
© 2022, The Author(s).
Subject classification (UKÄ)
- Climate Research
- Meteorology and Atmospheric Sciences
- Physical Geography
- carbon dioxide
- climate change
- carbon cycle