Unusual characteristics of the carbon cycle during the 2015−2016 El Niño

Wang, Kai; Wang, Xuhui; Piao, Shilong; Chevallier, Frédéric; Mao, Jiafu; Shi, Xiaoying; Huntingford, Chris ORCID: https://orcid.org/0000-0002-5941-7770; Bastos, Ana; Ciais, Philippe; Xu, Hao; Keeling, Ralph F.; Pacala, Stephen W.; Chen, Anping. 2021 Unusual characteristics of the carbon cycle during the 2015−2016 El Niño. Global Change Biology, 27 (16). 3798-3809. https://doi.org/10.1111/gcb.15669

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Official URL: http://dx.doi.org/10.1111/gcb.15669

Abstract/Summary

The 2015−2016 El Niño was one of the strongest on record, but its influence on the carbon balance is less clear. Using Northern Hemisphere atmospheric CO2 observations, we found both detrended atmospheric CO2 growth rate (CGR) and CO2 seasonal-cycle amplitude (SCA) of 2015−2016 were much higher than that of other El Niño events. The simultaneous high CGR and SCA were unusual, because our analysis of long-term CO2 observations at Mauna Loa revealed a significantly negative correlation between CGR and SCA. Atmospheric inversions and terrestrial ecosystem models indicate strong northern land carbon uptake during spring but substantially reduced carbon uptake (or high emissions) during early autumn, which amplified SCA but also resulted in a small anomaly in annual carbon uptake of northern ecosystems in 2015−2016. This negative ecosystem carbon uptake anomaly in early autumn was primarily due to soil water deficits and more litter decomposition caused by enhanced spring productivity. Our study demonstrates a decoupling between seasonality and annual carbon cycle balance in northern ecosystems over 2015−2016, which is unprecedented in the past five decades of El Niño events.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1111/gcb.15669
UKCEH and CEH Sections/Science Areas:	Hydro-climate Risks (Science Area 2017-)
ISSN:	1354-1013
Additional Keywords:	atmospheric CO2 growth rate (CGR), CO2 seasonal-cycle amplitude (SCA), El Niño, net biome productivity (NBP), northern terrestrial ecosystems, soil water deficit
NORA Subject Terms:	Ecology and Environment Meteorology and Climatology
Date made live:	04 Jun 2021 11:12 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/530467

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1111/gcb.15669

UKCEH and CEH Sections/Science Areas:

Hydro-climate Risks (Science Area 2017-)

ISSN:

1354-1013

Additional Keywords:

atmospheric CO2 growth rate (CGR), CO2 seasonal-cycle amplitude (SCA), El Niño, net biome productivity (NBP), northern terrestrial ecosystems, soil water deficit

NORA Subject Terms:

Ecology and Environment
Meteorology and Climatology

Date made live:

04 Jun 2021 11:12 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/530467