Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions

Chang, K.-Y.; Riley, W. J.; Knox, S. H.; Jackson, R. B.; McNicol, G.; Poulter, B.; Aurela, M.; Baldocchi, D.; Bansal, S.; Bohrer, G.; Campbell, D. I.; Cescatti, A.; Chu, H.; Delwiche, K. B.; Desai, A. R.; Euskirchen, E.; Friborg, T.; Goeckede, M.; Helbig, M.; Hemes, K. S.

doi:10.1038/s41467-021-22452-1

Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions

Author(s)

Chang, K.-Y.

Riley, W. J.

Knox, S. H.

Jackson, R. B.

McNicol, G.

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Date Issued

2021

Type

article

Volume

12

Issue

1

DOI

10.1038/s41467-021-22452-1

Journal

NATURE COMMUNICATIONS

Abstract

Wetland methane (CH4) emissions (FCH4 ) are important in global carbon budgets and climate change assessments. Currently, FCH4 projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent FCH4 temperature dependence across spatial scales for use in models; however, sitelevel studies demonstrate that FCH4 are often controlled by factors beyond temperature. Here, we evaluate the relationship between FCH4 and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between FCH4 and temperature, suggesting larger FCH4 sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.

Handle

http://hdl.handle.net/2067/43340