Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere


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Johannes.Freitag [ at ] awi.de

Abstract

Fire plays a pivotal role in shaping terrestrial ecosystems and the chemical composition of the atmosphere and thus influences Earth’s climate. The trend and magnitude of fire activity over the past few centuries are contro- versial, which hinders understanding of preindustrial to present-day aerosol radiative forcing. Here, we present evidence from records of 14 Antarctic ice cores and 1 central Andean ice core, suggesting that historical fire activity in the Southern Hemisphere (SH) exceeded present-day levels. To understand this observation, we use a global fire model to show that overall SH fire emissions could have declined by 30% over the 20th century, possibly because of the rapid expansion of land use for agriculture and animal production in middle to high latitudes. Radiative forcing calculations suggest that the decreasing trend in SH fire emissions over the past century largely compensates for the cooling effect of increasing aerosols from fossil fuel and biofuel sources.



Item Type
Article
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Primary Division
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Helmholtz Cross Cutting Activity (2021-2027)
N/A
Peer revision
ISI/Scopus peer-reviewed
Publication Status
Published
Eprint ID
55209
DOI 10.1126/sciadv.abc1379

Cite as
Liu, P. , Kaplan, J. O. , Mickley, L. J. , Li, Y. , Chellman, N. J. , Arienzo, M. M. , Kodros, J. K. , Pierce, J. R. , Sigl, M. , Freitag, J. , Mulvaney, R. , Curran, M. A. J. and McConnell, J. R. (2021): Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere , Science Advances, 7 (22) . doi: 10.1126/sciadv.abc1379


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Antartic Land Expeditions > 2018 Antartic Land Expeditions


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