Climate influence on the 2019 fires in Amazonia

Xiao Dong; Fang Li; Zhongda Lin; Sandy P Harrison; Yang Chen; Jong-Seong Kug

doi:10.1016/j.scitotenv.2021.148718

Climate influence on the 2019 fires in Amazonia

Sci Total Environ. 2021 Nov 10:794:148718. doi: 10.1016/j.scitotenv.2021.148718. Epub 2021 Jun 26.

Authors

Xiao Dong¹, Fang Li¹, Zhongda Lin², Sandy P Harrison³, Yang Chen⁴, Jong-Seong Kug⁵

Affiliations

¹ International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
² State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China. Electronic address: zdlin@mail.iap.ac.cn.
³ School of Archaeology, Geography & Environmental Science, Reading University, Reading, UK; Leverhulme Centre for Wildfires, Environmental and Society, Imperial College London, South Kensington, London, UK; Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China.
⁴ Department of Earth System Science, University of California, Irvine, CA, USA.
⁵ Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, South Korea.

PMID: 34217088
DOI: 10.1016/j.scitotenv.2021.148718

Abstract

Amazonia experienced unusually devastating fires in August 2019, leading to huge regional and global environmental and economic losses. The increase in fires has been largely attributed to anthropogenic deforestation, but anomalous climate conditions could also have contributed. This study investigates the climate influence on Amazonia fires in August 2019 and underlying mechanisms, based on statistical correlation and multiple linear regression analyses of 2001-2019 satellite-based fire products and multiple observational or reanalyzed climate datasets. Positive fire anomalies in August 2019 were mainly located in southern Amazonia. These anomalies were mainly driven by low precipitation and relative humidity, which increased fuel dryness and contributed to 38.9 ± 9.5% of the 2019 anomaly in pyrogenic carbon emissions over the southern Amazonia. The dry conditions were associated with southerly wind anomalies over southern Amazonia that suppressed the climatological southward transport of water vapor originating from the Atlantic. The southerly wind anomalies were caused by the combination of a Gill-type cyclonic response to the warmer North Atlantic sea surface temperature (SST), and enhancement of the Walker and Hadley circulations over South America due to the colder SST in the eastern Pacific, and a mid-latitude wave train triggered by the warmer condition in the western Indian Ocean. Our study highlights, for the first time, the important role of Indian Ocean SST for fires in Amazonia. It also reveals how cold SST anomalies in the tropical eastern Pacific link the warm phase of the El Niño-Southern Oscillation (ENSO) in the preceding December-January to the dry-season fires in Amazonia. Our findings can develop theoretical basis of global tropical SST-based fire prediction, and have potential to improve prediction skill of extreme fires in Amazonia and thus to take steps to mitigate their impacts which is urgency given that dry conditions led to the extreme fires are becoming common in Amazonia.

Keywords: 2019 Amazonia fires; Climate variability; Drought; Fire carbon emissions; Large-scale atmospheric circulation; Sea surface temperature.

MeSH terms

Brazil
Climate Change
Climate*
Fires*
Seasons