Climate influence on the 2019 fires in Amazonia.

Area of Science:

• Climatology
• Ecology
• Remote Sensing

Background:

• Amazonia experienced severe fires in August 2019, causing significant environmental and economic losses.
• While deforestation is a known driver, anomalous climate conditions may have also contributed to the 2019 fire events.
• Understanding climate's role is crucial for predicting and mitigating future extreme fire occurrences.

Purpose of the Study:

• To investigate the influence of climate conditions on Amazonia fires in August 2019.
• To identify the underlying mechanisms linking climate anomalies to fire events.
• To explore the potential for global tropical sea surface temperature-based fire prediction.

Main Methods:

• Statistical correlation and multiple linear regression analyses were employed.
• Utilized satellite-based fire products and multiple observational/reanalyzed climate datasets from 2001-2019.
• Examined the relationship between climate variables (precipitation, humidity, SST) and fire anomalies.

Main Results:

• Low precipitation and relative humidity in southern Amazonia were primary drivers of 2019 fire anomalies, contributing to 38.9 ± 9.5% of pyrogenic carbon emissions.
• Southerly wind anomalies suppressed water vapor transport, linked to warmer North Atlantic and colder eastern Pacific sea surface temperatures.
• Indian Ocean sea surface temperature anomalies were identified as a significant, previously unrecognized factor influencing Amazonia fires.

Conclusions:

• Climate conditions, particularly sea surface temperature anomalies in the Indian and Pacific Oceans, play a critical role in Amazonia fire events.
• The study establishes a link between the El Niño-Southern Oscillation (ENSO) warm phase and dry-season fires via tropical eastern Pacific SST.
• Findings provide a theoretical basis for global tropical SST-based fire prediction, enhancing the ability to mitigate extreme fire impacts in Amazonia.