The Impact of Stratospheric Aerosol Injection on Extreme Fire Weather Risk

Abstract

Stratospheric aerosol injection (SAI) would potentially be effective in limiting global warming and preserving large‐scale temperature patterns; however, there are still gaps in understanding the impact of SAI on wildfire risk. In this study, extreme fire weather is assessed in an Earth system model experiment that deploys SAI beginning in 2035, targeting a global temperature increase of 1.5°C above pre‐industrial levels under a moderate warming scenario. After SAI deployment, increases in extreme fire weather event frequency from climate change are dampened over much of the globe, including the Mediterranean, northeast Brazil, and eastern Europe. However, SAI has little impact over the western Amazon and northern Australia and causes larger increases in extreme fire weather frequency in west central Africa relative to the moderate emissions scenario. Variations in the impacts of warming and SAI on moisture conditions on different time scales determine the spatiotemporal differences in extreme fire weather frequency changes, and are plausibly linked to changes in synoptic‐scale circulation. This study highlights that regional and spatial heterogeneities of SAI climate effects simulated in a model are amplified when assessing wildfire risk, and that these differences must be accounted for when quantifying the possible benefit of SAI.

Natural Disasters are Not All Natural

“…Aluminum nanoparticles are also well known for their pyrophoric capacity and the high energy they emit during combustion [102], thus amplifying the risk and severity of wildfires. In addition, geoengineering simulations showed that SAI induces drought [103], leading to an increase in the frequency of extreme fires in some regions [104].…”

The interaction of Solar Radiation Modification and Earth System Tipping Elements

“…However, this analysis is limited as it looks at annual precipitation rather than looking at droughts, with the latter a much stronger driver of Amazon tipping. Touma et al , (2023) uses an SAI scheme to keep temperature close to 1.5 O C above pre-industrial, and sees increases in drying and fires in the West Amazon when compared to SSP2-4.5, whilst a reduction in fires in Northeast Brazil, which includes part of the East Amazon. However, drought severity is found to increase slightly for both regions under SRM when compared to SSP2-4.5.…”