The Equilibrium Climate Response to Sulfur Dioxide and Carbonaceous Aerosol Emissions from East and Southeast Asia

TL;DR

This study uses climate modeling to quantify how aerosols from East and Southeast Asia influence global and regional climate, revealing significant cooling effects and local precipitation suppression.

Contribution

It provides new estimates of the climate impact of Asian aerosols using the Community Earth System Model, highlighting the regional effects and challenging previous assumptions about remote impacts.

Findings

Asian aerosols cause a global cooling of approximately -0.49 W/m².

Sulfur dioxide emissions account for about half of the cooling effect.

Local suppression of precipitation over East and Southeast Asia observed, with no clear remote effects on Australia and West Africa.

Abstract

We investigate the equilibrium climate response to East and Southeast Asian emissions of carbonaceous aerosols and sulfur dioxide, a precursor of sulfate aerosol. Using the Community Earth System Model, with the Community Atmosphere Model version 5.3, we find that anthropogenic aerosol emissions from East and Southeast Asia exert a global mean net radiative effect of -0.49$\pm$0.04 W m$^{-2}$. Approximately half of this cooling effect can be attributed to anthropogenic sulfur dioxide emissions. The aerosol emissions drive widespread cooling across the Northern Hemisphere. Strong suppression of precipitation occurs over East and Southeast Asia, indicating that anthropogenic aerosol emissions may impact water resources locally. However, in contrast to previous research, we find no clear evidence of remote effects on precipitation over Australia and West Africa. We recommend further investigation of possible remote effects.