Nonlinear response of Asian summer monsoon precipitation to emission reductions in South and East Asia

Herbert, Ross, Wilcox, Laura J., Joshi, Manoj ORCID: https://orcid.org/0000-0002-2948-2811, Highwood, Ellie and Frame, Dave (2022) Nonlinear response of Asian summer monsoon precipitation to emission reductions in South and East Asia. Environmental Research Letters, 17 (1). ISSN 1748-9326

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Abstract

Anthropogenic aerosols over South and East Asia currently have a stronger impact on the Asian Summer Monsoon (ASM) than greenhouse gas emissions, yet projected aerosol emission changes in these regions are subject to considerable uncertainties such as timescale, location, or emission type. We use a circulation/climate model with idealised aerosol distributions to demonstrate that the sum of ASM responses to aerosol emission reductions in each region is very different to the response to simultaneous reductions in both regions, implying the ASM response to aerosol emissions reductions is highly nonlinear. The phenomenon is independent of whether aerosols are scattering or absorbing, and results from interaction of induced atmospheric circulation changes. The nonlinearity from interactions between aerosol forcing from different regions represents a new source of uncertainty in projections of ASM changes over the next 30-40 years, and may limit the utility of country-dependent aerosol trajectories when considering their Asia-wide effects, though we recommend further work to establish whether the nonlinearity is buffered by other drivers. To understand likely changes in the ASM due to aerosol reductions, countries will need to accurately take account of emissions reductions from across the wider region, rather than approximating them using simple scenarios and emulators. The nonlinearity in the response to forcing therefore presents a regional public goods issue for countries affected by the ASM, as the costs and benefits of aerosol emissions reductions are not internalised; in fact, forcings from different countries such as India and China work jointly to determine outcomes across the region.

Item Type:	Article
Uncontrolled Keywords:	sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
Faculty \ School:	Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	University of East Anglia Schools > Faculty of Science > Tyndall Centre for Climate Change Research Faculty of Science > Research Centres > Tyndall Centre for Climate Change Research Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit
Depositing User:	LivePure Connector
Date Deposited:	19 Nov 2021 01:40
Last Modified:	16 Jun 2023 00:26
URI:	https://ueaeprints.uea.ac.uk/id/eprint/82223
DOI:	10.1088/1748-9326/ac3b19

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