Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town

Anthropogenic forcing of the climate is estimated to have increased the likelihood of the 2015–2017 Western Cape drought, also called ‘Day Zero’ drought, by a factor of three, with a projected additional threefold increase of risk in a world with 2 °C warming. Here, we assess the potential for geoen...

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Main Authors: Romaric C Odoulami, Mark New, Piotr Wolski, Gregory Guillemet, Izidine Pinto, Christopher Lennard, Helene Muri, Simone Tilmes
Format: Article
Language:English
Published: IOP Publishing 2020-01-01
Series:Environmental Research Letters
Subjects:
Online Access:https://doi.org/10.1088/1748-9326/abbf13
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author Romaric C Odoulami
Mark New
Piotr Wolski
Gregory Guillemet
Izidine Pinto
Christopher Lennard
Helene Muri
Simone Tilmes
author_facet Romaric C Odoulami
Mark New
Piotr Wolski
Gregory Guillemet
Izidine Pinto
Christopher Lennard
Helene Muri
Simone Tilmes
author_sort Romaric C Odoulami
collection DOAJ
description Anthropogenic forcing of the climate is estimated to have increased the likelihood of the 2015–2017 Western Cape drought, also called ‘Day Zero’ drought, by a factor of three, with a projected additional threefold increase of risk in a world with 2 °C warming. Here, we assess the potential for geoengineering using stratospheric aerosols injection (SAI) to offset the risk of ‘Day Zero’ level droughts in a high emission future climate using climate model simulations from the Stratospheric Aerosol Geoengineering Large Ensemble Project. Our findings suggest that keeping the global mean temperature at 2020 levels through SAI would offset the projected end century risk of ‘Day Zero’ level droughts by approximately 90%, keeping the risk of such droughts similar to today’s level. Precipitation is maintained at present-day levels in the simulations analysed here, because SAI (i) keeps westerlies near the South Western Cape in the future, as in the present-day, and (ii) induces the reduction or reversal of the upward trend in southern annular mode. These results are, however, specific to the SAI design considered here because using different model, different SAI deployment experiments, or analysing a different location might lead to different conclusions.
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spelling doaj.art-3e844ea7d36d4675a456366bd13b417f2023-08-09T14:57:25ZengIOP PublishingEnvironmental Research Letters1748-93262020-01-01151212400710.1088/1748-9326/abbf13Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape TownRomaric C Odoulami0https://orcid.org/0000-0001-8228-1608Mark New1https://orcid.org/0000-0001-6082-8879Piotr Wolski2https://orcid.org/0000-0002-6120-6593Gregory Guillemet3Izidine Pinto4https://orcid.org/0000-0002-9919-4559Christopher Lennard5https://orcid.org/0000-0001-6085-0320Helene Muri6https://orcid.org/0000-0003-4738-493XSimone Tilmes7https://orcid.org/0000-0002-6557-3569African Climate and Development Initiative, University of Cape Town , Cape Town, South AfricaAfrican Climate and Development Initiative, University of Cape Town , Cape Town, South AfricaClimate System Analysis Group, University of Cape Town , Cape Town, South AfricaInstitut National des Sciences Appliquées , Lyon, FranceClimate System Analysis Group, University of Cape Town , Cape Town, South AfricaClimate System Analysis Group, University of Cape Town , Cape Town, South AfricaDepartment of Energy and Process Engineering, Industrial Ecology Programme, Norwegian University of Science and Technology , Trondheim, NorwayAtmospheric Chemistry, Observations, and Modeling Laboratory, National Center for Atmospheric Research , Boulder, Colorado, United States of AmericaAnthropogenic forcing of the climate is estimated to have increased the likelihood of the 2015–2017 Western Cape drought, also called ‘Day Zero’ drought, by a factor of three, with a projected additional threefold increase of risk in a world with 2 °C warming. Here, we assess the potential for geoengineering using stratospheric aerosols injection (SAI) to offset the risk of ‘Day Zero’ level droughts in a high emission future climate using climate model simulations from the Stratospheric Aerosol Geoengineering Large Ensemble Project. Our findings suggest that keeping the global mean temperature at 2020 levels through SAI would offset the projected end century risk of ‘Day Zero’ level droughts by approximately 90%, keeping the risk of such droughts similar to today’s level. Precipitation is maintained at present-day levels in the simulations analysed here, because SAI (i) keeps westerlies near the South Western Cape in the future, as in the present-day, and (ii) induces the reduction or reversal of the upward trend in southern annular mode. These results are, however, specific to the SAI design considered here because using different model, different SAI deployment experiments, or analysing a different location might lead to different conclusions.https://doi.org/10.1088/1748-9326/abbf13solar radiation managementgeoengineeringdroughtDay ZeroCape Townattribution science
spellingShingle Romaric C Odoulami
Mark New
Piotr Wolski
Gregory Guillemet
Izidine Pinto
Christopher Lennard
Helene Muri
Simone Tilmes
Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
Environmental Research Letters
solar radiation management
geoengineering
drought
Day Zero
Cape Town
attribution science
title Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
title_full Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
title_fullStr Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
title_full_unstemmed Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
title_short Stratospheric Aerosol Geoengineering could lower future risk of ‘Day Zero’ level droughts in Cape Town
title_sort stratospheric aerosol geoengineering could lower future risk of day zero level droughts in cape town
topic solar radiation management
geoengineering
drought
Day Zero
Cape Town
attribution science
url https://doi.org/10.1088/1748-9326/abbf13
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