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University of Nottingham (2021)

Risks to global water resources from geoengineering the climate with solar radiation management

Burnell, Lorna

Titre : Risks to global water resources from geoengineering the climate with solar radiation management

Auteur : Burnell, Lorna

Université de soutenance : University of Nottingham

Grade : Doctor of Philosophy (PhD) 2021

Résumé partiel
Climate change, including global temperature rise, is one of the greatest threats facing humanity and the planet. The response of the collective human population to reduce greenhouse gas emissions, the driver of this change, has been far from adequate. To this end, methods of geoengineering the climate have been proposed, ranging from removal of carbon dioxide presently in the atmosphere (including Carbon Capture and Storage and Direct Air Capture) to methods of adjusting the amount of incoming solar radiation reaching the troposphere. Solar geoengineering (SG), also known as solar radiation management (SRM), is a proposed method of geoengineering which reflects a portion of incoming solar radiation back into space to slow or reverse global temperature rise. However, whilst simulations suggest that SG may be able to halt global mean temperature changes, it will not be able to counteract all aspects of climate change which threaten both society and ecosystems. One particularly well-known effect of current SG modelling experiments is that, when designed to offset a specific temperature rise under greenhouse gas forcing, precipitation values would be excessively offset and decrease below the baseline, reducing the overall intensity of the global hydrological cycle. A global-scale assessment is urgently needed to quantify the risks and opportunities SG poses to global water resources.

This project has examined how water resources (including drought and water scarcity) could be affected across the globe through deployment of SG. Throughout this work, the Geoengineering Large Ensemble Project (GLENS) modelling has been used as the scenario of SG ; which aimed to reduce some of the negative outcomes of previous SG modelling results, including the negative changes in precipitation. Runoff directly output from the GLENS modelling was compared to simulated runoff generated by the Global Hydrology Model (GHM) Mac-PDM.17 using climate forcing from GLENS, in order to gain some understanding of intra-model variability. Aspects of both the hazard and risk solar geoengineering may pose, contrasted against those seen under unmitigated climate change, were examined through consideration of drought and water scarcity projections across the globe. The findings of this research help answer policy-relevant research questions such as : which parts of the globe may benefit/suffer from SG ; which regions may be better off with global warming than with a cooler climate achieved by SG ; and how long may it take for such changes to occur ; all within the context of global water resources.

Mots clés  : climate change, geoengineering, solar radiation management, water resources

Présentation

Page publiée le 19 janvier 2023