Optimal sunshade configurations for space-based geoengineering near the Sun-Earth L1 point

Sánchez, J.-P. and McInnes, C. R. (2015) Optimal sunshade configurations for space-based geoengineering near the Sun-Earth L1 point. PLoS ONE, 10(8), e0136648. (doi:10.1371/journal.pone.0136648) (PMID:26309047) (PMCID:PMC4550401)

Sánchez, J.-P. and McInnes, C. R. (2015) Optimal sunshade configurations for space-based geoengineering near the Sun-Earth L1 point. PLoS ONE, 10(8), e0136648. (doi:10.1371/journal.pone.0136648) (PMID:26309047) (PMCID:PMC4550401)

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Abstract

Within the context of anthropogenic climate change, but also considering the Earth’s natural climate variability, this paper explores the speculative possibility of large-scale active control of the Earth’s radiative forcing. In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient. Large occulting structures could potentially offset all of the global mean temperature increase due to greenhouse gas emissions. This paper investigates optimal configurations of orbiting occulting disks that not only offset a global temperature increase, but also mitigate regional differences such as latitudinal and seasonal difference of monthly mean temperature. A globally resolved energy balance model is used to provide insights into the coupling between the motion of the occulting disks and the Earth’s climate. This allows us to revise previous studies, but also, for the first time, to search for families of orbits that improve the efficiency of occulting disks at offsetting climate change on both global and regional scales. Although natural orbits exist near the L1 equilibrium point, their period does not match that required for geoengineering purposes, thus forced orbits were designed that require small changes to the disk attitude in order to control its motion. Finally, configurations of two occulting disks are presented which provide the same shading area as previously published studies, but achieve reductions of residual latitudinal and seasonal temperature changes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McInnes, Professor Colin
Authors: Sánchez, J.-P., and McInnes, C. R.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:PLoS ONE
Publisher:Public Library of Science
ISSN:1932-6203
ISSN (Online):1932-6203
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in PLoS ONE 10(8):e0136648
Publisher Policy:Reproduced under a Creative Commons License

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