Unanticipated Side Effects of Stratospheric Albedo Modification Proposals Due to Aerosol Composition and Phase


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Date

2019

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

The Earth has now warmed ~1.0 °C since the period 1850–1900, due in large part to the anthropogenic addition of greenhouse gases to the atmosphere. Most strategies to address this warming have called for a reduction of emissions and, often, accompanying removal of greenhouse gases. Other proposals suggest masking the increased radiative forcing by an increase in particles and/or clouds to increase scattering of incoming solar radiation. Two related recent proposals have suggested addition of calcite particles to the stratosphere, which one model suggests may enhance ozone. Here we show that the interaction of calcite with acidic materials in the stratosphere results in a more complex aerosol than has been previously considered, including aqueous and hydrate phases that can lead to ozone loss. Our study suggests particle addition to the stratosphere could also perturb global radiative balance by affecting high altitude cloud formation and properties. Experimental and modeling results suggest particles will act as the nucleation sites for polar stratospheric cloud ice and, after sedimentation into the troposphere, impact cirrus clouds in the absence of other efficient ice nucleating particles. These results show that an overly simplistic set of assumptions regarding intentional particle emissions to the atmosphere can lead to incorrect estimates of the radiative effect and fail to identify unintended consequences.

Publication status

published

Editor

Book title

Volume

9 (1)

Pages / Article No.

18825

Publisher

Nature

Event

Edition / version

Methods

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Geographic location

Date collected

Date created

Subject

Organisational unit

03690 - Lohmann, Ulrike / Lohmann, Ulrike check_circle

Notes

Funding

166726 - Climate Engineering by Arctic Winter Cirrus Thinning: Risks and Feasibility (AWiCiT) (SNF)

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