Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection

Atmospheric Chemistry and Physics. 2016;16(5):2843-2862 DOI 10.5194/acp-16-2843-2016

 

Journal Homepage

Journal Title: Atmospheric Chemistry and Physics

ISSN: 1680-7316 (Print); 1680-7324 (Online)

Publisher: Copernicus Publications

Society/Institution: European Geosciences Union (EGU)

LCC Subject Category: Science: Physics | Science: Chemistry

Country of publisher: Germany

Language of fulltext: English

Full-text formats available: PDF, XML

 

AUTHORS

A. C. Jones (College of Engineering Maths and Physical Sciences, University of Exeter, Exeter, UK)
J. M. Haywood (College of Engineering Maths and Physical Sciences, University of Exeter, Exeter, UK)
A. Jones (Met Office Hadley Centre, Exeter, UK)

EDITORIAL INFORMATION

Peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 16 weeks

 

Abstract | Full Text

In this paper, we examine the potential climatic effects of geoengineering by sulfate, black carbon and titania injection against a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate scenarios in which the top-of-the-atmosphere radiative imbalance due to rising greenhouse gas concentrations is offset by sufficient aerosol injection throughout the 2020–2100 period. We find that the global-mean temperature is effectively maintained at historical levels for the entirety of the period for all three aerosol-injection scenarios, though there is a wide range of side-effects which are discussed in detail. The most prominent conclusion is that although the BC injection rate necessary to produce an equivalent global mean temperature response is much lower, the severity of stratospheric temperature changes (> +70 °C) and precipitation impacts effectively exclude BC from being a viable option for geoengineering. Additionally, while it has been suggested that titania would be an effective particle because of its high scattering efficiency, it also efficiently absorbs solar ultraviolet radiation producing a significant stratospheric warming (> +20 °C). As injection rates and climatic impacts for titania are close to those for sulfate, there appears to be little benefit in terms of climatic influence of using titania when compared to the injection of sulfur dioxide, which has the added benefit of being well-modeled through extensive research that has been carried out on naturally occurring explosive volcanic eruptions.