The climate effects of increasing ocean albedo: an idealized representation of solar geoengineering

TitleThe climate effects of increasing ocean albedo: an idealized representation of solar geoengineering
Publication TypeJournal Article
Year of Publication2018
AuthorsKravitz B., Rasch PJ, Wang HL, Robock A., Gabriel C., Boucher O., Cole J.NS, Haywood J., Ji D.Y, Jones A., Lenton A, Moore J.C, Muri H., Niemeier U., Phipps S., Schmidt H., Watanabe S., Yang S.T, Yoon JH
JournalAtmospheric Chemistry and Physics
Volume18
Pagination13097-13113
Date Published2018/09
Type of ArticleArticle
ISBN Number1680-7316
Accession NumberWOS:000444458800001
Keywordsbasic evaluation; circulation; CMIP5; design; earth system model; irradiance reduction; Meteorology & Atmospheric Sciences; responses
Abstract

Geoengineering, or climate intervention, describes methods of deliberately altering the climate system to offset anthropogenic climate change. As an idealized representation of near-surface solar geoengineering over the ocean, such as marine cloud brightening, this paper discusses experiment Glocean-albedo of the Geoengineering Model Intercomparison Project (GeoMIP), involving an abrupt quadrupling of the CO2 concentration and an instantaneous in-crease in ocean albedo to maintain approximate net top-of-atmosphere radiative flux balance. A total of 11 Earth system models are relatively consistent in their temperature, radiative flux, and hydrological cycle responses to this experiment. Due to the imposed forcing, air over the land surface warms by a model average of 1.14 K, while air over most of the ocean cools. Some parts of the near-surface air temperature over ocean warm due to heat transport from land to ocean. These changes generally resolve within a few years, indicating that changes in ocean heat content play at most a small role in the warming over the oceans. The hydrological cycle response is a general slowing down, with high heterogeneity in the response, particularly in the tropics. While idealized, these results have important implications for marine cloud brightening, or other methods of geoengineering involving spatially heterogeneous forcing, or other general forcings with a strong land-ocean contrast. It also reinforces previous findings that keeping top-of-atmosphere net radiative flux constant is not sufficient for preventing changes in global mean temperature.

DOI10.5194/acp-18-13097-2018
Short TitleAtmos. Chem. Phys.
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