Premium
On solar geoengineering and climate uncertainty
Author(s) -
MacMartin Douglas G.,
Kravitz Ben,
Rasch Philip J.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065391
Subject(s) - geoengineering , environmental science , radiative forcing , climate change , coupled model intercomparison project , climatology , climate model , precipitation , atmospheric sciences , forcing (mathematics) , meteorology , geography , physics , geology , oceanography
Uncertain climate system response has been raised as a concern regarding solar geoengineering. We explore the effects of geoengineering on one source of climate system uncertainty by evaluating the intermodel spread across 12 climate models participating in the Geoengineering Model Intercomparison project. The model spread in simulations of climate change and the model spread in the response to solar geoengineering are not additive but rather partially cancel. That is, the model spread in regional temperature and precipitation changes is reduced with CO 2 and a solar reduction, in comparison to the case with increased CO 2 alone. Furthermore, differences between models in their efficacy (the relative global mean temperature effect of solar versus CO 2 radiative forcing) explain most of the regional differences between models in their response to an increased CO 2 concentration that is offset by a solar reduction. These conclusions are important for clarifying geoengineering risks regarding uncertainty.