On solar geoengineering and climate uncertainty

Journal Article · Fri Aug 14 00:00:00 EDT 2015 · Geophysical Research Letters

DOI:https://doi.org/10.1002/2015GL065391· OSTI ID:1229971

MacMartin, Douglas G. ^[1]; Kravitz, Benjamin S. ^[2]; Rasch, Philip J. ^[2]

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1. California Inst. of Technology (CalTech), Pasadena, CA (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Uncertainty in the climate system response has been raised as a concern regarding solar geoengineering. Here we show that model projections of regional climate change outcomes may have greater agreement under solar geoengineering than with CO₂ alone. We explore the effects of geoengineering on one source of climate system uncertainty by evaluating the inter-model spread across 12 climate models participating in the Geoengineering Model Intercomparison project (GeoMIP). The model spread in regional temperature and precipitation changes is reduced with CO₂ and a solar reduction, in comparison to the case with increased CO₂ alone. That is, the intermodel spread in predictions of climate change and the model spread in the response to solar geoengineering are not additive but rather partially cancel. Furthermore, differences in efficacy explain most of the differences between models in their temperature response to an increase in CO₂ that is offset by a solar reduction. Lastly, these conclusions are important for clarifying geoengineering risks.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE; Battelle Memorial Inst.
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1229971
• Report Number(s): PNNL-SA-110250; 400403809
• Journal Information: Geophysical Research Letters, Vol. 42, Issue 17; ISSN 0094-8276
• Publisher: American Geophysical Union
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
14 SOLAR ENERGY
geoengineering
uncertainty
models
GeoMIP