Comparing surface and stratospheric impacts of geoengineering with different SO2 injection strategies

Journal Article · Sat Jul 27 04:00:00 EDT 2019 · Journal of Geophysical Research: Atmospheres

DOI:https://doi.org/10.1029/2019JD030329· OSTI ID:1633530

Kravitz, Benjamin S. ^[1]; MacMartin, Douglas ^[2]; Tilmes, S ^[3]; Richter, Jadwiga ^[4]; Mills, Mike ^[4]; Cheng, Wei ^[2]; Dagon, Katherine ^[5]; Glanville, Anne S. ^[6]; Lamarque, J. F. ^[6]; Simpson, Isla ^[6]; Tribbia, J. ^[7]; Vitt, Francis ^[5]

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1. BATTELLE (PACIFIC NW LAB)
2. Cornell University
3. National Center for Atmospheric Research, PO Box 3000-80307,
4. University Corporation for Atmospheric Research
5. NCAR
6. National Center for Atmospheric Research
7. National Center for Atmospheric Research, Boulder, CO

Geoengineering with stratospheric sulfate aerosols can, to some extent, be designed to achieve different climate objectives. Here we use the the state-of-the-art Community Earth System Model, version 1, with the Whole Atmosphere Community Climate Model as its atmospheric component (CESM1(WACCM)), to compare surface climate and stratospheric effects of two geoengineering strategies. In one, SO2 is injected into the tropical lower stratosphere at the equator to keep global mean temperature nearly constant under an RCP8.5 scenario, as has been commonly simulated in previous studies. In another, the Geoengineering Large Ensemble (GLENS), SO2 is injected into the lower stratosphere at four different locations (30°N/S and 15°N/S) to keep global mean temperature, the interhemispheric temperature gradient, and the equator-to-pole temperature gradient nearly unchanged. Both simulations are effective at offsetting changes in global mean temperature and the interhemispheric temperature gradient that result from increased greenhouse gases, but only GLENS offsets changes in the equator-to-pole temperature gradient. GLENS results in a more even aerosol distribution, whereas equatorial injection tends to result in an aerosol peak in the tropics. Many other aspects of surface climate changes, including precipitation and sea ice coverage, also show reduced changes in GLENS as compared to equatorial injection. Stratospheric changes, including heating, circulation, and effects on the quasi-biennial oscillation are greatly reduced in GLENS as compared to equatorial injection.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1633530
• Report Number(s): PNNL-SA-141301
• Journal Information: Journal of Geophysical Research: Atmospheres, Journal Name: Journal of Geophysical Research: Atmospheres Journal Issue: 14 Vol. 124
• Country of Publication: United States
• Language: English