HR: 14:30h
AN: U23A-03 INVITED     [Abstracts]
TI: Arctic Stratospheric Geoengineering with Spring or Summer Injections
AU: * Robock, A
EM: robock@envsci.rutgers.edu
AF: Rutgers University, Department of Environmental Sciences, 14 College Farm Road, New Brunswick, NJ 08901, United States
AU: Marquardt, A B
EM: abmarq18@eden.rutgers.edu
AF: Rutgers University, Department of Environmental Sciences, 14 College Farm Road, New Brunswick, NJ 08901, United States
AU: Kravitz, B
EM: benkravitz@envsci.rutgers.edu
AF: Rutgers University, Department of Environmental Sciences, 14 College Farm Road, New Brunswick, NJ 08901, United States
AU: Stenchikov, G L
EM: gera@envsci.rutgers.edu
AF: Rutgers University, Department of Environmental Sciences, 14 College Farm Road, New Brunswick, NJ 08901, United States
AB: Placing aerosols into the stratosphere to block out sunlight and cool Earth has been suggested to counteract global warming. Previous computer simulations of schemes to put aerosols continuously into the Arctic or tropical stratospheres produced Northern Hemisphere or global cooling, but a reduction of Asian and African summer monsoon precipitation, which would threaten the food supply for billions of people. If society found it desirable to temporarily cool the Arctic to preserve summer sea ice and Greenland while mitigation and carbon capture and sequestration measures are rapidly implemented, it would not be necessary to place aerosols into the winter stratosphere, as there would be no sunlight to block. The e-folding lifetime for Arctic stratospheric aerosols is only about three months. Here we present the results of new simulations injecting aerosol precursors only in spring or summer, to investigate whether it would be possible to cool the Arctic with a smaller impact on the monsoon than for a continuous cloud. At the same time, the cost of injection of aerosols would be much smaller than for continuous injection. We simulated the injection of 0.75 Tg SO₂ per year at 68°N during 1-month and 3-month periods starting on April 1 for 20 years. We also simulated the August, 2008 eruption of the Kasatochi volcano using 1.5 Tg and 3 Tg SO₂ injections, which while a one time injection, can also inform us about geoengineering. Preliminary results suggest that by putting enough aerosols into the summer Arctic stratosphere to reduce sunlight and cool the planet cannot avoid summer monsoon impacts.
DE: 0394 Instruments and techniques
DE: 1620 Climate dynamics (0429, 3309)
DE: 1694 Instruments and techniques
DE: 3362 Stratosphere/troposphere interactions
SC: Union [U]
MN: 2009 Joint Assembly