INVITED ABSTRACT
Risks of Using Stratospheric Aerosols for Geoengineering

ALAN ROBOCK

Rutgers University

     Abstract Number: 342
     Last modified: May 8, 2010

Abstract
In response to the global warming problem, there has been a recent renewed interest in geoengineering “solutions” involving “solar radiation management” by injecting particles into the stratosphere, brightening clouds, or blocking sunlight with satellites between the Sun and Earth. While volcanic eruptions have been suggested as innocuous examples of stratospheric aerosols cooling the planet, the volcano analog actually argues against geoengineering because of regional hydrologic responses, ozone depletion, and reduction of solar energy. Climate model simulations show that if there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling, stop melting of the ice caps, and increase the uptake of CO2 by plants. But there are 20 reasons why geoengineering may be a bad idea. These include disruption of the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people; ozone depletion; no more blue skies; reduction of solar power; and rapid global warming if it stops. Furthermore, the prospect of geoengineering working would reduce the current drive toward reducing greenhouse gas emissions, there are concerns about commercial or military control, and it would seriously degrade terrestrial astronomy and satellite remote sensing. Standardized climate model experiments are needed to evaluate the benefits and risks of stratospheric geoengineering, so that policy makers in the future will be able to make informed decisions about whether to ever deploy geoengineering in global warming emergency. But without any governance standards for in situ testing, these experiments should remain indoors between consenting adults.