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"Smoke and Mirrors: Is Geoengineering a Solution to Global Warming?" with Alan Robock, Department of Environmental Sciences, Rutgers University
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 ozone depletion and regional hydrologic responses. In this talk, I describe different proposed geoengineering designs, and then show climate model calculations that evaluate both their efficacy and their possible adverse consequences. No such systems to conduct geoengineering now exist, but a comparison of different proposed stratospheric injection schemes, using airplanes, balloons, and artillery, shows that using airplanes to put sulfur gases into the stratosphere would not be expensive. Nevertheless, it would be very difficult to create stratospheric sulfate particles with a desirable size distribution. Our GeoMIP project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, is ongoing, but has already shown that temperature and precipitation responses would be uneven globally.
If there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling, stopping melting of the ice caps, and increasing the uptake of CO2 by plants. But there are at least 26 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 may reduce the current drive toward reducing greenhouse gas emissions, there are concerns about commercial or military control, and it may seriously degrade terrestrial astronomy and satellite remote sensing. Global efforts to reduce anthropogenic emissions and to adapt to climate change are a much better way to channel our resources to address anthropogenic global warming.
ABOUT THE LECTURE SERIES:
Solar geoengineering is the concept of deliberately cooling the Earth by reflecting a small amount of inbound sunlight back into space. It is the only currently known method for reducing temperatures in the short term (years to decades), and therefore has the potential to reduce many of the worst impacts of global warming. But what would be the side effects, both physical and socio-political? How would it work and who gets to decide if it is deployed? Does humanity have the wisdom and the institutions to govern the development of such a powerful technology in this messy, multi-polar world?
This seminar series, held jointly by the Harvard University Center for the Environment (HUCE) and MIT’s Joint Program on the Science and Policy of Global Change, will explore the science, technology, governance and ethics of solar geoengineering. In bringing together international experts, participants will learn some of the greatest challenges and hear opinions on how this technology could and should be managed.