House science committee explores climate engineering proposals

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Related Documents Industry Document "Testimony of Alan Robock" presented on 11/5/2009 Industry Document "Historical Perspectives on “Fixing the Sky”" presented on 11/5/2009 Industry Document "Testimony by John Shepherd" presented on 11/5/2009 Industry Document "Geoengineering: Assessing the Implications of Large-Scale Climate Intervention" presented on 11/5/2009

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While fraught with great uncertainty, climate engineering proposals aimed at removing greenhouse gases from the Earth's atmosphere and reflecting sunlight received serious consideration at a House Science and Technology Committee hearing Nov. 5.

"Geoengineering carries with it a tremendous range of uncertainties, ethical and political concerns, and the potential for catastrophic environmental side-effects. But we are faced with the stark reality that the climate is changing, and the onset of impacts may outpace the world's political and economic ability to avoid them," committee Chairman Bart Gordon, D-Tenn., said in opening the hearing to explore the implication of large-scale climate interventions.

"I believe this hearing marks the first time that a congressional committee has undertaken a serious review of proposals for climate engineering. That is not surprising," Gordon said, adding that it is a complex and controversial subject that has had little debate in the United States. "At its best, geoengineering might only buy us some time. But if we want to know the answers, we have to first ask the tough questions."

Alan Robock, professor of climatology at Rutgers University, told the committee that "aggressive mitigation" will be needed to reduce the impacts of global warming. He described two types of geoengineering proposals. The first, solar radiation management, involves producing a stratospheric cloud or making low clouds over the ocean brighter. The second is carbon capture and sequestration by biological or chemical means over the land or oceans.

Robock proposed the idea of emulating explosive volcanic eruptions by attempting to produce a stratospheric cloud that would reflect some incoming sunlight to shade and cool the planet to counteract global warming. Arguing that ongoing climate change will have broad impacts on society, he said that if geoengineering is ever used, "it should be as a short-term emergency measure, as a supplement to, and not as a substitute for, mitigation and adaptation. And we are not ready to implement geoengineering now."

The question of whether geoengineering could ever help to address global warming cannot be answered at this time, Robock told the committee. While it is possible to identify potential benefits and risks of stratospheric geoengineering, he argued that "a vigorous research program is needed to quantify" the risks and benefits of different options.

A research program is needed to "evaluate various suggested schemes for producing stratospheric particles, to see whether it is practical to maintain a stratospheric cloud that would be effective at blocking sunlight," Robock concluded. "For geoengineering ever to be tested, and for monitoring future large volcanic eruptions anyway, we need to rebuild our capacity to observe particles in the stratosphere, using satellites and ground-based observations."

James Fleming, a professor and director of science, technology and society at Colby College, enumerated several problems with the idea of climate engineering, including a lack of technology, political capital and wisdom. Noting that the side effects of climate engineering are not known, he said that it poses a "moral hazard" by reducing the incentives to mitigate climate change.

In addition, climate engineering could be militarized, and based on history, "it likely would be militarized," Fleming said. He also noted that climate engineering does nothing to solve the problem of ocean acidification.

John Shepherd, a professor at the National Oceanography Centre, University of Southampton, in the United Kingdom, summarized the findings of a U.K. Royal Society study he chaired on geoengineering. He emphasized that geoengineering is neither a "magic bullet" nor an alternative to reducing global emissions of greenhouse gases. However, because cutting emissions of greenhouse gases is proving to be difficult, he said geoengineering may be useful in the future to support mitigation efforts.

"Geoengineering is very likely to be technically possible. However, there are major uncertainties and thus potential risks with all methods, concerning their effectiveness, costs, and social and environmental impacts," Shepherd said. "Much more research is needed before geoengineering methods could realistically be considered for deployment," particularly on their possible environmental and economic impacts.

Shepherd noted that methods of removing greenhouse gases from the atmosphere "address the root cause of the problem and would be generally preferred, but they only act slowly and are likely to be costly." Geoengineering also includes methods of reflecting a little sunlight. "These act quickly, and are relatively cheap, but have to be maintained so they may not be sustainable in the long term," he said.

"We do not yet have enough information, so it is too soon to pick winners, and if geoengineering is ever deployed we may need a combination of both types of method," Shepherd added. "We therefore need to commence serious research and development on several of the promising methods, as soon as possible."

While not endorsing any geoengineering activity, Gordon said that the issue is "too important for us to keep our heads in the sand. We must get ahead of geoengineering before it gets ahead of us, or worse, before we find ourselves in a climate emergency with inadequate information as to the full range of options."

Gordon plans to hold two or three hearings on the subject of climate engineering over the next eight months to explore in greater detail the science, engineering, ethical, economic and governance concerns associated with various geoengineering proposals.