The purpose of this hearing is to assess the status of geoengineering research in the United States, while also exploring potential technologies and innovation.
Date: Wednesday, November 8, 2017 - 10:00am
Location: 2318 Rayburn House Office Building, Washington DC 20515
Subcommittee on Energy (115th Congress)
Subcommittee on Environment (115th Congress) 
- Ranking Member Suzanne Bonamici (D-OR) of the Subcommittee on Environment
- Ranking Member Marc Veasey (D-TX) of the Subcommittee on Environment
- Ranking Member Eddie Bernice Johnson (D-TX)
- Dr. Phil Rasch, chief scientist for climate science, Laboratory Fellow, Pacific Northwest National Laboratory
- Dr. Joseph Majkut, director of climate policy, Niskanen Center
- Dr. Douglas MacMartin, senior research associate, Cornell University
- Ms. Kelly Wanser, principal director, Marine Cloud Brightening Project, Joint Institute for the Study of the Atmosphere and Ocean, University of Washington
Major Points 
- Research on geoengineering strategies is still in its infancy, but suggests they may represent a promising complement to other responses to climate change. For example, Sunlight Reduction Method (SRM) technologies appear to have the potential to offset, delay, or slow some of the warming driven by greenhouse gas emissions, and thus might help “buy time” for other mitigation and adaptation measures to be put in place.
- However, it isn’t yet clear whether geoengineering should be part of solution strategies to address observed and anticipated changes in the climate system—we simply do not yet know enough about the potential benefits or risks that might be associated with large-scale deployment of geoengineering technologies.
- A comprehensive research program—including modeling, laboratory studies, small-scale field experiments, and technology development—is needed to better understand the potential role that geoengineering strategies could take in the broader context of other climate response options. My written testimony contains a number of suggestions for components of such a research program, and examples in areas where progress could be made.
- Even if they are determined to be viable, geoengineering strategies won’t be a magic bullet that eliminates the need for emissions reductions or adaptation measures. While geoengineering technologies could be effective at offsetting some of the effects of climate change, they will not compensate for all of them, and may introduce their own problems.
- Similarly, geoengineering will not be a quick fix—sustained investment and work will be required over many years, possibly decades, before we know what, if any, is the right path forward on geoengineering efforts.
- If SRM technologies were chosen as a measure to address greenhouse gas warming, they would need to be used for as long as excess greenhouse gases remain in the atmosphere, requiring long term use to remain effective.
- Marine cloud brightening and stratospheric aerosols are SRM strategies have some common features but they are different in some important ways. Each potential geoengineering strategy has its own potential benefits, risks and costs, and each needs to be carefully evaluated.
- Small-scale field experiments are needed to develop a better process-level understanding of the potential effectiveness of SRM. While the scale of these field experiments would be too small to influence regional or global climate, they would provide opportunities to develop a review and governance strategy to ensure the transparency and safety of such experiments.
- Progress in understanding SRM strategies can also be of great benefit to general climate science. For example, smallscale field studies addressing geoengineering issues could also answer some long-standing, key scientific questions regarding the influence of atmospheric particles on cloud brightness and precipitation.
- I believe it is time for a coherent and goal-oriented geoengineering research program that complements ongoing research in atmospheric processes and Earth System science, and focuses on a defined set of objectives targeting better understanding of the effectiveness and potential risks associated with specific geoengineering technologies.
- It is essential that any geoengineering research program integrate consideration of societal needs, transparency, and governance issues with a program for making progress in the physical and natural sciences. It should also work closely with existing climate science research activities across the federal government, complementing these activities as an addition to these programs.
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