Key scientific assessments have underscored the urgency of reducing emissions of carbon dioxide to help mitigate potentially negative effects of climate change; however, many countries with significant greenhouse gas emissions, including the United States, China, and India, have not committed to binding limits on emissions to date, and carbon dioxide levels continue to rise. Recently, some policymakers have raised questions about geoengineering--large-scale deliberate interventions in the earth's climate system to diminish climate change or its potential impacts--and its role in a broader strategy of mitigating and adapting to climate change. Most geoengineering proposals fall into two approaches: solar radiation management (SRM), which offset temperature increases by reflecting a small percentage of the sun's light back into space, and carbon dioxide removal (CDR), which address the root cause of climate change by removing carbon dioxide from the atmosphere. Today's testimony focuses on GAO's preliminary observations on (1) the state of the science regarding geoengineering approaches and their effects, (2) federal involvement in geoengineering activities, and (3) the views of experts and federal officials about the extent to which federal laws and international agreements apply to geoengineering. To address these issues, GAO reviewed scientific literature and interviewed federal officials and scientific and legal experts.
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