WASHINGTON -- A pair of reports from one of the country's leading scientific bodies suggests that while geoengineering should not be treated as the solution to climate change, it merits further investigation.
The National Academy of Sciences released the reports on geoengineering, or deliberately changing the earth's atmosphere in order to address climate change, on Tuesday. They review the current science on methods to remove carbon removal from the atmosphere and examine measures that could be used to enhance the reflection of sunlight off the earth, known as albedo modification.
Taken together, the reports suggest that more research and even some testing of these types of climate intervention methods are needed to understand their potential benefits and drawbacks, as well as the governance challenges if some countries or actors decide to take them on unilaterally.
"It is the committee’s sincere hope that these topics will receive the attention and investment commensurate with their importance to addressing the coming potential climate crises," Marcia McNutt, chair of the Committee on Geoengineering Climate, wrote in the introduction to the reports. "By helping to bring light to this topic area, carbon dioxide removal technologies could become one more viable strategy for addressing climate change, and leaders will be far more knowledgeable about the consequences of albedo modification approaches before they face a decision whether or not to use them."
A variety of types of geoengineering have been discussed, but few have been tested at scale in the real world. One method of removing carbon from the atmosphere, ocean iron fertilization, would pose environmental risks and would need to be investigated further before it could be pursued. The risks of other techniques, which involve pulling carbon out of the air and storing it underground, are lower and better understood, but many are limited by slow speed and high costs. The panel recommended more research and development investment in these areas.
The risks of modifying the earth's albedo, which can be done by emitting sunlight-reflecting aerosols into the the atmosphere or brightening clouds to make them more reflective, are much less clear. The panel advised against undertaking such efforts at this time, but advised creating a research program that could improve understanding in the field.
The reports emphasize the need to cut the emission of climate-warming greenhouse gases. But, the researchers conclude, "if society ultimately decides to intervene in Earth's climate, the Committee most strongly recommends any such actions be informed by a far more substantive body of scientific research--encompassing climate science and economic, political, ethical, and other dimensions--than is present now."
The findings are notable, especially since many in the environmental world have long considered geoengineering to be a last resort, arguing that even considering it might detract from efforts to cut pollution. On Tuesday, even some environmental groups praised the report.
“There’s absolutely no substitute for slashing fossil fuel emissions in order to prevent catastrophic disruption of the Earth’s climate. But it’s prudent to do research into geoengineering because, for instance, improved carbon dioxide-removal techniques could help reduce such dangerous pollution," Rhea Suh, president of the Natural Resources Defense Council, said in a statement. "We also need research because manipulating solar radiation is risky and we must increase our understanding of those risks.”
The report, said Simon Nicholson, an assistant professor of international relations at American University and the co-director of the Forum for Climate Engineering Assessment, "makes clear, loudly and often, that climate engineering is no substitute for aggressive action to reduce emissions of greenhouse gases. That's a very important and welcome move."
But Nicholson emphasized the need for caution going forward.
"It makes far more sense," he said, "to keep carbon dioxide out of the atmosphere in the first place than it does to put faith in speculative schemes to draw down carbon once it has already been emitted."