Innovators at work and in the classroom
Breaking the Taboo
A physicist brings talk of climate engineering into the mainstream.
By Sarah Khan
Mirrors in space, man-made clouds, and blotting out the sun with sulfur. Such engineering schemes to reverse global warming are only now entering public policy discussions as evidence mounts on the pace and impact of climate change. But to David Keith, they’re an old story. Over 20 years of studying solar radiation management (SRM), the Harvard applied physicist has argued that while such methods seem extreme, they may someday be necessary. What’s missing is more basic research to give policymakers and the public a better understanding of the risks and benefits, he says.
Dubbed a hero of the environment by Time in 2009, Keith has published more than 25 papers on how to introduce SRM and other forms of geoengineering to the public and policymakers. Besides his academic pursuits, he co-manages Bill Gates’s Fund for Innovative Climate and Energy Research (FICER) and has founded a start-up in Calgary, Canada, called Carbon Engineering, which is working to build an industrial-scale plant that could capture and reuse atmospheric carbon dioxide.
SRM, Keith’s main area of concentration, involves changing the Earth’s reflectivity to redirect sunlight back into space. Ordinarily those rays get caught in the atmosphere and, combined with greenhouse gases like carbon dioxide, help to raise global temperatures. According to a 2009 Royal Society report, “A reduction of solar input by about two percent can balance the effect on global mean temperature of a doubling of carbon dioxide.”
Giant space mirrors might be the most literal interpretation of SRM. Other possible solutions are artificially enhancing clouds to be brighter and thus more reflective, or releasing aerosols such as sulfur into the upper atmosphere to dim and, as a result, cool the planet.
One of Keith’s first papers was the 1992 “A Serious Look at Geoengineering,” in which he and his adviser at the time wanted to show there was “a need to examine geoengineering options more systematically.” At that time, while there was a lot of literature on such techniques, “no systematic research program had emerged,” according to the paper.
For decades, the subject was off the table for policymakers. “Basically, there had been a taboo against talking about [SRM] because if we did, then countries would stop getting serious about cutting emissions in other ways,” he says. Keith makes an analogy: seat belts in cars. True, they can encourage drivers to feel more protected and become more reckless, but they’re a precautionary measure that saves lives.
“For almost any risk, people’s behavior tends to shift,” Keith says. “That’s not an argument for why we should take those things off the market.”
Even today, there are no formal programs to address SRM and little federal money going to research, Keith says.
Researchers from the United States and a handful of other countries have conducted modeling experiments and some small-scale tests. But so far, studies have been confined to the academic realm. Larger scale experiments have been inhibited by concerns about what SRM could do to ecosystems, the ozone layer, and human health. In Keith’s view, that creates a Catch-22 situation: The current lack of large-scale tests makes it difficult to understand the environmental effects of SRM.
Keith sees signs of change in public awareness. He recently co-authored a study with 3,105 U.S., Canadian, and U.K. participants, revealing that about 45 percent were familiar with the term climate engineering. Those who supported SRM research were optimistic and interested in potential benefits, while opposition generally came from a feeling that nature should be left alone. The same study showed that from 2000 to 2010, media coverage and the numbers of academic papers on SRM have grown dramatically.
But as carbon dioxide concentrations in the atmosphere hit new highs, Keith worries that time is running out to prepare for what may be needed in coming years. “Almost every country in the world believes we should be doing more,” he says. “Why aren’t we?”
Sarah Khan is assistant editor of Prism.
Image Courtesy of Harvard University/Thinkstock