NEWSFOCUS Sun blocker. Serious geoengineering research is long past due, says physicist David Keith. ing infl uential academic papers, the Canadian scientist has become geoengineering’s public face, delivering sold-out lectures and vivid quotes to the media. He’s also become some- thing of a power broker, advising one of the world’s richest men on climate issues and doling out some $6 million of Bill Gates’s money to convene meetings and spur new research. And 2 years ago, Keith gained a high-profi le perch for promoting his views, moving from the University of Calgary in Canada to Harvard University. Now, Keith wants to bring geoengi- neering out of the ivory tower and into the stratosphere. He and a partner at Harvard are proposing one of the world’s first geo- engineering fi eld experiments, using a high- altitude balloon to release sun-blocking vapors into the atmosphere. And this month, Keith is releasing a book, A Case for Climate Engineering, in which he argues that “the potential upsides of geoengineering” demand on October 28, 2013 greater research. Such studies “may show that these technologies will not work,” he writes. “Yet the sooner we fi nd this out the better.” It’s an audacious agenda for a scientist col- leagues describe as equal parts thoughtful, CLIMATE CHANGE unorthodox, and headstrong. And he faces a myriad of obstacles, including a lack of orga- nized government support and fi erce opposi- Dr. Cool tion from critics—one of whom calls Keith’s www.sciencemag.org sun-blocking ideas “barking mad.” He’s even gotten death threats. David Keith has helped usher geoengineering into the mainstream. Actually testing Further complicating matters is Keith’s a way to cool the planet is his next big challenge ownership stake in a company that is pursuing a different fl avor of geoengineering—sucking David Keith was a 26-year-old graduate stu- Few others, however, paid much attention. carbon dioxide out of the air. That has raised dent in experimental physics when he first And for the next 15 years, discussions of geo- questions about fi nancial confl icts. And some Downloaded from heard of geoengineering, the concept of inten- engineering drifted between the fringe of aca- wonder whether Keith has the diplomatic tionally tinkering with Earth’s climate system demic research and science fi ction. Still, as savvy to win over opponents. “David does in order to counteract global warming. It was Keith built a career as a specialist on energy not suffer fools gladly,” says David Layzell, 1989, and some of his colleagues at the Mas- and climate issues, he periodically published Keith’s former boss at the University of Cal- sachusetts Institute of Technology (MIT) in papers suggesting that scientists needed to gary. “Everybody respects him—or is a little Cambridge considered the idea distasteful, take geoengineering seriously. terrifi ed of him.” Keith recalls. Discussing possible experi- In the past 5 years, they have. As carbon ments was “a de facto taboo” in the fi eld. dioxide continues to build up in the atmo- A polymath That didn’t deter Keith, who saw the dearth sphere, the U.S. National Academies, the Keith grew up in Ottawa, where his father of interest as a professional opportunity. Three United Kingdom’s Royal Society, and the and stepmother, both wildlife biologists, years later, he published his fi rst paper on the American Geophysical Union have all issued taught him how to stuff birds, enjoy the out- topic. Geoengineering needed a “systematic calls to explore expanding research into tech- doors, and work with his hands. After earn- research program,” Keith and a co-author con- nological fi xes. The number of scientists pub- ing a physics degree at the University of cluded after analyzing the few existing stud- lishing on geoengineering is growing, as are Toronto, Keith headed to MIT, where “he ies of possible approaches, including sucking citations of their work by infl uential groups, was an incredible hot shot,” recalls Harvard’s carbon dioxide out of the atmosphere with such as the Intergovernmental Panel on Cli- William Clark, an early mentor. machines and releasing particles into the sky mate Change (IPCC). But Keith was troubled by the military to block sunlight. Such exotic technologies, Keith has ridden geoengineering’s shift applications of his physics research and they argued, had the “potential to mitigate cat- from the fringe toward the mainstream—and instead drifted toward the burgeoning fi eld of CREDIT: ELIZA GRINNELL/HARVARD SEAS ELIZA GRINNELL/HARVARD CREDIT: astrophic climate change.” has helped catalyze it. In addition to publish- climate and energy research. After he earned www.sciencemag.org SCIENCE VOL 342 18 OCTOBER 2013 307 Published by AAAS NEWSFOCUS Aiming high. A proposed experiment would use a balloon to release sulfuric acid vapor (A) and then measure its effect on ozone chemistry in successive passes (B). his doctorate in 1991, his eclectic interests Keith’s persuasiveness came with a con- holds appointments in the schools of engi- led to an array of jobs over the next decade: fidence that could be alienating, however. neering and government, has brought him policy analysis at Carnegie Mellon University “David is usually right, and he has a high close to science and policy heavyweights— in Pittsburgh, Pennsylvania; climate model- degree of confi dence that he’s right,” says geo- and students who go on to become power- ing at the National Center for Atmospheric chemist Ken Caldeira of the Carnegie Institu- ful policymakers around the world. It’s also Research in Boulder, Colorado; building tion for Science in Palo Alto, California. And an opportunity to team with some of the atmospheric instruments at Harvard; and even that can be “off-putting to some people,” says nation’s top atmospheric scientists, and ramp a stint in environmental ethics at the Univer- Jane Long, an energy scientist at the Univer- up efforts on one of Keith’s priorities, devel- sity of Montana in Missoula. “A lot of rock sity of California, Berkeley, who nonetheless oping rules for governing geoengineering climbing, too,” Keith says. commends Keith’s “strong ability to get peo- research. And Cambridge offers a bully pul- Along the way, he published a num- ple to see his point of view, while seeing mul- pit for injecting the topic into international ber of provocative papers, including a 2001 tiple confl icting points of view.” discussions. Or, as Keith put it in a 2007 TED Science publication that questioned the In Calgary, Keith’s willingness to speak talk: “We need a broader debate … not just a potential of wind power to replace fossil his mind sometimes complicated his rela- few oddballs like me.” fuels, and analyses of hydrogen fuel, natural tionships with industry. A few fi rms refused gas, and the then-controversial concept of to partner with the university after Keith chal- A low-dose supplement carbon capture and storage (CCS): capturing lenged Alberta’s efforts to mine its oil sands, Keith hopes to jump-start that debate with A carbon dioxide from industrial smokestacks for instance. But Keith was becoming an Case for Climate Engineering. In 112 pages and pumping it underground. entrepreneur himself, launching Carbon Engi- of authoritative prose, he largely eschews fi g- Geoengineering continued to fascinate neering, a startup aiming to build machines to ures and technical terms in a bid to reach a him, Keith says, because it provided a new remove carbon dioxide from the atmosphere, lay audience. He begins by casting the cli- look at humanity’s relationship with nature, in 2009. One of its investors is Microsoft co- mate challenge in stark terms: Past emissions which he valued personally as an outdoors- founder Bill Gates, for whom Keith has served have already committed Earth to substantial man. Geoengineering “encourages us to as an informal energy adviser since 2006. warming, he warns; even aggressive emis- rethink some of our root assumptions about The amount of Gates’s investment in the sions cuts—if they ever materialize—can the means and ends of climate policy,” he company is undisclosed, but the mogul has only partly reduce climate risks. But geo- writes in his book. also provided roughly $6 million to the infor- engineering techniques could relatively By 2004, when the University of Calgary mal Fund for Innovative Climate and Energy quickly “cut the average rate of global warm- recruited Keith from Carnegie Mellon, he was Research, managed by Keith and Caldeira. ing in half for the next half-century,” he argues. considered a go-to voice on geoengineering, Since 2007, the fund has supported more In particular, Keith focuses on one tech- and he began building bridges with business. than a dozen research projects, most on geo- nique: releasing sulfuric acid vapor high in In 2007, he joined with four top executives in engineering. It also helps fund a weeklong the stratosphere, where it would scatter sun- Alberta’s powerful energy industry to write summer school on the topic, now in its fi fth light away from Earth’s surface. The approach a report touting the potential of CCS to curb year, which brings together physical and mimics the global cooling effect of large vol- carbon emissions. It drew darts from envi- social scientists. The networking opportunity canic eruptions, which spew sulfates into the ronmentalists, but led to a pledge to invest “shows David’s great value” as a scientist and stratosphere. But Keith envisions a “slow SCIENCE $3 billion in CCS technology by the Alberta organizer, says Benjamin Kravitz, a climate ramp scenario,” gradually adding sulfur over and Canadian governments, which had re- modeler at Pacifi c Northwest National Labo- decades to counteract about one-half the quested the study.