Warming up to solar geoengineering

Driving the news: A report released today by the National Academies of Sciences (NAS) details recommendations for conducting, funding and governing research on solar geoengineering.

• The authors say most climate research resources should still be steered toward mitigation and adaptation, but they call for $100 million to $200 million to be devoted to studying solar geoengineering over the next five years. (About $10 million is spent worldwide today, says David Keith, a physicist and faculty director for the Harvard solar geoengineering program.)
• The report's authors also call for a comprehensive research program that would involve all federal agencies conducting climate research.
• The research program would seek to answer not only if solar geoengineering programs can be feasibly deployed, but also address the thorny question of whether they should be once more is known about the technologies.

How it works: Solar geoengineering involves injecting aerosols into the stratosphere or brightening clouds over the world's oceans with the aim of reflecting sunlight and lowering global temperatures.

Where it stands: A slew of solar engineering concepts is on the drawing board — from flying balloons into the stratosphere to disperse aerosols to spraying sulfur dioxide from high-flying airplanes to using ships that help to evaporate saltwater into tiny droplets that brighten marine clouds.

• But the technology doesn't exist yet, says Alan Robock, a climate scientist at Rutgers University who models the potential impact of geoengineering on the climate.
• Right now, a research program affiliated with Harvard University is awaiting permission to test a high-flying balloon over Sweden, in a limited real-world experiment of a geoengineering tool. That small-scale experiment has encountered opposition from environmentalists, demonstrating the difficulties that further experiments (let alone deployment) may encounter.
• Whether these concepts are possible or would work and under what conditions are still open questions, Robock says, and answering them is necessary in case we want to use the technology in the future.

Yes, but: The NAS report recommends funding modeling, theory and governance of solar geoengineering over the next five years. It specifically cautions against a move to develop and deploy such technologies.

• Robock and other researchers argue money should be spent on building and testing ships and unmanned planes that underpin deploying the technology.
• "People worry building the technology is a slippery slope to it being deployed," Robock says. "It is more of a sticky slope. The more we look into it, the more risks we may discover and reasons not to do it. Doing research doesn’t necessarily lead to deployment — it might lessen the chances of it happening."

The pushback: Some of the opposition to solar geoengineering research stems from concerns that it could distract from efforts to rein in emissions.

• “I think the fear of many is that it will be exploited by interests that oppose emissions cuts like fossil fuel companies,” says Keith. He sees solar geoengineering technologies as being where climate adaptation was just a few years ago, when some climate advocates did not want to discuss it due to the fear it would distract from emissions cuts.
• Making emissions cuts are still the main focus of addressing global warming, said Chris Field, a climate scientist at Stanford University and lead author of the NAS report. “There’s no sense in which solar engineering is an alternative to decarbonization,” he said.

What they're saying: The authors also emphasize the need for governance — transparency, reporting and public input — "mechanisms of accountability which are critical in a field that is rife with conspiracy theories and misinformation," says Stewart Patrick of the Council on Foreign Relations. 

• "They are right to call for a sober assessment of the feasibility of solar geoengineering technologies and to hold out the prospect that geoengineering could ultimately become a third pillar of global climate action," he says.
• "Without adequate rules, geoengineering will create massive, unintended consequences, deepen geopolitical rivalries and hasten the world’s division into climate winners and losers," Patrick wrote this week.

What to watch: The report also calls for researchers, governments and citizens in the Southern Hemisphere to be engaged in discussions and research.

• "It will impact the one global atmosphere, so it will impact everybody," says Janos Pasztor, executive director of the Carnegie Climate Governance Initiative.

The bottom line: “The underlying decision is, should humans do this or not?” Keith said. “Learn, then decide, is the right lesson from my point of view.”