Experts at AAAS Forum Explore Controversial Geoengineering Ideas for Cooling the Planet

With nations incapable so far of taking drastic steps to cut emissions of heat-trapping greenhouse gases, many scientists and policy specialists have started talking more openly about geoengineering, the deliberate manipulation of the environment to reverse the effects of climate change.

For them, geoengineering may be “a bad idea whose time has come,” said Eli Kintisch, a reporter for Science, at a AAAS forum on the topic.

Whether deploying sulfate aerosols in the stratosphere as an artificial sun shade to cool the planet or creating huge blooms of algae in the world’s oceans to suck carbon dioxide from the atmosphere, techniques once considered fanciful speculation now are being seriously debated.

Eli Kintisch

Eli Kintisch

Kintisch, who has written a new book on climate engineering, “Hack the Planet” (Wiley, 2010), was co-moderator of the 20 April forum on the science and policy implications of the topic. The event was organized by the AAAS Center for Science, Technology, and Sustainability.

Panelists agreed there are many uncertainties about any attempts to tinker with the climate. But Daniel Sarewitz, co-director of the Consortium for Science, Policy and Outcomes at Arizona State University, said the existence of “irreducible uncertainties” should not be the determinant on whether to pursue geoengineering. Science is quite good at characterizing uncertainties, he said, although reducing them will be extremely difficult, given the complex dynamics of the climate system.

“The uncertainty is going to need to be managed in a way that is politically smart, and that means inclusive discussions from a very early stage,” said Sarewitz, who is on a bipartisan National Commission on Energy Policy (NCEP) task force on geoengineering. While he emphasized that he was not speaking for the task force, Sarewitz said there does seem to be a consensus in the group that research on geoengineering would not be a “moral hazard” that diminishes the commitment to sharply and rapidly reducing emissions of greenhouse gases.

Daniel Sarewitz

Daniel Sarewitz

According to the NCEP, one of the goals of the task force is to develop a clear definition of geoengineering that policy makers can use. Most definitions include solar radiation management techniques, such as use of aerosol particles to increase Earth’s albedo, or reflectivity, and carbon dioxide removal techniques aimed at reducing the concentrations of greenhouse gases.

Blocking sunlight can, in theory, be done quite cheaply and quickly using a fleet of airplanes to deploy sulfate particles in the upper atmosphere. But scientists caution there could be unpredictable impacts of planet-wide efforts to manipulate the climate. “There will be unintended consequences,” Sarewitz said, “but there are unintended consequences about any interventions in natural and social systems.”

Michael MacCracken

Michael MacCracken

Michael MacCracken, chief scientist for climate change programs at the Climate Institute, said mitigation strategies to reduce the amount of carbon dioxide being released into the atmosphere and adaptation strategies, such as moving key business centers away from coastal areas vulnerable to rising sea levels, needs to precede any large-scale efforts to geoengineer the climate.

“Mitigation has to come first,” MacCracken said. “We have to reduce emissions.”

Mitigation can include steps such as improving energy efficiency, capturing and storing carbon dioxide at sources such as power plants, and using non-carbon energy sources. If the world were to continue producing eight to 10 billion tons of carbon emissions each year, he said, it would be largely fruitless to remove, say, 1 billion tons a year by seeding the world’s oceans with iron particles to induce carbon-ingesting algae blooms.

MacCracken, who helped organize a recent conference of 175 participants from 15 nations to discuss voluntary rules to govern research on geoengineering, said that any efforts to manipulate the climate might focus initially on seeking to reduce regional impacts rather than ambitious attempts to bring down the global average temperature by a degree or two.

The seasonal melting of sea ice in the Arctic has been accelerating, MacCracken said, and steps to induce cooling in the atmosphere over the Arctic might be the sort of limited climate-engineering that could try to reverse harmful regional impacts. Another limited option, he said, would be trying to change the track or intensity of storms that can result from climate change. He noted that the Department of Homeland Security is supporting research on mechanisms—such as seeding storm clouds with particles to induce rainfall—that could cause tropical storms and hurricanes to weaken before they reach land.

“I think if you were going to start it [geoengineering], you would start by going after some pretty focused, specific objective and then figure out which of the number of technologies that you have you might be able to apply,” MacCracken said. He cautioned that researchers still need to do much more to understand the possible impacts and worst-case scenarios involving climate engineering. “You’re really going to have to make this an international research program,” he said.

Sarewitz said governance procedures for geoengineering should evolve at the same time as the scientific research proceeds. Any institutions that attempt to tinker with the climate will need a “hard-headed focus on maintaining public trust,” he said. If there is a lack of transparency and openness, he added, “it will be extremely difficult to manage politically.”

A second panel grappled with some of the policy questions surrounding geoengineering and climate change. Lee Lane, a resident fellow at the American Enterprise Institute and co-director of the AEI Geoengineering Project, argued that it makes the best sense economically to pursue a three-pronged strategy: reduction of greenhouse gas emissions; adaptation to the impacts of global warming; and use of engineering methods to reduce solar radiation and cool the planet.

With very little chance of an effective international regime to reduce greenhouse gas emissions in the next several decades, Lane said, it is essential “to think more seriously about climate engineering.” But some of the same domestic political dynamics in democracies that make control of greenhouse gas emissions difficult also will “check or restrain any rapid movement to climate engineering,” he said.

Still, Lane mentioned steps that can help prepare the political groundwork for any future efforts to engineer the climate. He recommended that the executive branch establish an entity, separate from the White House science adviser’s office, to manage federal research and development on geoengineering.

“Before we get involved in figuring out how to manage international coordination of climate engineering, there needs to be some place in the U.S. government to think through what U.S. national interests with respect to climate engineering really are,” Lane said.

On the global scale, he called for a middle ground between unilateral action by a single nation and an effort to get universal participation in a geoengineering regime. He suggested that representatives from 10 to 15 powerful countries with adequate finances and technical capability could serve as a governing body for future efforts to engineer the climate.

“We really need a regime that will have the best chance of going forward responsibly and carefully,” Lane said. With too many players, he said, the process can easily bog down, much as has happened in the long international effort to mandate reductions in greenhouse gases.

Juliet Eilperin

Juliet Eilperin

It remains unclear whether a global effort on climate engineering will ever occur. In the United States, the realities of dealing with climate change in a fractured political environment suggest how difficult it is to reduce greenhouse gas emissions, much less take more controversial steps toward climate engineering. While the House passed a climate bill last year with a complex cap-and-trade system for limiting the nation’s greenhouse gas emissions, the prospects for a Senate bill are much less certain.

Senators John Kerry (D-Massachusetts), Joseph Lieberman (I-Connecticut) and Lindsay Graham (R-South Carolina) have been trying to salvage a bill, but Juliet Eilperin, a national environmental writer for The Washington Post, told the AAAS forum that the prospects for congressional passage of a climate bill this year still looks like “an outsidebank shot”

Learn more about the AAAS Center for Science, Technology, and Sustainability.