Researchers Discuss Understudied Geoengineering Approaches to Climate Change

Reducing greenhouse gas emissions or adapting to their consequences are the best-known strategies for dealing with climate change, but geoengineering strategies deserve closer attention, experts said at a Capitol Hill briefing.

Geoengineering refers to large-scale engineering of the environment, and speakers at the briefing said that greater focus on understudied geoengineering approaches could provide a better understanding of the range of options available for dealing with climate change. The event, organized by the American Meteorological Society and held on 12 April, was co-sponsored by AAAS.

“We can think about large-scale manipulation of the Earth’s system, geoengineering, in the hopes of counteracting at least some of the consequences of climate change,” said Paul Higgins, associate director for the American Meteorological Society Policy Program.

Ken Caldeira, a climate scientist at the Carnegie Institution Department of Global Ecology explained different methods of removing carbon dioxide from the atmosphere. He stressed that it is important to keep in mind the cost and scalability factors when discussing possible approaches. A centralized approach would include an industrial carbon capturing facility, he said, while distributive approaches that pull carbon dioxide out of the atmosphere into biological or chemical sinks would require large amounts of space.

David Keith from the University of Calgary's department of chemical and petroleum engineering focused on a different type of geoengineering: the Solar Radiation Management (SMR) approach, which involves reflecting sunlight to space.

SMR may be a relatively fast and cheap fix, Keith said, but he also called the approach “imperfect and uncertain.”

“We have a situation where there’s still no organized research program in the U.S. anyway, and yet there’s increasing attention paid to this, for better or for worse,” Keith said.

While speakers presented different approaches to climate engineering, Keith stressed there is no need to group all forms of geoengineering together into one program.

“Solar Radiation Management has, I think, no useful connections to carbon dioxide removal,” Keith said. “They’re not more connected to each other than either of them are to abatement, reducing emissions, or to adaptation.”

Carla Schaffer

5 May 2011