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Tuesday, April 23, 2013

Sequestration That Makes Sense

We all know that sequestration on the government level is a cop-out. It's like using a baseball bat to swat a fly. But, a different kind of sequestration — sucking carbon right out of the air — may be a way to reverse Global Warming according to A way to curb global warming: Suck carbon emissions right out of the air?:

Efforts to combat global warming, triggered and reinforced by rising levels of carbon dioxide as humans burn fossil fuels and convert forests to farmland, largely focus on preventing CO₂ from entering the atmosphere in the first place.

But small groups of researchers are pursuing a complementary approach. They are looking for ways to remove CO₂ already in the air.

On small scales, the approach has been used since the 1930s at dry-ice facilities, as well as to scrub CO₂ from the air on submarines and on the International Space Station. Proposals to use air capture to help reduce atmospheric CO₂ concentrations first appeared in 1999.

However, "over the last two or three years, there's been a lot of new [research] publication in this field," says Alain Goeppert, a researcher with the Loker Hydrocarbon Research Institute at the University of Southern California (USC).

The interest is driven in no small part by a handful of start-up firms that are developing prototype air-capture systems. But it's also driven by the recognition that CO₂ concentrations in the atmosphere already exceed a level that some scientists say stands the best chance of holding global warming by the end of this century to about 2 degrees Celsius (3.6 degrees Fahrenheit) above preindustrial levels.

Air capture essentially involves passing ambient air across liquid or solid materials that absorb CO₂. Conceptually, it's similar to extracting CO₂ from coal-fired power-plant emissions.

But air-capture advocates note that some 30 percent of the world's CO₂ emissions come from cars, aircraft, and other mobile "nonpoint" sources, where scrubbers at the tailpipe are impractical.

Tackling emissions from these sources will be necessary in order to meet any goal for stabilizing CO₂ levels in the atmosphere, because the CO₂ that oceans or terrestrial vegetation don't take up remains in the air for centuries. Stabilizing concentrations essentially means stopping the emission of additional CO₂.

"Without air capture, nonpoint sources of emission will need to be phased out over the next few decades if we want to stabilize the climate," argues Klaus Lackner, director of Columbia University's Lenfest Center for Sustainable Energy and a founder and director of Kilimanjaro Energy, one of the start-ups working on air-capture technologies, in an article published last year in the Proceedings of the National Academy of Sciences.