Could we geoengineer the climate with CO2?
Schemes for artificially cooling the planet can often seem wild and woolly. The latest such geoengineering scheme is no different: it involves frozen carbon dioxide, Antarctica and a whole lot of freezers. While the proposal is not as daft as it sounds, the numbers may not stack up.
Ernest Agee and colleagues of Purdue University in West Lafayette, Indiana, propose installing gigantic freezers in the heart of Antarctica, where temperatures are already tens of degrees below zero. Once the air inside the freezers is cooled to -140 °C, the carbon dioxide within it will freeze out as “CO2 snow”. The solid CO2 could then be stored underground.
Agee’s calculations suggest that it would be possible to remove 1 billion tonnes of CO2 per year this way, using the energy provided by 16 wind farms, each generating 1200 megawatts of electricity. “There’s a lot of wind energy in the Antarctic,” Agee says.
Our annual greenhouse gas emissions reached 33 billion tonnes of CO2 in 2010, and are likely to keep rising for years to come, so Agee’s proposal would only go so far. The sheer scale of our emissions is a problem for similar concepts for sucking CO2 out of the air, such as fertilising the ocean with iron.