Physicists at Columbia University in New York say that they have made a breakthrough in developing a device which can “suck” carbon dioxide out the air.

Scientists have been sceptical about the possibility of using “scrubbers” to extract carbon dioxide from the air because, although it is easy to get chemicals to absorb carbon dioxide, it takes a large amount of energy to release the carbon dioxide for use or storage. The Columbia University team, led by Klaus Lackner, says that it can capture the carbon dioxide using ion exchange membranes (commonly used in purifying water) and then make the membranes “exhale” the carbon dioxide using just humid air.

The team plans to demonstrate a prototype, capable of extracting a tonne of carbon dioxide a day from the air, within two years. The prototype would fit in a shipping container and cost about $200,000. It could be connected to a greenhouse so that the captured carbon dioxide could be used to stimulate plant or algae growth for food, fuel or fertilizer.