AP Photo/Greg Baker
A group of US scientists has made a breakthrough in developing "carbon scrubbers" to remove excess CO2 from the atmosphere.
Led by Columbia University physicist Klaus Lackner and backed by a private company in Tuscon, Ariz., called Global Research Technologies, the team is working to build a giant "tree" that draws in air and passes it over an ion exchange membrane that traps the carbon dioxide. The gas could then be deposited underground, pumped into a greenhouse where it would help plants grow, or put to some other use.
The scientists say the device could remove about one ton of CO2 per day from the atmosphere. The average American produces about 20 tons of carbon dioxide each year, contributing to a total worldwide output of about 27 billion tons annually.
Scientists have speculated about such devices for a few years now (the BBC documented Lackner's efforts in early 2003), but were unable to find an inexpensive way of separating the trapped carbon from the absorber membrane. But the Guardian, which obtained one of Lackner's team's patent applications, reports that the scientists have recently discovered that passing humid air over the membranes causes them to "exhale" carbon dioxide. This development, say scientists, reduce the scrubber's energy use "tenfold."
The June issue of Smithsonian Magazine features a Q&A with Wallace Broecker, one of the lead scientists on this project. Broecker, the Columbia university climate expert who was the first to coin the term "global warming" in the 1970s, describes a device "about 6 to 10 feet in diameter, 50 feet high ... like a little silo, in that shape so the wind could blow through it from any direction."