The BBC reports that Broecker, addressing a literary festival in the U.K., said that roughly 20 million scrubbers would be needed to suck up all the carbon dioxide produced in the U.S. A grand total of 60 million would be needed worldwide to trap all carbon emissions; he estimated that the entire scheme would cost $600 billion a year -- though how he came up with that figure is unclear. Each scrubber would be 50 ft high and 8 ft in diameter and use a special plastic to capture CO2. The gas could be either pumped underground or liquefied under pressure.Echoing many scientists who support geo-engineering, Broecker said current climate mitigation efforts are "just sort of crawling along at a slow pace." Sixty million may seem like a lot, he acknowledged, but, pointing out that the world produces 55 million cars a year, he says building that number over the next 3-4 decades should be feasible. One could argue that it took many decades -- more than 3-4 -- for automakers to optimize their assembly lines and reach such high figures (and that's with the whole world involved), so it remains to be seen if his ideal scenario pans out.
The best place to put these huge tree-like scrubbers would be in the world's desert regions. The toughest obstacle to getting the plan implemented will be political interference, Broecker said. Bringing China, India and other developing countries onboard will be key to ensuring the scheme's longterm success.
Via ::BBC News: Giant trees 'to clear excess CO2' (news website)