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For anyone uneasy about messing with the chemistry of the ocean--which is probably pretty much everyone--there is one more way to go, and it's being studied in a warehouse in Tucson, Ariz., by a company named Global Research Technologies (GRT). Developed by GRT president Allen Wright and Columbia University physicist Klaus Lackner, the system consists of 32 hanging plastic panels, each 9 ft. high and 4 ft. deep (2.7 by 1.2 m), spaced about half an inch apart. As air wafts through those spaces, CO2 sticks to the proprietary plastic the panels are made of. The device in Tucson is now scrubbing about 50 lb. (23 kg) of CO2 a day out of the air. "If we built one the size of the Great Wall of China," Wright says, "and it removed 100% of the CO2 that went through it, it would capture half of all the emissions in the world."
What Wright actually envisions is not a Great Wall of proprietary plastic, but fields of much smaller, mass-produced scrubbers, each fitting into a 40-ft.-long (12 m) shipping container. Scatter 20 million of them in remote spots around the world, and you could take care of the emissions from all the vehicles on the planet. And what do you do with the carbon you collect? For starters, you could sell captured greenhouse gasses to, well, greenhouses; farmers pay up to $300 per ton for the stuff to help plants grow. If the scrubbers were deployed on a grand scale, though, lakes of liquid CO2 would need to be pumped into deep underground reservoirs. A more exciting--if more remote--possibility is to combine CO2 with hydrogen and convert it back into fuel that cars could burn again. This would release more CO2, which scrubbers would pull back out of the air, in a closed loop.
Right now, most of the considerable skepticism directed at the idea concerns price and scale. But there's skepticism toward any technology that aims to reinvent the way we produce energy and clean up the mess it makes, whether it's air scrubbers, ocean-seeding, windmills or nuclear plants. The only point of nearly universal agreement is that we can't keep going the way we are now. A little imaginative science just may produce some of the many answers we so badly need.
To watch more of Anderson Cooper's worldwide investigation Planet in Peril, tune in to AC360° on CNN, Mondays at 10 p.m. E.T. and visit CNN.com/planetinperil Also, don't miss the new documentary Planet in Peril: Battle Lines, coming this fall