Many scientists cite 350 parts per million of Carbon dioxide in the atmosphere as the magic number where we escape the effects of global warming. We’re currently at over 380 parts per million and that number is going up all the time. So how can we get back below the tipping point? One Columbia University scientist thinks he has a solution: gigantic fake trees that absorb CO2 right out of the air!


[Creative Commons photo by Bill Ward]

Klaus Lackner, Director of the Lenfest Center for Sustainable Energy at Columbia University’s Earth Institute, got his idea for the design from his daughter’s eighth grade science project. Six years later, he’s working on a full-sized model that has the potential to remove tons of CO2 from the air. So how does this work?

The secret is lye. The giant “tree,” which looks sort of like an enormous fly swatter, sucks in air. The lye then bonds with the CO2, trapping it. It removes between two-thirds and three-quarters of the CO2 in the air that filters through it. That means that if the air coming in is at 385ppm, it leaves the device at between 257ppm and 266ppm – well below the 350 tipping point.

Fake Plastic Forest
The full scale version of Lackner’s tree would be about the size of a football field goal post. In an interview with Paul Solman on PBS’s NewsHour, Lackner said, “Such a device could collect the CO-2 from 4,000 people or, alternatively, the CO-2 from 15,000 cars.” He says it would take about 250,000 across the world to filter out our excess CO2 and get us back to neutral. In a few decades, twice that number could reduce the CO2 in the air to the level before the Industrial Revolution. That’s a lot of trees!

Since CO2 spreads through the air once it’s emitted, the trees wouldn’t necessarily need to be “planted” right next to the main offenders, like coal fired power plants, highways, or airports. They would work anywhere. Lackner is hopeful that this technology will become more and more affordable:

With off-the-shelf items we have right now, I can drive the cost of CO-2 capture from air below $100 per ton of CO-2. And I feel that, if you pursue this longer, the ultimate end game will be below $30 per ton of CO-2.

My Take
How amazing! It seems almost too good to be true. My only concern with technology like this is that quick fixes sometimes ignore the complexity of the issue. Yes, CO2 emissions from coal fired power plants are a huge part of the problem. Carbon capture isn’t the panacea, though. Oil and gas technology pollutes beyond just what’s spewed into the air. We can’t forget events like the disaster in Tennessee and the one at the coal plant in Alabama. Inventions like Lackner’s could definitely be part of the solution, but they aren’t the whole solution.