The Big Idea
Carbon capture
Art: Splashlight. Source: Klaus Lackner, Lenfest Center for Sustainable Energy, Columbia University
Scrubbing the Skies
Pulling CO2 back out of the air might be easier
than building jets and cars that don’t emit it.

Every time you drive to work, or worse yet, fly on a plane, the vehicle emits carbon dioxide that will stay in the atmosphere, warming the planet for thousands of years. Does it have to? Trees can take CO2 back out again—but even covering the planet with forests wouldn’t solve our problem, and there would be an awful lot of wood to preserve. (If allowed to rot or burn, trees release their carbon again.) Physicist Klaus Lackner thinks he has a better idea: Suck CO2 out of the air with “artificial trees” that operate a thousand times faster than real ones.

They don’t exist yet, and when they do, they probably won’t look like real trees. But in Lackner’s lab at Columbia University he and colleague Allen Wright are experimenting with bits of whitish-beige plastic that you might call artificial leaves. The plastic is a resin of the kind used to pull calcium out of water in a water softener. When Lackner and Wright impregnate that resin with sodium carbonate, it pulls carbon dioxide out of the air. The extra carbon converts the sodium carbonate to bicarbonate, or baking soda.