Read the full story in Quartz.
Trees can suck carbon dioxide from the air. But we continue to put so much of it in the atmosphere that we have to deploy other technologies too, such as “direct air capture” (DAC). It involves using a fan to pass air over a surface containing a chemical agent that only reacts with carbon dioxide, then exposing the newly formed compound to heat. That energy breaks the bond, reversing the reaction and releasing carbon dioxide, which can be stored or put to some use.
Climeworks has built and operated DAC plants for more than a year. In May 2017, it launched its first one, capable of capturing 900 metric tons annually, in Zurich, Switzerland. The carbon dioxide captured was fed to a greenhouse, which boosted the growth of the plants inside it. Last year, the company began operating the second, capturing 50 metric tons each year, near a geothermal power plant in Hellisheidi, Iceland. The captured gas is injected underground along with water, where it reacts with basalt rocks and turns into rock in less than two years.