In a press conference presentation Wednesday, Reykjavik Energy’s Edda Aradóttir described the company’s new project as “turning the CO 2 troll to stone.” If deployed at scale, the technology behind this could make a big difference in charting a better climate future—capturing CO 2 gas and locking it away underground before it can add to the growing greenhouse effect.

Last year, the people behind the project, which is termed “CarbFix,” published a paper outlining the remarkable success they’d had in pilot operation. CO 2 captured from a geothermal power plant (the hot geothermal water comes up with some volcanic CO 2 as well) was injected back down into the Icelandic basalt, where it reacted with the rock and turned into carbonate minerals. This is the ultimate fate for CO 2 injected underground everywhere, but it usually takes hundreds to thousands of years. In the basalt, the CO 2 had mineralized in a matter of years, making this a particularly attractive way to deal with the CO 2 troll.

Meanwhile, a young company in Switzerland called Climeworks was opening its first plant to capture CO 2 —not from relatively concentrated smokestack effluent, but from ambient air. CO 2 is much more dilute in ambient air, comprising about 0.04 percent of atmospheric gas currently. So capturing it economically is much more difficult. For that reason, efforts to develop this particular technology have been slow in coming.

In the case of Climeworks’ first plant, the captured CO 2 is being sold to a nearby greenhouse. But on Wednesday, the company announced it had flipped the switch on a smaller facility connected to the CarbFix project in Iceland. So in addition to the CO 2 captured from Reykjavik Energy’s geothermal power plant, CO 2 sucked in from the atmosphere is now being sent down into the basalt for permanent stone storage—a first.

The volume of CO 2 being captured isn’t very large, so this is more about proving the concept than making a significant dent in the global problem. Climeworks’ design is modular, consisting of blowers that move ambient air through carbon-capturing filters. The amine chemicals in these filters let go of the CO 2 when heated. That heating step is nicely facilitated by hot water from the geothermal plant.

Climeworks’ Swiss plant is an array of 18 blower units, together capable of capturing about 900 tons of CO 2 per year, which is about what 55 average Americans emit. The company has installed one of these units (so capturing only about 50 tons per year) in Iceland as a test. Climeworks has ambitious goals for the future, though. Co-founder Jan Wurzbacher explained that, in 2019, the company hopes to build a larger plant capable of capturing several thousand tons of CO 2 each year at the CarbFix facility in Iceland. And the aspirational 2025 goal is for Climeworks installations to be capturing one percent of global emissions (which would be in the neighborhood of 350 million tons).

Any step in that direction by Climeworks or one of the other companies working on similar technology—even if it’s a small step—moves us a little closer to being able to remove meaningful amounts of climate-changing carbon dioxide from the atmosphere. And that becomes increasingly necessary the longer we take to eliminate greenhouse gas emissions.