Just a few years ago, Iceland’s largest producer of geothermal energy injected 250 tons of carbon dioxide into an underground repository of volcanic rocks. To their surprise, the carbon they had injected underwent a quick chemical reaction and formed into a rock called carbonate in two years’ time. That’s a big deal because it means the gas would not escape back to the atmosphere, leading researchers in America to test whether the results could be reproduced. The results showed they could, suggesting that this procedure for storing carbon could be a key part of the solution to climate change.