At a power plant in Iceland, volcanic rock is being used to transform carbon dioxide into salt-like crystals. Underground, the greenhouse gas becomes solid in a matter of months, mimicking a natural process that can take centuries.

The research, detailed Thursday in the journal Science, is part of a larger quest to capture carbon at power plants and then store it underground. Solidifying the carbon could reduce the risk of it leaking out into the atmosphere, contributing to climate change.

At the Hellisheidi geothermal plant near Reykjavik, researchers dissolve carbon dioxide in water and inject it into basalt rock, which chemically reacts with the gas, mineralizing it. The project, dubbed Carbfix, began in 2007.

“The conventional wisdom has been