Researchers raise climate change hopes by turning carbon dioxide into stone

Scientists have turned carbon dioxide into stone in a matter of months by pumping it deep underground, offering a revolutionary new way of storing the greenhouse gas to tackle climate change. The pioneering experiment in Iceland mixed CO2 emissions with water and pumped it hundreds of meters underground into volcanic basalt rock – where it rapidly turned into a solid. “We need to deal with rising carbon emissions. This is the ultimate permanent storage – turn them back to stone,” said researcher Juerg Matter.

It was a huge surprise to all the scientists involved in the project, and we thought, ‘Wow! This is really fast’

Researcher Juerg Matter, from the University of Southampton

The promising results come from the Carbfix project at Iceland’s Hellisheidi plant – the world’s largest geothermal facility, which powers Reykjavik and produces 40,000 tons of CO2 a year. In 2012, researchers began pumping 250 tons of CO2 mixed with water underground. They feared it could take hundreds or even thousands of years for the mildly acidic liquid to solidify. But 95% of the injected mixture had became chalky white stone within two years. “In the future, we could think of using this for power plants in places where there’s a lot of basalt – and there are many such places,” said researcher Martin Stute,