An international team of scientists have found a potentially viable way to remove anthropogenic (caused or influenced by humans) carbon dioxide emissions from the atmosphere - turn it into rock.

The study, published in Science, has shown for the first time that the greenhouse gas carbon dioxide (CO₂) can be permanently and rapidly locked away from the atmosphere, by injecting it into volcanic bedrock. The CO₂reacts with the surrounding rock, forming environmentally benign minerals.

Measures to tackle the problem of increasing greenhouse gas emissions and resultant climate change are numerous. One approach is Carbon Capture and Storage (CCS), where CO₂ is physically removed from the atmosphere and trapped underground. Geoengineers have long explored the possibility of sealing CO₂ gas in voids underground, such as in abandoned oil and gas reservoirs, but these are susceptible to leakage. So attention has now turned to the mineralisation of carbon to permanently dispose of CO₂.

Until now it was thought that this process would take several hundreds to thousands of years and is therefore not a practical option. But the current study -- led by Columbia University, University of Iceland, University of Toulouse and Reykjavik Energy - has demonstrated that it can take as little as two years. Study shows that between 95 and 98 per cent of the injected CO₂ was mineralised over the period of less than two years, which is amazingly fast.

The gas was injected into a deep well at the study site in Iceland. As a volcanic island, Iceland is made up of 90 per cent basalt, a rock rich in elements such as calcium, magnesium and iron that are required for carbon mineralisation. The CO₂ is dissolved in water and carried down the well. On contact with the target storage rocks, at 400-800 metres under the ground, the solution quickly reacts with the surrounding basaltic rock, forming carbonate minerals.