Turning atmospheric CO2 into rock in just two years

In a breakthrough towards mitigating climate change, scientists have discovered a quick and permanent method to remove human-produced carbon dioxide from the atmosphere — by turning it into harmless rock.

A new study has shown for the first time that the greenhouse gas carbon dioxide (CO ₂ ) can be permanently and rapidly locked away from the atmosphere, by injecting it into volcanic bedrock.

The CO

₂ reacts with the surrounding rock, forming environmentally benign minerals, researchers said.

Measures to tackle the problem of increasing greenhouse gas emissions and climate change are numerous. One approach is Carbon Capture and Storage (CCS), where CO

₂ is physically removed from the atmosphere and trapped underground. Geoengineers have long explored the possibility of sealing CO ₂ 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 CO _2.

Until now it was thought that this process would take several hundreds to thousands of years and is therefore not a practical option. The new 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.

“Our results show 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,” said lead author Dr Juerg Matter, from University of Southampton in the UK. The study was published in the journal Science.