The government is committed to reducing atmospheric carbon dioxide to slow climate change and carbon capture and storage is one potential solution. It was not known how the gas could be securely trapped underground until a team of international researchers, led by the University of Manchester, used two specialised techniques to investigate. They measured the ratios of the stable isotopes of carbon dioxide and noble gases in various gas fields and found that underground water is the major carbon dioxide sink in these gas fields and has been for millions of years.

Investigating natural gas fields has provided an insight to how they could be used in the future for carbon capture and storage. Dr Stuart Gilfillan, the lead researcher from the University of Edinburgh, said: “We’ve turned the old technique of using computer models on its head and looked at natural carbon dioxide gas fields which have trapped carbon dioxide for a very long time. By combining two techniques, we’ve been able to identify exactly where the carbon dioxide is being stored for the first time. We already know that oil and gas have been stored safely in oil and gas fields over millions of years. Our study clearly shows that the carbon dioxide has been stored naturally and safely in underground water in these fields.”

The project director, Professor Chris Ballentine from the University of Manchester said: “This new approach will also be essential for monitoring and tracing where carbon dioxide captured from coal-fired power stations goes when we inject it underground. This is critical for future safety verification.”

By Leila Sattary