In a breakthrough towards mitigating climate change, an international team of researchers has discovered a quick and permanent method to remove greenhouse gas carbon dioxide (CO2) from the atmosphere by turning it into harmless rock. This study could overcome the leakage problems that have plagued attempts to bury CO2 gas underground.

Since a long time, Geoengineers have been exploring the possibility of sealing CO2 gas in voids underground, such as in abandoned oil and gas reservoirs, but these are susceptible to leakage. So their attention has now moved to the mineralization 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 new study led by University of Iceland, Columbia University, 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 % 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 the University of Southampton in England.

The gas was injected into a deep well at the study site in Iceland. As a volcanic island, Iceland is made up of 90 % basalt, a rock rich in calcium, magnesium, and iron that are required for carbon mineralization. When the scientists pumped CO2 emissions back into the earth, the carbon dioxide reacted with other chemicals in the basalt rocks and changed chemically to a solid. The acidic mixture dissolved the rocks’ calcium magnesium and formed limestone, a permanent natural jail for the heat-trapping gas, according to Juerg Matter.

“Carbonate minerals do not leak out of the ground, thus our newly developed method results in permanent and environmentally friendly storage of CO2 emissions,” said Matter. “On the other hand, basalt is one of the most common rock types on Earth, potentially providing one of the largest CO2 storage capacity.”

“Storing CO2 as carbonate minerals significantly enhances storage security which should improve public acceptance of Carbon Capture and Storage as a climate change mitigation technology,” Matter added.

The study was published in the journal Science.