By squirreling away carbon dioxide beneath the Earth’s surface, we might be able to reduce the amount that accumulates in the atmosphere. Now, a team of scientists hope that close consideration of samples taken from a rare outcrop of Earth’s mantle could help us store the gas underground more efficiently.
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Burning fossil fuels creates carbon dioxide that usually floats up into the air, but it is possible to capture it and pump it deep into the Earth. Often that’s achieved by forcing it into old oil and gas reservoirs at high temperature and pressure, but that approach can see it escape.
More recently, a project in Iceland has shown that simply pumping the gas underground in the right parts of world can see it react with calcium, magnesium, and iron to form carbonate minerals like limestone. It’s thought that this petrification could lock up the CO2 for hundreds or thousands of years, and more recently it was shown that the process works more swiftly than expected—good news if we want to try and mitigate some of the effects of or continued fossil fuel use sooner rather than later.
But some researchers think the process could be made more efficient. In the mountains of Oman, scientists are studying the only exposed section of Earth's mantle, where the reactions that are being exploited in Iceland occur naturally at the planet’s surface. The Associated Press reports that researchers led by Peter Kelemen from Columbia University have spent four months drilling for samples, and now plan to analyze 13 tons of rock in order gain a more nuanced understanding of how the petrification occurs.
The hope is that by better understanding the process, the team will be able to replicate nature’s own carbon sequestration system. The team hopes to work out how the outcrops in Oman soak up CO2, and Kelemen has grand visions of using the insights to create huge submarine carbon sinks. In the meantime, though, turning CO2 into rock remains little more than a research project—even in Iceland, where currently just 5,000 tons of the gas are pumped underground per year.
Instead, America will continue to look to more conventional carbon-capture techniques. While the Kemper carbon sequestration project in Mississippi may have been an unmitigated disaster, things could be starting to look up for the technology. The Petra Nova coal power plant in Texas recently reopened successfully, using its captured CO2 to help a nearby well pump oil out of the ground more effectively. And, as Vox pointed out this week, a new bipartisan movement could help encourage the wider adoption of similar schemes in the future.
(Read more: Associated Press, Vox, “A Power Plant in Iceland Deals with Carbon Dioxide by Turning It into Rock,” “A Mississippi Power Plant Highlights All That’s Wrong with 'Clean Coal,'” “Researchers say Earthquakes Would Let Stored CO2 Escape”)