'Eating Carbon': Article Summary

The article ‘Eating Carbon’ was printed in The Economist on the 13th of November 2008. The link to the article is: http://www.economist.com/research/articlesbysubject/displaystory.cfm?subjectid=348924&story_id=12592256

Past methods of carbon dioxide emission reduction include pumping the gas into underground caverns or into old oil fields. However, peridotite, a rock found in the upper mantle of the earth, has a huge appetite for the gas that can be increased with human interference; it therefore presents an alternate method. Though the rock’s original location, 20 km from the surface, would pose a difficulty in reaching it, plate tectonics have forced parts of the mantle, and therefore peridotite, to the surface. This has occurred in, for example, the Omani desert and along the coasts of Greece and Croatia. Peridotite, when exposed to air, reacts quickly with carbon dioxide to form carbonates such as limestone; this has been known to geologists for some time.The application of the use of peridotite has experienced some difficulties. For example, it has been suggested that ground up peridotite could be used to soak up power stations emissions; however, transport would be very costly and create more emissions. An alternative was presented by Peter Kelemen and Juerg Matter, from Columbia University, stating that channeling the emissions from their production site to underground layers of peridotite would be more efficient. Peridotite absorption rates could further be increased by drilling and fracturing the rock. Alone the Omani deserts outcrop could absorb 4 billion tons of carbon dioxide a year, a large fraction of the 30 billion tons that humans produce in a year. Therefore, peridotite has the potential to significantly decrease the carbon dioxide levels in certain regions, though it is limited by the fact that it is only located in a few select locations.