Researchers report on a safe storage method for man-made carbon dioxide beneath deep-sea sediments:

Deep-sea sediments could provide a virtually unlimited and permanent reservoir for carbon dioxide, the gas that has been a primary driver of global climate change in recent decades, according to a team of scientists that includes a professor from MIT.

The researchers estimate that seafloor sediments within U.S. territory are vast enough to store the nation’s carbon dioxide (CO2) emissions for thousands of years to come.

“The exciting thing about this paper is that we show that CO2 injected beneath the seafloor is sequestered permanently,” said Charles Harvey, an associate professor in MIT’s Department of Civil and Environmental Engineering. Harvey is a co-author of a paper on the work that appears in this week’s issue of the Proceedings of the National Academy of Sciences.

“CO2 injected underground on land is buoyant, and hence has the potential to escape back to the surface,” Harvey said. “This is not the case under the deep ocean. Because the ocean floor is so cold, liquid CO2 stored beneath the floor is denser than water and will not rise to surface. Furthermore, the top of the injected CO2 plume will form a hydrate, an ice-like solid that plugs up the pore spaces, ’self-sealing’ the injected CO2 plume into the deep sea sediments.”