The Oman geoengineering scheme to save the planet

A story in the Arizona Daily Star, 4-14-17 (the great march for science issue) shows how some scientists create the most tenuous links between their research and climate change as a plea for funding.

This story is “Oman’s mountains may hold clues for reversing climate change.” (Link) The lede: “Deep in the jagged red mountains of Oman, geologists are searching for an efficient and cheap way to remove carbon dioxide from the air and oceans — and perhaps begin to reverse climate change. They are coring samples from one of the world’s only exposed sections of the Earth’s mantle to uncover how a spontaneous natural process millions of years ago transformed carbon dioxide into limestone and marble.”

The researchers are excited because the exposed mantle rock is mostly peridotite, a coarse-grained igneous rock made up of the minerals olivine and pyroxene, both magnesium silicates. “They hope to answer the question of how the rocks managed to capture so much carbon over the course of 90 million years — and to see if there’s a way to speed up the timetable.” A researcher goes on to say, ““Every single magnesium atom in these rocks has made friends with the carbon dioxide to form solid limestone, magnesium carbonate, plus quartz.”

A couple of nitpicks: Limestone is calcium carbonate, not magnesium carbonate (Calcium and magnesium together with carbonate form a rock called dolomite). Marble is a metamorphic rock which requires heat and/or pressure to form. That “spontaneous natural process” happened not only millions of years ago, but is a continuing natural process in the ocean when calcium ions derived from weathering of surface rocks combine with carbonate ions in the ocean. Basaltic ocean crustal rocks act as a buffer by continuously removing CO2 from the ocean by combining carbonate with calcium derived from surface weathering of rocks.

Their great scheme is this: “a drilling operation could cycle carbon-rich water into the newly formed seabed on oceanic ridges far below the surface. Just like in Oman’s mountains, the submerged rock would chemically absorb carbon from the water. The water could then be cycled back to the surface to absorb more carbon from the atmosphere, in a sort of conveyor belt.”

Perhaps the researchers made the climate change link to their research just to suck up grant money so they can continue studying. The geology is interesting, but their idea sounds like another crazy, expensive, and totally unnecessary geoengineering scheme. (See Wacky Geoengineering Schemes to Control Climate)

See also:

Evidence that CO2 emissions do not intensify the greenhouse effect

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