By Sid Perkins
Almost half the carbon dioxide produced by human activity in the past 2 centuries is now dissolved in the oceans. It’s wreaking chemical changes there that, if unchecked, could threaten the capacity of corals and other marine organisms to make their hard shells and skeletons, scientists say.
From 1800 to 1994, fossil fuel use and industrial processes such as cement production generated some 900 billion metric tons of carbon dioxide. Atmospheric concentrations of the planet-warming greenhouse gas rose during that period from about 280 parts per million to around 360 ppm, says Christopher L. Sabine, an oceanographer at the National Oceanic and Atmospheric Administration (NOAA) in Seattle. He reports that data garnered during more than 95 recent transoceanic research cruises suggest that much carbon dioxide ended up in the oceans as well.