Report: Oceans more acidic
The escalating level of carbon dioxide in the atmosphere is making the world’s oceans more acidic, government and independent scientists say. They warn that, by the end of the century, the trend could decimate coral reefs and creatures that underpin the sea’s food web.
Although scientists and some politicians have just begun to focus on the question of ocean acidification, they describe it as one of the most pressing environmental threats facing the Earth.
“It’s just been an absolute time bomb that’s gone off both in the scientific community and, ultimately, in our public policymaking,” said Rep. Jay Inslee, D-Wash., who received a two-hour briefing on the subject in May with five other House members. “It’s another example of when you put gigatons of carbon dioxide into the atmosphere, you have these results none of us would have predicted.”
A coalition of federal and university scientists will issue a report today describing how carbon dioxide emissions are, in the words of a press release from the National Center for Atmospheric Research and the National Oceanic and Atmospheric Administration, “dramatically altering ocean chemistry and threatening corals and other marine organisms that secrete skeletal structures.”
For decades, scientists have viewed the ocean’s absorption of carbon dioxide as an environmental plus, because it mitigates the effects of global warming. But by taking up one-third of the atmosphere’s carbon dioxide – much of which stems from exhaust from automobiles, power plants and other industrial sources – the ocean is transforming its pH level.
The pH level, measured in “units,” is a calculation of the balance of a liquid’s acidity and its alkalinity. The lower a liquid’s pH number, the higher its acidity; the higher the number, the more alkaline it is. The pH level for the world’s oceans was stable between 1000 and 1800 but has dropped one-tenth of a unit since the Industrial Revolution, according to Christopher Langdon, a University of Miami marine biology professor.
Scientists expect ocean pH levels to drop by another 0.3 units by 2100, which could seriously damage marine creatures that need calcium carbonate to build their shells and skeletons. Once absorbed in seawater, carbon dioxide forms carbonic acid and lowers the ocean’s pH, making it harder for corals, plankton and tiny marine snails called pteropods to form their body parts.