Global warming is causing a silent storm in the oceans by acidifying waters at a record rate, threatening marine life from coral reefs to fish stocks, an international study showed on Thursday.
The report, by 540 experts in 37 nations, said the seas could become 170 percent more acidic by 2100 compared to levels before the Industrial Revolution. Carbon dioxide, the main greenhouse gas, can become a mild acid when mixed with water.
Acidification is combining with a warming of ocean waters, also caused by a build-up of greenhouse gases in the atmosphere, and other man-made factors such as higher pollution and overfishing, the report said.
The study, released on the sidelines of a meeting of almost 200 nations in Warsaw on ways to slow global warming, estimated that acidity of the oceans had already increased by 26 percent since the Industrial Revolution in the 18th and 19th centuries.
A 170 percent increase in acidity is equivalent to cutting the Ph level of the ocean, a scale of acidity and alkalinity, to 7.9 from 8.2 on a logarithmic scale. Battery acid rates about 1 and soap, an alkaline, is about 10.
The pace of acidification was the fastest in at least 55 million years, the scientists said. Acidification undermines the ability of everything from corals to crabs to build protective shells and has knock-on effects on the food web.
Deep cuts in emissions of greenhouse gases, from power plants, factories and cars, would limit acidification.
The Warsaw talks are working on plans for a global deal, due to be agreed in 2015, to limit climate change.