Manmade emissions over the last two centuries have already raised ocean acidity far beyond the range of natural variations, threatening important species of marine life.
“In some regions, the man-made rate of change in ocean acidity since the Industrial Revolution is 100 times greater than the natural rate of change between the Last Glacial Maximum (21,000 years ago) and pre-industrial times,” said Tobias Friedrich, from the University of Hawaii.
Friedrich and Axel Timmermann, also from Hawaii University, led a team of marine chemists, conservationists, biologists and ecologists, to simulate climate and ocean conditions from 21,000 years ago, to the current day, with the help of computer modelling, the journal Nature Climate Change reports.
The research team analysed changes in the saturation level of aragonite (a form of calcium carbonate) used to measure ocean acidification. As acidity rises, saturation level of aragonite drops, according to a Hawaii statement.
Current levels of aragonite saturation have already dropped five times below the pre-industrial range. Thanks to fossil fuels, saturation levels will drop further, reducing calcification rates of some marine organisms by more than 40 percent of their pre-industrial values.
“When earth started to warm 17,000 years ago, terminating the last glacial period, atmospheric CO2 levels rose from 190 parts per million (ppm) to 280 ppm over 6,000 years,” says Friedrich.
“Marine ecosystems had ample time to adjust. Now, for a similar rise in CO2 concentration to the present level of 392 ppm, the adjustment time is reduced to only 100 – 200 years,” adds Friedrich.
Nearly a third of manmade carbon dioxide (CO2) emissions finds its way into the sea, every year, reacting with the water to increase its acidity, threatening corals and other species.
-Indo-Asian News Service