Stanford scientists link ocean acidification to prehistoric mass extinction

In a new study released by Stanford University in April 2010, scientists have found evidence that links ocean acidification due to volcanic eruptions 250 million years ago, with the wiping out of 90% of marine species and 75% of land species. This event called the “end-Permian” extinction has conditions parallel to the combination of ocean acidification that is happening currently and the increasing concentrations of CO2 in the atmosphere.

Read the full Stanford University article here, which also quotes the National Research Council as reporting that:

the ocean’s chemistry is changing faster than it has in hundreds of thousands of years, because carbon dioxide is being released into the atmosphere and absorbed into the oceans, making them more acidic. Studies have shown increased ocean acidity decreases photosynthesis, nutrient absorption, growth and reproduction of marine organisms.

 
It’s also of increasing concern that due to the soaring acidity in oceans, they are no longer able to absorb human induced carbon emissions as fast as before, according to the report in Nature  in November 2009. The current rate of ocean acidification is up to 10 times faster than 55 million years ago  which was the last time the deep oceans became so acidic.

According to a Time magazine article:

A new study by the University of East Anglia and the British Antarctic Survey estimated that emissions have jumped 29% since 2000. The Nature study found that over the same period, the proportion of fossil-fuel emissions absorbed by the oceans has fallen by as much as 10%. Though it’s not clear why, the fact seems to be that the oceans’ absorption ability can’t keep up with the rate at which we’re burning fossil fuels. That’s troubling because even under the most optimistic projections, man-made carbon emissions aren’t likely to decline for years. “There’s a physical limit to how rapidly the oceans can absorb CO2,” says Khatiwala. “The ocean becomes a less efficient sink.”

 

Last year NRDC (National Resource Defence Council) released a video called Acid Test, narrated by Sigourney Weaver. It talks about the importance of our oceans and the consequences of increasing acidification of oceans.

 

This reduced ability of oceans to absorb CO2 emissions has an important bearing on the decisions of nations to reduce carbon emissions. The underlying assumption behind the IPCC studies, as well as the COP15 Climate Summit at Copenhagen in December 2009, was that oceans and forests, the natural sinks of the world have the ability to absorb about 50% of man-made carbon emissions.  As forests disappear and oceans become more acidic, they absorb less carbon, and increase the rate of global temperature rises.   Predictions about future temperature rises and related policy decisions have to factor in the reduced efficiency of oceans as carbon sinks.

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