At NASA’s Jet Propulsion Laboratory there is a news article posted yesterday that discusses “the other carbon dioxide problem.” That problem is, of course, ocean acidification.
Ocean acidification is the result of CO2 released into the atmosphere finding its way into ocean waters. Estimates are that around one third of all human emissions of CO2 are currently absorbed this way. While that is good news for the problem of an enhanced greenhouse effect causing global warming, it is not good news for marine ecosystems.
In fact it is extremely bad news, and make ocean acidifications one of the most neglected aspects of the whole climate change policy debate. According to the article:
Since the beginning of the industrial era, the pH of surface waters has decreased slightly but significantly from 8.2 to 8.1, and it continues to decrease. Scientists project the pH of surface water will decrease by the year 2100 to a level not seen on Earth over the past 20 million years, if not longer.
20 million years! At least. And like the change in atmospheric chemistry, the calamitous part of that change is its rapidity. Some tens of millions of years ago it was higher than we are headed for, but it did not get there in one century. Marine life will not have the chance to adapt quickly enough. And let’s not forget that marine life is already dealing with our pollution and overfishing.
55 milion years ago there was a huge spike in ocean acidity leading to the extinction of 30-40% of marine species and a major turnover in mamalian species. This is known as the Paleocene-eocene thermal maximun event. Google it, it is likely an excellent preview of what we are doing to the biosphere today.
Also from the article:
Since most corals live in shallow waters, coral reefs, some of the most biologically diverse places on Earth, are particularly vulnerable. “They are already under assault from warming water, over-fishing and habitat degradation,” says Doney. “Environmental stress is leading to more incidents of ‘coral bleaching,’ which occurs when the symbiotic algae that lives inside the coral leaves or dies, and from which reefs often do not recover. Ocean acidification may push corals over the edge.”
So it is a danger for corals as well, which already suffer from warming water.
All in all it is really a bleak picture and is why adaptation should not be on the table as a plan to deal with the emissions problem, though at this point it is a necesity to deal with the changes already well under way. It is also why geoengineering schemes, such as pumping aerosols into the stratosphere or sending sun shades into orbit to reduce insolation, are not going to solve the underlying problem of biodiversity loss. Any proposal that leaves the carbon in the atmosphere is not going to help us out of this mess.
Anyway, that’s my two cents, but the source article is what you should read and pass on.
[update: 90% extinction of marine life in the original version was incorrect, that rate only applied to foraminifera. The text has been ammended.]