Researchers at Columbia University released a report yesterday detailing their discovery that human-generated emissions are causing the world’s oceans to acidify faster than they have in the past 300 million years (a period that includes four extinction cycles). The oceans naturally act as a carbon sponge – the water soaks up CO2, turns it into carbonic acid, and then fossils carbonate shells on the ocean floor to neutralize it. However, the researchers found that recently, because of rising levels of carbon dioxide in the atmosphere, the oceans have been absorbing carbon too quickly and the fossils on the ocean floor have not been able to neutralize it. The over abundance of carbon in the oceans has led to a drastic acidification process that is depriving ocean organisms of carbonate ions that they need to survive.
As if we really needed another terrible side effect to our dependence on burning fossil fuels, it seems we’ve got even bigger fish to fry – perhaps literally if the oceans keep acidifying at this rate. After reviewing hundreds of pale-oceanographic studies the research team, led by the folks at Columbia University’s Lamont-Doherty Earth Observatory, found just one other time period in the last 300 million years that remotely resembled the kind of acidification that we are seeing today. In the past 100 years atmospheric CO2 has risen about 30 percent and the ocean pH level has risen by 0.1 unit, to 8.1. That rise occured at a rate 10 times faster than the last drastic ocean acidification period that occurred 56 million years ago.
During that period 56 million years ago, Paleocene-Eocene Thermal Maximum, or PETM, the oceans slowly became more acidic which killed off small organisms in the ocean. Researchers believe that the result must have been a starving of the food chain from the bottom up that could have caused larger organisms to disappear as well. During that time period the global temperatures also rose by 6 degrees Celsius. The most important note in this study, next to the fact that the phenomenon has now been catalogued, is that we are now seeing a rate of acidification that is occurring at a pace never before seen on Earth. The Intergovernmental Panel on Climate Change believes that the oceans could continue to acidify by as much as 0.3 units by the end of the century which could likely cause a mass extinction similar to that during the PETM period.
“These studies give you a sense of the timing involved in past ocean acidification events—they did not happen quickly,” said Richard Feely, an oceanographer at the National Oceanic and Atmospheric Administration, who worked on the ocean acidification study with the team at Columbia Univeristy. “The decisions we make over the next few decades could have significant implications on a geologic timescale.” Christopher Langdon, an oceanographer at the University of Miami was even more direct in his warning, “once a species goes extinct it’s gone forever. We’re playing a very dangerous game.”
Via SF Gate