Cancun Climate Conference
8:40 am
Fri December 10, 2010

Ocean acidification: Global warming's evil twin

The focus of attention at the U.N. climate summit in Cancun, Mexico is global warming caused by too much carbon dioxide in the atmosphere. But there’s another impact of high carbon levels that poses a whole different set of problems: it makes the ocean more acidic.

I spoke today with Ellycia Harrould-Kolieb. She’s a scientist for Oceana,  an international science-based non-profit that works on ocean issues. The group just put out a report here in Cancun showing there’s a growing body of evidence that, as the ocean becomes more acidic, new problems are emerging.

I like to call ocean acidification global warming’s evil twin. The ocean absorbs as much as half the carbon dioxide we put into the atmosphere. The CO2 bonds with water and forms carbonic acid. And that interferes with the ability of sea critter to form their shells.

That’s got all kinds of implications for everything from tiny plankton critters called pteropods to shellfish like oysters and clams. Harrould-Kolieb pointed out to me that’s having impacts all over the world, including in the Salish Sea.

“There have been decreases in the shellfish hatcheries, the ability to raise larval oysters, and we think that’s connected to rising acidity along the Pacific Coast. We’re also seeing decreases in coral growth, on the Great Barrier Reef (in Australia), and we think that’s also connected to this rising acidity.”

When I interviewed Bill Taylor from Taylor Shellfish in Shelton a few months back for my Salish Sea series, he confirmed they’re having problems with larval oysters as the pH of Puget Sound drops. Just last summer researches at U-Dub announced that parts of  Puget Sound are significantly more acidic than is normal for sea water.

But what’s new in the Oceana report is that they’re finding other impacts in addition to the shell issues. An example: some fish, like salmon, use their sense of smell to navigate. Apparently, acidic water messes up some fishes' sense of smell, and makes it hard for them to find food, avoid predators and locate themselves on a reef.

The report does say a more acidic ocean isnt all bad news; it says algae and jellyfish may actually do better.