When we think about urgent threats to our environment, the images which come to mind are usually smokestacks and automobiles belching exhaust and smoke into the sky. But much of that pollution–the carbon that billows into the atmosphere from cars, power plants and other smokestack industries–doesn’t stay there. Much of it is absorbed by the oceans, where it becomes carbonic acid, with effects potentially as catastrophic as those of global warming.
At abnormally elevated levels, carbonic acid lowers the natural pH of our oceans. That in turn decreases the available calcium carbonate essential for forming fish bones, shells on crustaceans, and coral reefs. For example, we are now seeing early signs of damage to pteropods, the tiny shelled creatures which are the essential food of young salmon. So decline in pteropod numbers means decline in the salmon population. The effects of the addition of CO2 to the ocean ripple across many species, including human beings who rely on the sea for both food and economic survival.