As if global warming weren’t bad enough: as this Oregonian story points out, rising levels of CO2 in the atmosphere are not only heating the climate, they’re making seawater more acidic—which in turn “could wreak profound changes on the diversity and productivity of oceans.”

It’s an interesting bit of scientific detective work. Some types of ocean plankton are apparently very sensitive to pH: their shells can’t form when the water grows too acidic. The oceans have been absorbing a lot of the CO2 that’s been emitted by fossil fuel burning, and higher levels of dissolved CO2 have raised the ocean’s acidity by 30 percent in the last century or so. The result: the plankton are getting squeezed out, especially from the cool northern Pacific waters that absorb the most CO2. Scientists predict that if CO2 levels continue to rise, the higher acidity could eliminate these plankton, along with shelled sea creatures such as the sea urchin, from polar waters sometime in the next century.

This sort of thing is as fascinating as it is disturbing—and it should serve as a reminder that, in subtle and often unpredictable ways, our fossil fuel consumption may wind up fraying the earth’s ecosystems over the coming century just as much as pollution and habitat loss did in the previous one.