Whether you've seen Al Gore's film or not, you probably know by now that the carbon-based energy system we built last century is royally messing up our planet's built-in thermostat -- promising all kinds of nasty consequences unless we kick our response into high gear. What you may not know -- as scientists only recently broke the story -- is that carbon dioxide is doing something else pernicious to our planet apart from changing the chemistry of our atmosphere and destabilizing our climate: it is also changing the chemistry of our oceans and making them more acidic...Thirty percent more than preindustrial levels, according to an IHT op-ed this week by Thomas E. Lovejoy. If we don't kick our carbon habits, our oceans will be more acidic by century's end than they've been in millions of years.

Common sense tells us that probably not a good thing. And scientists confirm that it is bad news for marine life and for us humans who depend on it. Coral reefs, dubbed our ocean's rainforests because they support so much life, won't be able to grow when water is too acidic. Neither will countless other shell-building creatures that play crucial roles in big food chains.

In an age of staggering technological and scientific advances, many will find this news humbling: the more we learn about our planet, the more we realize how much is yet to be learned. But the ocean acid problem is also yet another major wake-up call that it's time to stop tinkering, as Time Magazine recently put it, with "the knife-blade margins within which life can thrive" on the only known habitable planet in our universe.

The good news is that the responses needed to stop the ocean acid problem are fundamentally the same as those required to stop global warming: in short, we (especially the U.S.) need to ramp up dramatically efforts to jump-start the global transition to a clean energy future. Shamefully, the U.S. federal government continues to dither despite good bipartisan proposals like the one offered by John McCain and Joe Lieberman. But fortunately, American citizens, cities, states, businesses, and farmers are busy actually doing something to help. For some encouraging examples, check out the Chicago Climate Exchange, Local Governments for Sustainability, The Climate Group, 25x25, and the Stop Global Warming Virtual March.

P.J. Simmons is Director for Strategy and Programs at the Sea Studios Foundation and co-editor of U.S. in the World: Talking Global Issues with Americans.