"WE'RE COOKED, RIGHT?" I was talking to an old friend about global warming, and the fear he voiced is one many people share: that it may be too late to do anything meaningful. It's a reasonable anxiety. No one knows where our climate's tipping point lies, and if it's not already too late, it may soon be.

"It's too late" has become Big Carbon's replacement for "Maybe there's no problem." The same people who turned global-warming skepticism into a minor industry now want to hustle us smoothly from denial to despair. Their strategy has been clear for at least the past decade: to delay action on climate change until it is too late.

But the past 18 months have offered phenomenal hope that we can turn things around. Within that period, the Sierra Club and our allies have blocked 59 proposed coal-fired power plants--about a third of what the utility industry was planning to build over the next decade--and we're going after almost all the rest. Nationally, carbon-saving fuel-economy standards for cars are increasing from 25 miles per gallon to 35, while states with half the country's auto sales have mandated the equivalent of 44 mpg--a prerogative presidential candidates of both parties support.

So in just the past year and a half, we have put in motion measures that will squeeze more than 850 million metric tons of annual carbon dioxide emissions out of the business-as-usual rut we had been in since 2006, which is almost 10 percent of what we have to accomplish by 2050 to curb climate change. And those figures don't count the benefits of state renewable electricity standards; new appliance efficiency rules; or the city, county, state, and regional global-warming policies springing up everywhere.

But what, people ask, about India and China? Their rapid, carbon-heavy development could easily swamp all the gains made in the United States. Last December at the climate talks in Bali, however, India and China strongly signaled that once the United States rejoins the world in addressing global warming, they are ready to do their part--if they can get the technological and financial assistance they need.

Even if the United States adopts the Sierra Club's plan to reduce CO₂ emissions from 2006 levels by 2 percent annually, cutting emissions 80 percent by 2050, and even if the rest of the world joins in, our climate has already been dangerously destabilized. We're going to need to prepare our communities for and protect ecosystems from at least modest levels of climate change.

That conversation is only beginning--but the Sierra Club has a crucial message of hope. If we truly want to stabilize the climate, we need to revive the productivity of the natural world. Acre for acre, restoring a wetland takes more carbon out of the atmosphere than anything else we know how to do. Wetlands can also absorb the irregular water runoff a warming world will experience; for cities like New Orleans and Calcutta, they are buffers against floods and hurricanes. California has been warned that it can't expect to store its water supply in the winter snowpack in a warming world, but Los Angeles could meet much of its water needs if permeable surfaces allowed rainfall to seep into aquifers instead of being sheeted off in concrete channels. Cities like Phoenix need to accelerate their shift to indigenous, less thirsty gardens. The U.S. Forest Service has to return to its original mission of managing forests as watersheds, not tree farms. And the only way to protect south Florida's drinking water from saltwater intrusion from rising sea levels is to keep lots of freshwater pushing down on top of its aquifers. That's what the Everglades used to do--and could do again, if the "river of grass" were allowed to function naturally.

The cheapest and most effective approach is to get Mother Nature to do the heavy lifting for us. After all, only plants can efficiently remove carbon dioxide from the air once it has been released. Every acre of native prairie, brackish wetland, tropical rainforest, coral reef, or sea grass bed we preserve or bring back is a deposit toward a stable climate and a better future. We've overdrawn our account for too long; it's time to put our natural capital back to work.

Carl Pope is the Sierra Club's executive director. E-mail carl.pope@sierraclub.org.

Photo by Lori Eanes; used with permission.