Replacing your old incandescent light bulbs with compact fluorescents is a great idea. So is buying a hybrid car. But the single most important thing we can do to fight global warming is elect the right leaders. And while we need to think globally, it's time to act locally.

According to the Yale Center for Environmental Law and Policy, 83 percent of Americans now view climate change as a serious problem. Nearly two-thirds of us believe our country is in as much danger from global warming as it is from terrorists. Most of us think we should play a role in making things better, and we can - by making our homes more energy-efficient and by taking mass transit.

The kind of broad, sweeping change we need, however, is beyond the scope of you and me as individuals. What we need is leadership from our politicians to make a serious investment in alternative energy, make steep cuts in greenhouse gas emissions and take better care of our natural resources. Many of the key issues, such as mileage standards, are best addressed on a national level, but consensus is hard to reach with a divided Congress and with a president who has been in denial of the threat of global warming.

We can't be looking to the federal government alone - there are countless ways that local and state governments can step up and make a difference. Look no further than Mayor Michael Bloomberg and PlaNYC, the kind of comprehensive commitment to sustainability that we need. But what happens when the mayor leaves office at the end of 2009? Will his successor and the next generation of City Council members take PlaNYC forward or relegate it to the political trash heap?

Now is the time to build a coalition of eco-voters who put sustainability at the top of their issues list and demand that their elected officials do the same. If politicians do right by the environment, let's give them our support. If not, let's recycle them into another line of work. When it comes to global warming, every minute is a chance for elected officials to act. If they don't, we should - at the voting booth, because the climate-change clock is ticking for all of us.

--Ken Fisher is chairman of the NYC chapter of the New York League of Conservation Voters and a partner at law firm WolfBlock.