After that, though, things get harder. Trade-offs start emerging. Some are huge: How much risk will you put up with from a nuclear power plant? Others are aesthetic: Community resistance to windmills on a nearby ridge or shoal seems to be diminishing as the new energy calculus gets clearer. And some trade-offs are very personal: Would you be willing to eat a lot less meat? (By some measures, livestock production accounts for as much greenhouse gas as driving.) Or might you change your diet to eat close to home, forgoing those January strawberries from across the globe? Oh, and that overseas vacation? The jet to get you there will almost certainly burn more fuel than anything else you do all year.

The truth is, though, that none of these individual choices will add up fast enough to materially affect the amount of carbon in the atmosphere or the amount of oil left in the big fields of the Middle East. There simply aren't enough people paying real attention. The momentum of our economy is too strong, especially since we need change to come so quickly. Rajendra Pachauri, the head of the Intergovernmental Panel on Climate Change, who accepted the Nobel Peace Prize in 2007 alongside Al Gore, said recently that unless fundamental shifts were under way by 2012, the feedback loops driving climate change would take on an irrevocable life of their own. In the United States, 2012 means this President, most of these senators. It means us.

Given that time frame, only two things could radically change our trajectory. One is a World War II–scale commitment to technological change—almost literally as during World War II, in fact, except that this time instead of Detroit automakers shifting to tank and plane production, they start building plug-in hybrid cars and locomotive engines. And change wouldn't stop at the factories. If we're going to electrify the country's vehicle fleet, as Al Gore has proposed, we'll need a massively revamped transmission grid, one capable of bringing solar power from the desert Southwest and wind energy from the nation's midsection. It's not like the Apollo program, which focused all our technological prowess on three men. This is more like getting everyone to the moon. One bonus: This huge undertaking is the most promising stimulus for a limping economy. And it mostly has to be done at home. No one is going to put a house on a boat and send it to China to get insulated. Solar panels mean guys with hammers up on roofs.

Boosting technological investment is only half the answer. We also need to fix the set of economic incentives that drives our energy system, so that capitalism can go to work helping us solve the problem. Until now, free markets have made the problem worse, not better. That's because they get no signal about carbon: Since there's no cost to pour it into the atmosphere, there's no way for markets to work their magic. But an international treaty that capped the amount of carbon we could emit would, in effect, put a price on CO2, one high enough to reflect the damage it's doing. (Some experts have called for an oil depletion tax on every barrel of oil as well, using the funds to prepare us for the post-petroleum future.) Both candidates for President last fall supported some form of a cap on carbon emissions, which would have the effect of driving up the price of coal and gas and oil and hence driving down demand. We know this strategy works. It's why when oil prices spiked last year Americans suddenly started driving less almost for the first time in our history. But it's also politically painful, especially in the current economic downturn. To give it any chance of passage, you'd need to figure out how to rebate directly to taxpayers the money you collected from selling the permits to pollute, a strategy that President Obama embraced in his campaign.