I know we’ve been down this road before, but since it’s been a while, and in light of Bush’s emphasis on ANWR, it’s probably worth keeping a few details in mind that the president neglected to mention.

"Drilling in ANWR would likely produce only 3.2 billion barrels of oil, according to the U.S. Geological Survey, not even enough to satisfy six months’ demand; oil would not begin to reach the market for another 10 years; and it would take 50 years to extract the full amount. For this pittance, the House leadership and the administration are willing to disturb hundreds of acres of pristine wildlife habitat."

I’d just add that the NYT reported a while back that oil companies are now “largely uninterested in drilling” in Alaska’s Arctic National Wildlife Refuge, because “any oil from the refuge would meet only a tiny fraction of America’s needs.”

My hunch is, the White House wanted to a) look like they were offering a proposal to address the gas-price problem; and b) try to pin high prices on congressional Democrats. I’d be surprised if anyone really fell for this nonsense, but given the president’s enthusiasm, it’s worth setting the record straight.

I have to say that all the environmentalists I know -- and I tend to hang out with the climate crowd -- care about stopping global warming because of its impact on humans, even if they aren't so good at articulating that perspective. I'm with them.

The reason that many environmentalists fight to save the Arctic National Wildlife Refuge or the polar bears is not because they are sure that losing those things would cause the universe to become unhinged, but because they realize that humanity isn't smart enough to know which things are linchpins for the entire ecosystem and which are not. What is the straw that breaks the camel's back? The 100th species we wipe out? The 1,000th? For many, the safest and wisest thing to do is to try to avoid the risks entirely.

What the day -- indeed, the whole year -- should be about is not creating misery upon misery for our children and their children and their children, and on and on for generations. Ultimately, stopping climate change is not about preserving the earth or creation but about preserving ourselves. Yes, we can't preserve ourselves if we don't preserve a livable climate, and we can't preserve a livable climate if we don't preserve the earth. But the focus needs to stay on the health and well-being of billions of humans because, ultimately, humans are the ones who will experience the most prolonged suffering. And if enough people come to see it that way, we have a chance of avoiding the worst.

"These are issues worth discussing," said Shawn Lawrence Otto, chief executive officer of Science Debate 2008. "Because of the huge impact that science and technology is having on our lives and our policies, voters have a right to assess the candidates on these topics -- and candidates have an obligation to tell voters what they're thinking."

Science and technology are responsible for half of America's post-World War II economic growth, said Otto, but scientific primacy is shifting rapidly to Asia. "To maintain American economic strength going forward, we need to find a way to deal with that -- and the candidates have been virtually silent," he said.

An even larger issue is climate change, which has been identified by the global scientific community as an imminent and almost certainly catastrophic threat.

"Is there a greater moral imperative than the ongoing viability of the planet?" he asked. "Science is about practical solutions to moral questions."

Earth Hour won't suffer for a lack of gimmicks. Servers wearing glow-in-the-dark necklaces will sell eco-tinis at bars and restaurants in Phoenix. A local yoga house in Michigan will offer sessions by lamplight, and the Sheraton Hotel in Chicago will have check-in by candlelight. Watching the lights wink off in major metropolitan areas might look impressive, but it's worth asking: What's the point? As Roberts himself notes, the energy saved by turning off your lights for an hour "won't make an enormous difference." So, if it won't cut carbon emissions, why bother then with Earth Hour, or Earth Day or Earth Live, last year's daylong concert for the environment?

Because climate change is essentially a political problem, and the language of politics is symbolism. Just because an act is symbolic doesn't mean it empty.

"Resource wars" are things that happen elsewhere. We don't usually think of our country as water poor or imagine that "resource wars" might be applied as a description to various state and local governments in the Southwest, Southeast, or upper Midwest now fighting tooth and nail for previously shared water. And yet, "war" may not be a bad metaphor for what's on the horizon. According to the National Climate Data Center, federal officials have declared 43 percent of the contiguous US to be in "moderate to extreme drought."

Certainly, you've seen the articles about what global warming might do in the future to fragile or low-lying areas of the world. Such pieces usually mention the possibility of enormous migrations of the poor and desperate. But we don't usually think about that in the "homeland."

Maybe we should.