"Scientists warn the planet is facing a global climate crisis that could result in unprecedented sea-level rise, drought, and food shortages," says Andrew Restuccia at Politico. "But you wouldn't know it from listening to the presidential debates." For the first time since 1988, neither candidate or their running mates talked about climate change or global warming in any of their four face-offs, and none of them were asked about it. The topic is also largely absent from the campaign trail: President Obama only occasionally brings it up, preferring to talk about the promise of green energy, and Mitt Romney only talks about climate change as a way to criticize Obama's policies. In September, the candidates told a group of science organizations that they believe that the earth is getting warmer, thanks in part to human activity, and that this is a big problem. So why is neither one talking about the issue?

1. All the solutions are politically toxic
It's safe enough to agree that the changing climate is a real problem, but "the two most effective ways of reducing global warming pollution — taxing it or regulating it — are politically toxic in a year when economic problems are paramount," says John M. Broder at The New York Times. The Senate let a cap-and-trade bill die in 2010, in large part because "the Republican Party has essentially declared climate change a nonproblem." And it's harder to push for solutions given "a well-financed long-term campaign to sow doubt" about the scientific consensus that humans are responsible for rising temperatures. In short, there's little political upside to talking about climate change.

2. Voters like being in denial
"The easy answer is that it's not good politics... to talk about emissions when voters are worried about jobs," but that's missing a key point, says Laurent Belsie at The Christian Science Monitor. Polls actually show that Americans are increasingly convinced about the science of man-made global warming — "the ranks of the 'climate deniers' are thinning, albeit slowly" — but they also understand that there are no easy solutions. That makes global warming feel like "something to fear because we can't fix it." So if Obama and Romney aren't talking about the problem, maybe it's "because we really don't want to hear" about it.

3. It's all about Ohio, stupid
It's been clear for some time that the swing state of Ohio could well decide the election — now it is the must-win state — and one of the keys to winning the Buckeye State is performing well in a "stretch of southern and southeastern Ohio where Democrats long held the allegiance of working class voters tied to the coal industry," says Nate Cohn at The New Republic. "The so-called 'war on coal' is a pocketbook issue" there, and Romney needs to talk it up to overcome Obama's advantages in other parts of the state. Obama has been hitting back by noting Romney's own anti-coal rhetoric from years past. That's left us with "the kind of bizarre reversal that only an election can cultivate," says Stephen Lacey at Think Progress, where both candidates "have run ads attacking the other for their previous comments on the need to transition away from coal."

4. Romney and Obama are letting surrogates make their case
"Every green group in D.C. has now pointed out 20 times apiece" this lack of talk about sustainable energy and climate change in this election, says Brad Plumer at The Washington Post. But "fortunately, there's a second-best solution for those who still want to hear more from the campaigns about this issue." In early October, E&E News and the MIT Energy Initiative hosted a wide-ranging discussion between energy advisers to Obama and Romney. It's "too bad that we couldn't get the actual candidates involved in a discussion like this," but if you want to know more about their policies on climate change, at least you can watch the surrogate face-off or read the transcript.

Read more political coverage at The Week's 2012 Election Center.