Are you wondering like me how climate change could fail to be a substantive issue in this year’s presidential campaigns?

One explanation may be the unwillingness of debate hosts to raise the issue. Early this year, the League of Conservation voters released an analysis of the debates in 2007 moderated by hosts of the top political programs on television and found that only 24 questions related to climate change or global warming were asked out of a total of 2,275 questions. I haven’t seen an updated analysis of debates since the first of the year. The debates are (or were) a significant source of campaign news; if an issue isn’t raised in a debate, it won’t appear in the next day’s media summaries.

Another explanation is that climate change, while worrisome to Americans, is not among our top concerns. Last year, polls indicated Iraq was top of mind for voters, at least among Democrats. This year it’s the economy, with health care remaining another huge issue. Among Republicans, immigration is a dominant topic. It appears the news media are taking their cue from polling results and covering the issues voters say are their greatest concerns. That relegates climate change to a non-issue in political coverage.

Yet another possible explanation surfaced this week in a post by Joe Romm, editor of Climate Progress (Romm once worked for the Clinton Administration). Citing Elizabeth Kolbert’s book, Field Notes from a Catastrophe, Romm writes: “How can the traditional media cover a story that is almost ‘impossible to imagine’? I don’t think they can.” One reason, he says, is it’s in the nature of the media to lose interest in a story after telling it over and over again. Climate change, because of its complexity and dimensions, is a story that must be repeatedly explored.

While Romm doesn’t refer specifically to political reporters, his analysis suggests the political media simply aren’t up to the task of covering the climate change story; heck, even one of the best climate reporters, Andy Revkin of the New York Times, is singled out for criticism by Romm. If Revkin can’t do justice to the story, certainly no political reporter can.

Revkin responds to Romm here.

Frankly, I think one could write the perfect story on global warming, or create the perfect documentary, and repeat it over and over, and still not see much movement if the goal is to rapidly shift society out of its coal-fired comfort zone as the world heads toward 9 billion people…

As I’ve said, an energy quest — from the bathroom light fixture to the highway to the boardroom to the classroom — does not begin in a newspaper, but must build from deeper within a society (with a big dose of nonpartisn (sic) leadership).

Revkin is right, of course: The news media can only do so much in moving society away from the brink of catastrophe. And leaders of all stripes (and I would add voters, too) must step forward to place climate change at the top of our political agenda and work to keep it there. But I also agree with Romm that the national media is showing no staying power with this story, which I believe to be easily the most important one of our time and will remain so for years to come. The media, like our politicians, must lead, even when the electorate has its mind on other things.

The good news is there’s still time to make global warming a core subject in this year’s presidential campaign — the general election remains eight months away. And the Democratic race is not over. In case you’re interested, here are Clinton’s and Obama’s energy and climate plans.