Last week, President Obama asked Twitter users to send him questions about climate change, and Twitter users were happy to oblige. Some needled him about his support for Arctic oil drilling, others complained about climate-change deniers, and one asked him to deal with student-loan debt instead. He did his best to keep up, explaining that Arctic oil drilling is happening whether we like it or not, so we might as well set the highest possible standards, and from there the conversation devolved into a debate about the NBA Finals.

In contrast, if you press Republican presidential candidates like Marco Rubio or Carly Fiorina on climate change, they just scoff. "Our climate is always evolving, and natural disasters have always existed," says Rubio, which is a bit like saying cigarettes aren't harmful because people have always died of cancer.

"Companies shouldn't cave in to the demands of climate-change scientists," says Fiorina, probably hoping that nobody will point out that she nearly destroyed the last company she led.

None of the other Republican candidates can be bothered to worry about the gradual destruction of the planet, either. That may just be shrewd political calculation, since it seems most voters simply don't want to hear about climate change.

According to a March survey from Gallup, only about 2 percent of Americans say that the environment or pollution are the most important problems facing the country. Among voters who are concerned about the environment, issues like smog and endangered species tend to elicit more concern than the broader problems of climate change itself. In other words, it's easier to feel bummed out about African lions going extinct in our lifetime than the water wars that will take place after we're dead.

News networks are complicit: According to Media Matters for America, only MSNBC spent more than a few minutes talking about climate change during the 2012 election. Hey, the potential destruction of all life on Earth is a big story, sure, but it's so complicated and it's kind of a bummer! Better devote another hour to whatever the hell the Duggars are!

Worryingly, Hillary Clinton's campaign hasn't made much noise about climate change, either. She's definitely saying more than her Republican opponents, to be fair. She supports the reduction of power-plant emissions under the Clean Air Act; her campaign chairman, John Podesta, was previously a climate-change adviser for President Obama; and she doesn't try to pretend that nobody could possibly understand the science. "Sea levels are rising; ice caps are melting," she says. "If we act decisively now, we can still head off the most catastrophic consequences."

Oh, but wait—former secretary of state Clinton also supported Gulf Coast oil drilling and gave a thumbs-up to fracking overseas. Under her leadership, the US State Department colluded with energy companies to expand fracking operations in other countries, the facts of which were disclosed later by WikiLeaks. It would be nice to believe that this was secretly a form of clever espionage (we'll weaken hostile foreign powers by causing earthquakes in their countries and setting their tap water on fire!). But the Clinton Foundation also raked in millions of dollars from oil conglomerates, so it's more likely just a case of millionaires doing favors for millionaires.

And when it comes to the Keystone XL pipeline, she's adopted a stance not unlike her Republican adversaries: clamming up. "You won't get me to talk about Keystone because I have steadily made clear that I'm not going to express an opinion," she told an audience a few months ago. Oh okay! That settles that! Guess we'll just talk about something else then!

Here's why presidential rhetoric on climate change is so important: Local jurisdictions depend on federal support to prevent and prepare for climate disasters. For the last seven years, cities all over the country have been gobbling up millions of dollars in grants to prepare their infrastructure for floods, droughts, storms, and blackouts. Under the Obama administration, agencies like the Environmental Protection Agency and the Department of Transportation have managed to cut a lot of red tape on projects ranging from reducing car dependency to keeping seawater out of reservoirs.

Seattle, for example, got $6.1 million from the Department of Energy that helped pay for various climate-related projects, such as the distribution of water-saving showerheads and weatherization of low-income homes. Seattle's Center City protected bike lane project got $5 million from the federal government. The Seattle Streetcar Broadway Extension project got $10 million. The city also received technical assistance with energy audits of Capitol Hill Housing units.

The city's also working on projects to increase storm-water storage, so we don't wind up having to kayak to work through downtown. Other ongoing projects: modeling future energy needs to prevent blackouts, building storm-monitoring stations, creating a food distribution plan in the event of climate disaster. All of these projects could benefit from federal help.

But that help could go away—or at least be harder to come by—if the next president's official position is "climate shmimate." It's hard to predict exactly how that federal support to local jurisdictions would change under, say, President Jeb Bush. We know he's a denier ("It is not unanimous among scientists that it is disproportionately man-made," he said in 2011), but would he leave federal aid to communities intact? Or cut it a little? Or copy Florida's insane policy and ban any mention of climate change? There's no way to know, in part because he simply hasn't indicated what his plans are. And why would he, if voters don't care either way?

Getting the candidates to talk about climate change would require either a complete reversal of voter priorities—perhaps triggered by some catastrophic meteorological disaster, which sure would be fun—or pressure from special-interest groups. Of those two options, the latter involves far less loss of life and limb and is already under way: Last week, the California State Parent Teacher Association adopted a resolution urging schools to add climate change to existing curricula.

"Children represent a particularly vulnerable group already suffering disproportionately from both direct and indirect adverse health effects of climate change," the PTA wrote.

As forces for political change go, an angry mob of teachers is probably preferable to another Hurricane Katrina. But which do you suppose would be more effective? Hell will likely freeze over before Rand Paul deigns to respond to a strongly worded letter from the California PTA. And even then, he'd probably chalk up the freezing over of hell to natural causes.