Though polls show more Americans believe the planet is warming, the issue is seldom discussed on campaign trail.

Washington, DC – Weather experts say 2012 is set to be the warmest year on record in the United States.

Meanwhile, a new poll conducted by the Pew Research Center found a growing percentage of Americans – two-thirds – believe there is solid evidence that global warming is happening.

Climate change enjoyed a brief moment on the national stage in August: at the Republican Party’s national convention, presidential nominee Mitt Romney mocked what he said was President Barack Obama’s “promise to slow the rise of the oceans – and to heal the planet. My promise is to help you and your family.”

A few days later, Obama retorted that “climate change is not a hoax. More droughts and floods and wildfires are not a joke. They are a threat to our children’s future”.

Aside from that exchange and cursory mentions, however, the issue has been notably absent from the campaign trail, leading climate change writer Joe Romm to dub global warming “the Voldemort of the Obama Administration: the threat-that-must-not-be-named”.

For the first time since 1984, climate change was not asked about at any of the presidential debates – although environmental groups submitted 160,000 petitions to Jim Lehrer, the moderator of the first presidential debate, urging him to broach the subject.

In 2008, by contrast, Obama and Republican nominee John McCain often mentioned climate change.

McCain noted in his second debate with Obama that year that he had “disagreed strongly with the Bush administration” on climate change, and suggested setting up a cap-and-trade system to reduce greenhouse gas emissions by 60 per cent by 2050.

Obama was also a vocal proponent of a cap-and-trade system, which would set up a government-run market for permits to emit greenhouse gases like carbon dioxide. A cap-and-trade bill passed the House of Representatives in 2009, but it died in the Senate amid stiff opposition.

The great bifurcation

There have long been climate change doubters, but over the course of the past decade a distinct partisan split has emerged, with Republican voters growing increasingly sceptical.

In 1998, about one-third of Republicans said news of global warming was “exaggerated”, according to pollster Gallup. Today, two in three Republicans say the same thing. (The comparable figure for Democrats ticked down slightly over the same time period, from 23 per cent to 20 per cent.)

Megan Mullin, an associate professor of political science at Temple University, co-authored a study published earlier this year showing that local variations in temperature affect public opinion on global warming.

But the two biggest factors influencing whether a given person believes the planet is warming are party identification and ideology – with Democrats and liberals more likely to believe and Republicans and conservatives less likely. Those two factors, Mullin told Al Jazeera, “drown out almost everything else”, such as age and education level.

‘Off on the horizon somewhere’

In 2010, as the US was pulling out of a sharp recession, the conservative Tea Party movement spearheaded a Republican victory in midterm elections, winning control of the House of Representatives. Moderate politicians from both parties were defeated by right-wing insurgents.

Among the casualties were two congressmen from conservative-leaning districts: Rick Boucher, a Democrat from Virginia who voted for the cap-and-trade bill, and Republican Bob Inglis of South Carolina, who voted against it but supported action on climate change.

Inglis now heads the Energy and Enterprise Initiative, a campaign proposing conservative climate solutions such as a revenue-neutral tax swap, which would impose taxes on burning fossil fuels but cut other taxes, such as those on income.

He believes there are two main reasons why Republicans have become more sceptical of climate change science. The recession that began in 2008 “caused us to focus on this month’s mortgage and this month’s paycheck”, he said, as opposed to climate change, which many see as “off on the horizon somewhere”.

Inglis also blames Democrats’ support for a cap-and-trade system. Conservatives, he says, “hear ‘cap’ and they think regulators, and they hear ‘trade’ and they think complexity”. As a result, he thinks some Republicans decided to “say well, alright, let’s just stay away from this for now”.

For his part, Michael Mann, a climatologist best known for his role in developing the “hockey-stick graph” showing a recent spike in global temperatures, charges well-funded efforts by groups funded by the Scaife Foundations and the billionaire Koch brothers with “eliminating politicians within the Republican Party who show any interest in actually having a faithful discussion about climate change”, such as Inglis.

Now, he laments, “one of our two major parties has largely been purged of anyone who is willing to recognise that climate change is not a hoax. … I think that’s a big part of the problem”.

This year’s Republican presidential candidates reflected this shift: only former Utah governor Jon Huntsman Jr – and, to a lesser extent, Romney – said they believed human activity contributes to climate change.

Huntsman mocked the climate scepticism of many in his party when he tweeted in August 2011, “I believe in evolution and trust scientists on global warming. Call me crazy.” But he exited the race early after disappointing showings in the primaries.

Although Romney recently stated he believes “that the world is getting warmer” and “that human activity contributes to that warming”, he hedged that “there remains a lack of scientific consensus on the issue” and opposes both a carbon tax and the cap-and-trade approach.

Democratic hesitance

“I think [Democrats are] fearful that there’s so much money on the other side that they’ll lose the fight anyways.” – Climate scientist Michael Mann



Republicans’ lack of talk on climate change is understandable – it’s anathema to much of their base.

But what about Democrats? If recent surveys are to be believed, climate change could be a winning electoral issue: one poll found undecided voters are about as likely as pro-Obama voters to say the president should do more to address climate change.

Another survey, conducted by a polling outfit affiliated with the Republican Party, discovered that a majority of hunters and fishermen – who tend to vote for conservatives – want the government to do more to reduce greenhouse gas emissions.

So why have Obama and many other Democrats largely kept mum?

Mann – who pointed out that Obama has made some climate change achievements, such as stricter emissions limits for coal-fired power plants and automobiles – said he thinks there is a “timidity” among Democratic politicians to address climate change. “I think they’re fearful that there’s so much money on the other side that they’ll lose the fight anyways,” he told Al Jazeera, “and [that] they will lose political capital in the process of trying to fight that fight”.

Some Democrats – especially those representing conservative areas – may worry that support for action on climate change could lead to their political demise. In the run-up to the 2010 midterm elections, for instance, West Virginia Governor Joe Manchin – fighting for a Senate seat – released an ad in which he literally shot at cap-and-trade legislation.

And although a broader section of the American public may be concerned about climate change, it’s far from their number-one issue. In September just two per cent of Americans cited the environment as the most important problem facing the country, according to Gallup.

That’s compared to the almost three-quarters of voters who say the economy is the biggest problem. Because some assume that economic growth and environmental protection are inherently at odds with one another, politicians may be reluctant to speak up for fear of losing votes.

After the second presidential debate, moderator Candy Crowley explained why she didn’t ask about climate change: “I had that question for all of you climate-change people. We just, you know, again, we knew that the economy was still the main thing, so you knew you kind of wanted to go with the economy.”

Inglis mentioned that media magnate Rupert Murdoch tweeted in July that climate change is real, but that “so far all cures worse than disease” – presumably referring to the economic effects of reducing emissions.

Murdoch’s comment “encapsulates the thinking” on climate change, Inglis said. “And so our challenge is to say hey, we’ve got a cure to this that’s not worse than the disease.”

Communication

“Isolated days of abnormally high or low temperatures leave no permanent trace on public opinion as they recede into the past.“ – Patrick J Egan and Megan Mullin



Compared to many other environmental issues, global warming is diffuse and intangible. “There’s no one cause, and there’s no one place where it’s happening,” said Chris Mooney, who has written several books on science and politics.

Politicians concerned about climate change need to do a better job communicating with voters about the science, argues Mooney. “If they lead with the very cautious message that we can’t attribute any one [weather event] to climate change, which is true,” he said, “then they’re undermining themselves”.

There are other, more effective ways of communicating about global warming, he said, while still respecting the scientific nuances. One trope is the “dice-loading” analogy, the idea that climate change increases the likelihood of extreme weather events.

Rising temperatures in and of themselves, however, will likely not be enough to convince the public of the need to take action. “Attitudes on global warming shift as rapidly as the weather,” Mullin’s study discovered. “Isolated days of abnormally high or low temperatures leave no permanent trace on public opinion as they recede into the past”.

Follow Sam Bollier on Twitter: @SamBollier