WASHINGTON — Four years ago in New Hampshire, campaigning for the Republican presidential nomination, John McCain said to voters: “I do agree with the majority of scientific opinion, that climate change is taking place and it’s a result of human activity, which generates greenhouse gases.”
He made global warming a key element of every New Hampshire stump speech.
This week in New Hampshire, the governor of Texas and newest presidential contender, Rick Perry, said scientists have manipulated data to support their “unproven” theory of human-influenced global warming. He said increasing numbers of scientists have disavowed the theory altogether.
This is not simply a case of two very different politicians saying two very different things. The political discussion about global warming has lurched dramatically in four years — even as the scientific consensus has changed little.
McCain’s 2007 description remains the scientific consensus: Human activity, including the burning of fossil fuels, is pumping carbon dioxide and other greenhouse gases into the atmosphere and warming the planet.
But that scientific conclusion has become a political debating point. Joining Perry on the skeptical side, for example, is Rep. Michele Bachmann, R-Minn., another presidential candidate, who suggested Wednesday that “manufactured science” underpins what a questioner called the “man-made climate change myth.”
The nominal GOP front-runner, Mitt Romney, drew conservative fire when he said in June that he accepts the scientific view that the planet is getting warmer and that humans are part of the reason. Former Utah Gov. Jon Huntsman on Thursday tweeted: “To be clear. I believe in evolution and trust scientists on global warming. Call me crazy.”
“Climate change has become a wedge issue,” said Roger Pielke Jr., a University of Colorado professor who has written extensively on the climate debate. “It’s today’s flag burning or today’s partial-birth- abortion issue.”
Historically, climate change has ranked near the bottom of issues that voters care about as they evaluate presidential candidates. It failed to be a factor in the 2008 presidential race either in the primary season or in the general election. The major parties’ nominees endorsed the scientific consensus and thought the government should curb carbon emissions.
Even as it appeared that the government might take action on climate change, the political opposition intensified.
President Barack Obama favored a nationwide system in which industries would have to cap their carbon dioxide emissions and trade pollution allowances with one another. The then-Democrat-controlled House passed this “cap-and- trade” system in June 2009, but the plan stalled in the Senate after Republicans and major industries criticized it as a “cap- and-tax” system that would escalate energy costs.
The battleground shifted to the Environmental Protection Agency, which in December 2009 determined that greenhouse gases pose a threat to public health and welfare. That “endangerment finding” paved the way for regulating carbon dioxide as a pollutant under the Clean Air Act. GOP lawmakers and industry groups fought the plan, calling it a job-killing tax and an example of government overreach.
Some in the Tea Party seized on the issue as a rallying cry in last year’s election, which brought dozens of new members to Congress who reject a connection between human activity and climate change.
