When it comes to the environment, the presidential contest has offered sharply contrasting images: Barack Obama posing beside an Iowa wind turbine and Mitt Romney standing in front of an Ohio coal mine.
But in their rhetoric, both candidates have focused on a similar theme – sustainable development, the notion that the private sector can work with government to protect the environment while boosting the economy and creating jobs.
The pro-business focus has disappointed some ardent environmentalists. Obama, for example, has been criticised for not cracking down on the controversial technique of hydraulic fracturing, or fracking, which uses chemicals and water to blast through underground shale formations.
Romney's recently unveiled energy policy focuses on industry optimism about drilling in underground shale deposits for domestic oil and natural gas. Romney's supporters include the billionaire Koch brothers, who made their fortune in oil, gas and chemicals.
The big question is whether any of their environmental rhetoric will matter when voters go to the polls.
Despite withering temperatures and a widespread drought, the race for the White House barely has a tinge of green.
"While this year's wild weather has caused alarm, it has so far not raised environmental issues on the public agenda," said Karlyn Bowman, who tracks public opinion at the pro-business American Enterprise Institute. "There's no evidence that it will be a big issue nationally."
The environment trails far behind the economy and jobs as a pivotal concern for U.S. voters, which has been the case in the last few presidential elections, Bowman said.
Wind, solar and energy efficiency
On the issue of climate change, both Obama and Romney have expressed their belief that climate change is occurring and that human activity contributes to it, a shift for Romney who once said he was uncertain.
Obama has dubbed climate change "one of the biggest issues of this generation" in an online discussion with scientists. Romney has voiced his view that unilateral US action to curb greenhouse gases would "shift industrial activity overseas" to countries with less stringent environmental laws.
Obama's campaign touts the president's commitment to decrease US foreign oil dependency by promoting renewable energy sources including wind, solar and geothermal. It notes that US electricity generation from solar power has more than doubled since Obama took office in 2009.
The campaign also promotes new energy efficiency rules that would boost mileage for cars and light trucks to 54.5 miles per gallon by 2025, nearly twice the 2009 level. The campaign website (here) features a video on Obama's "all-of-the-above" energy strategy, with a mix of renewables, oil, natural gas, biofuels, nuclear and fuel efficiency.
Republicans have seized on the administration's failed investment in Solyndra, the solar panel company that went bankrupt after receiving $535 million in government loans.
And Obama's approval of offshore oil leases in the environmentally sensitive Arctic Ocean has raised alarm among his ecologically minded supporters.
"Obama is pushing to drill the Arctic Ocean, where climate change is having a disproportionately severe impact," Peter Van Tuyn, an Alaska-based environmental attorney, said. "This is a risky project that flies in the face of science and common sense."
Romney and the Republicans, Van Tuyn said, feel compelled to play to Obama's right, "and thus think that even more drilling of the Arctic is the answer."
Obama's philosophy of promoting a variety of energy alternatives is similar to one pitched by Republicans in 2008 in response to record-high gas prices. They have continued using it, even as Obama adopted it to push back at critics claiming he favored clean energy technology over traditional fuels like oil and gas that emit climate-warming carbon dioxide when burned.
A recent white paper called "The Romney Plan For A Stronger Middle Class: Energy Independence," is long on energy development: state control of energy development on federal lands within their borders, opening offshore areas to drilling, changes in regulation and easing of private development of new technologies.
The document says this will create more than 3 million jobs, spark an economic resurgence and lower energy prices. It does not assess the plan's environmental impact.
The environment's limited role in the current campaign may be a sign of how the issue has evolved over more than a century, said Steven Cohen, executive director of The Earth Institute at Columbia University.
Before the environment surfaced as an issue, there was a push to protect nature, as exemplified by Teddy Roosevelt's creation of the US Forest Service and the national park system. By the 1970s and 1980s, Cohen said, that push had shifted to health and safety concerns about toxins in US air, water and soil.
Now, he said, "The environment's being treated as an economic development issue ... so we have to figure out a way to run the global economy in a way that doesn't poison us."