Environmentally speaking, the companion to energy policy has to be climate policy. We've already briefly looked at the energy policies of Barack Obama, Mitt Romney, and Green Party candidate Jill Stein—with the greenest by far going to Stein. Let's now take a quick look at the climate policies of each, plus those of Libertarian candidate Gary Johnson.
Skeptical Science has done a great job of looking at the implications of both Obama's and Romney's proposed policies, so let's start there.
Obama Offers Climate Progress, But Not Enough
After highlighting President Obama's efforts to increase vehicle efficiency (perhaps his single greatest environmental victory), Skeptical Science concludes:
President Obama's policies have been quite good with regards to greenhouse gas emissions. His climate policy has been similar. The USA did seem to put forth a good effort at the Copenhagen international climate conference, President Obama's Environmental Protection Agency (EPA) has begun regulating greenhouse gas emissions, and he would have signed a national carbon cap and trade system into law, had it not been blocked in the Senate.
However, President Obama has very rarely mentioned the words 'global warming' or 'climate change' in public. While his policy on the issue has been quite good, his leadership has not.
Mitt Romney Would Speed Us Towards Climate Catastrophe
In contrast, Mitt Romney's proposed policies focus almost exclusively on increasing domestic fossil fuel production (which is already at a high point under President Obama) and rolling back fuel efficiency standards:
A word count reveals that Romney's plan mentions the word "oil" 154 times, "climate" zero times. And during his prime time presidential nomination acceptance speech, his only mention of climate change was to mock President Obama for promising to try and slow sea level rise...In answering a question about climate policy, Romney repeated the myth that carbon pricing will harm the economy and tried to shirk American responsibility by focusing on China's emissions (more on China below). Most recently, in an interview on Meet the Press, Romney said, "I’m not in this race to slow the rise of the oceans or to heal the planet."... Romney's plan would not only result in a failure to result in a reduction of greenhouse gas emissions, [it] would stomp on the accelerator, sending us hurtling ever faster towards climate catastrophe.
Stein Campaign's Climate and Energy Proposals Solidly Dark Green
The greater contrast, and the greenest expressed climate policy—albeit one currently expressed quite briefly in campaign materials—comes from the Green Party's Jill Stein.
The Stein/Honkala campaign proposes creating, "a binding international treaty to reduce atmospheric carbon dioxide to levels deemed sage by scientific analysis to reduce global warming."
To be fair, if only in rhetoric the Obama administration has always claimed to be working towards a similar goal in international climate negotiations. However, its actions, constrained in large part by domestic political interests and Republican obstructionism, have fallen well short of what's scientifically required.
Stein's proposed energy policies, should they actually be implemented by surmounting the same domestic political constraints, are right on the mark towards making big reductions in greenhouse gas emissions. Stein proposes phasing out entirely coal use and halting the Keystone XL tar sands pipeline. She also proposes putting the nation on a trajectory to be 100% powered by renewable energy by 2050. It's this sort of ambition and action required to actually avert the worst of climate change, both now and in the future.
Libertarian Platform Off in the Brown Weeds
A brief end note on Gary Johnson, the Libertarian candidate for president: Johnson's views on Energy and Environment are classically libertarian. He says:
Cap and Trade schemes, tax subsidies, and government efforts to steer us to one energy source over another are inherently inefficient, disrupt the market, and ultimately impose costs we cannot afford. No where in the Constitution is the government given the power to manipulate our behavior as consumers or producers of energy.
That externalized costs of pollution from fossil fuels is one of the greatest market disruptions in modern economic times, and that efforts to place a price on carbon would go a long way to correct that (properly constructed), seems lost on Johnson.
That they would impose costs we cannot afford is clearly a value judgement of the sort Johnson then condemns:
Insisting on a basic cost-benefit analysis for regulations will restore an appropriate balance and common sense to environmental policy. Much of what government does in the name of environmental protection is really an effort to impose values on property owners, consumers and individuals.
That existing cost-benefit analyses on climate action versus climate inaction come solidly down on the side of acting as quickly as possible so as to avert even more costly action and consequences in the future is equally lost on Johnson.