The Obama administration’s signature climate policy—the Clean Power Plan, meant to prevent millions of tons of carbon-dioxide emissions from entering the atmosphere—was temporarily blocked last week by the Supreme Court.

The block is unprecedented, and it casts doubt on the ability of any president to mitigate climate change without help from Congress. (Though the plan may fare better in a now-reconfigured Court.)

But it doesn’t cast as much doubt on the future of American energy. U.S. greenhouse-gas emissions are already falling, thanks to cheap renewable energy, cheaper natural gas, and coordinated activism against coal. Last year, the United States pledged to the world that its 2025 emissions would be at least 25 percent lower than its 2005 levels—and, even without the Clean Power Plan, it could still keep that promise.

So the trends, if not the high court, favor Obama. But he also hasn’t yet lost the policy game. The White House is pushing forward many other regulations that will similarly restrict greenhouse gases. Some of them came out over the last year, and some are anticipated over his next year in office. Here’s a tour of some of the most important.

Air Quality

When measuring national ambient air quality, the Environmental Protection Agency pays special attention to five types of pollutant: ozone, mono-nitrogen oxides, sulfur dioxide, particulate matter, and lead. Outside of how they change the climate, all five of these can cause severe health problems. Ozone, for instance, irritates the lungs even in minuscule amounts, and higher levels of it are linked to increased emergency-room visits. It’s a major ingredient in smog—and, when low to the ground, it functions as a greenhouse gas.

Since 2007, the EPA’s scientific advisory board has recommended that the national ambient air quality standards require ozone levels to be very low, at 60 parts per billion. Finally, last fall, the EPA said it would set levels lower than ever, though they will still only require 70 (and sometimes 65) parts per billion.

This regulation won’t hit industrial plants and other polluting sources immediately. Instead, the EPA will require metropolitan and state governments to shift local industry so their region complies with the new standards. If the city doesn’t obey, the federal government will withhold highway funding.

(Ozone can confuse as a chemical: Isn’t the hole in the ozone layer a bad thing? Yes. To somewhat simplify science, when ozone is in the troposphere—that is, the part of the atmosphere that you and I inhale every day—it harasses plants and animals. When it’s in the stratosphere—the next layer up—it protects us from the sun’s ultraviolet radiation.)

Heavy-Duty Vehicles

Though President Obama has focused on climate in his second term, regulation from his first term may shape it just as much. In 2012, the administration enacted new fuel-efficiency rules that will double car-and-truck mileage per gallon by 2025. In fact, they may ultimately more than double it. Dave Cooke, a vehicle analyst at the Union of Concerned Scientists, told me that the greenhouse-gas reductions from these rules almost equal those of the Clean Power Plan.

This summer, the EPA and the Department of Transportation will finalize similar standards for heavy-duty vehicles. The rules will require tractor-trailers, vocational vehicles (like UPS trucks), and super-duty trucks and vans (like the Ford F-250) to almost double their fuel efficiency by the end of next decade. These rules will also be the first to require not just more efficient tractors, but aerodynamically improved trailers.

“In 2010, the average [heavy-duty] vehicle on the road was in the ballpark of between six and six-and-a-half miles per gallon,” said Cooke. “The best vehicles can now push up to seven. By 2027, the average new tractor trailer would get between nine and 10 miles per gallon.”

Semis produce about two-thirds of the greenhouse gas emissions from this class of truck. The nice thing about regulating their emissions, Cooke said, is that their mileage doesn’t significantly shift in response to changed fuel economics.

In light vehicles, about 10 percent of fuel-efficiency gains are lost to what Cooke called a “rebound effect.” If cars become 20 percent cheaper to drive, people use them two percent more than they would otherwise. But freight traffic responds much more to consumer spending than it does to lower fuel costs.

“You’re only going to see an increase in freight traffic if more people are buying goods that are shipped by a truck,” said Cooke. “These trucks aren’t driving around for fun.”

Remarkably, because over-land trucking is predicted to keep growing, these rules will only briefly limit emissions. Trucking emissions are expected to fall to 2013 levels and then stay static for two decades—before increasing again. “Even with this rule in place, they’re still looking out and projecting a net increase from this sector,” Cooke told me.


Unlike carbon dioxide, methane dissipates from the atmosphere fairly soon after being emitted. Its life can be measured in years, not centuries. But it traps heat about 25 times as efficiently as CO₂ does, so it is still a major source of short-term climate change.

The Obama administration seeks to limit methane in a few ways. First, the EPA is setting rules around how much methane can be emitted by all new oil and gas operations nationwide. The agency will direct companies to find and plug leaks in pumps and also to use capture gas released while drilling for wells.

Second, the Bureau of Land Management will limit how much methane can be “flared” by oil companies when they’re harvesting gas on public land, as often happens during fracking. While this rule only applies to natural-gas mining on public land (as opposed to the EPA rule, which applies everywhere), it’s much more stringent than what the EPA can do. It will also apply to new and old mining operations.

“The BLM can’t really promulgate a rule to try to reduce emissions. What they did was more related to capturing lost gas for U.S. taxpayers,” says Cheryl Wilson, an energy analyst at Bloomberg Intelligence. Meanwhile, the “EPA can go ahead and put out rules under the Clean Air Act really specific to air emissions.”

She said that emissions savings would be about equal between the BLM’s stricter but less broad rule and the EPA’s broadly applied but permissive one. Both agencies will finalize their rules by the end of the year.

Aviation Emissions

Last week, the International Civil Aviation Organization (ICAO), the UN agency that oversees passenger flights, arrived at the first binding limits on carbon dioxide emissions, according to The New York Times. The aviation industry moves slowly—manufacturers develop jets more than a decade before they enter commercial fleets—so the rules, which only apply to new planes, don’t kick in until 2028.

Once the ICAO finalizes the rules, the EPA will likely issue engine-efficiency rules which mimic the ICAO standard, says Wilson. The EPA warned the aviation industry last year saying that new rules were coming.

Some environmentalists say there are early signs these EPA rules won’t go far enough, and that it needs to do more than require engine efficiency.

“At this point, we know EPA’s moving toward regulating the aviation sector,” said David Babson, a fuel expert at the Union of Concerned Scientists. “Ultimately the EPA really will need to implement stronger standards than what ICAO has indicated.”

“Why aircraft are so different than cars is that one of the primary operating costs [for jets] has been fuel costs for a long, long time. There’s not enough efficiency to squeeze out there” to reduce carbon emissions, said Babson. He said the EPA should guide manufacturers to use alternative fuels and reduce the carbon intensity of pre-existing fuels. (“Carbon intensity” is a measure of how many emissions result from a certain amount of power.)

He also said he doubted the EPA would be able to finalize the efficiency rules before the end of 2016.

And Other Places Too

These are not the only rules that the Obama administration is working on. It’s adopted tighter rules for home appliance efficiency. Wilson said the new rules for air conditioners are especially important, because the number of new buildings with an AC unit is increasing. Obama has also required federal agencies to cut their greenhouse-gas emissions 40 percent by 2025.