When countries gather in Paris next month to hammer out a new climate agreement, all eyes will be on the world’s major emitters. While the United States, world’s second-largest greenhouse gas contributor, has received criticism in the past for lackluster action, recent evidence shows that the country is ramping up its ambition—progress that will likely last well beyond Paris.

Tackling Climate Change with Progress Across Sectors

Earlier this year, President Obama formally announced the U.S. commitment to reduce its emissions 26-28 percent below 2005 levels by 2025. Throughout 2015, the administration has taken important and unprecedented actions in several sectors to help achieve this goal, including:

  • Power Plants: In August, the Environmental Protection Agency (EPA) finalized the Clean Power Plan (CPP), establishing the first national rules to limit CO2 pollution from existing power plants, the largest U.S. source of GHG emissions. EPA estimates the rule will cut power sector emissions 28-29 percent below 2005 levels by 2025 and 32 percent by 2030. If states take full advantage of cost-effective opportunities in energy efficiency and renewable energy, the country could go even further in reducing power sector emissions.

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  • Heavy-Duty Trucks: In June, EPA and the National Highway and Traffic Safety Administration (NHTSA) proposed a second round of fuel efficiency standards for medium- and heavy-duty trucks. These standards are estimated to save about 1 billion metric tons of GHG emissions, which is equivalent to the annual emissions from more than 210 million cars.

  • Aircraft: In June, EPA took the first steps toward addressing GHG emissions from airplanes by issuing an advanced notice of proposed rulemaking, setting the stage for future development of a carbon dioxide emissions standard for commercial airplane engines.

  • Buildings: The Department of Energy (DOE) finalized several new efficiency standards for appliances and other equipment. Its recent agreement with industry and energy efficiency advocates to set new standards for commercial rooftop air conditioners is poised to be the biggest energy saver in DOE’s history.

  • HFCs: In July, EPA finalized rules that will reduce emissions of hydrofluorocarbons (HFCs), potent greenhouse gases commonly used as refrigerants and for other industrial uses. EPA estimates these rules will avoid emissions equivalent to 54 to 64 million metric tons of CO2 in 2025 (equivalent to the annual emissions from 11 to13 million cars). And in October, EPA proposed a rule that will help capture, reclaim and recycle more HFCs from existing equipment , which will prevent about 7.5 million metric tons of greenhouse gases.

  • Natural Gas Infrastructure: In August, EPA proposed its first-ever rules targeting methane emissions from the oil and gas sectors, expected to reduce emissions by 8.5-10 million tons in 2025.

  • Landfills: In August, EPA proposed methane emissions standards for new landfills and guidelines for existing landfills. Together, EPA estimates these proposals will reduce GHG emissions by 12.2 million metric tons in 2025.

These Actions Will Likely Have Staying Power

There are several reasons why these actions—especially the Clean Power Plan—are likely to live on through Paris and after President Obama leaves office in 2016:

  1. Congress can challenge the Clean Power Plan and GHG standards for new power plants under the Congressional Review Act (CRA), but has only 60 working daysa fairly short window to do so after the regulation is published in the Federal Registrar (which happened on October 23, 2015). Yesterday, the Senate narrowly passed CRAs for both power plant rules (52 to 46), and the House is likely to do the same sometime in the near future. However, actually blocking the rule is subject to presidential veto -- something President Obama has made clear he will do and which Congress is unlikely to override since it would require a two-thirds majority vote in both houses of Congress.

  2. While the Clean Power Plan will be subject to legal challenges based on claims that the agency overstepped its authority under the Clean Air Act, EPA has not only the authority, but an obligation to regulate greenhouse gases. Failure to act on GHG emissions by a future U.S. President would likely be challenged in court. For example, the Bush Administration was sued successfully by several states and environmental groups for failing to act to address GHG emissions, with the Supreme Court reaffirming EPA’s obligation three times since 2007.

  3. EPA regulations are required by law to be science-based, and a new administration would need scientific justification to reverse the Clean Power Plan or other existing regulations.

  4. Under the Clean Air Act, EPA has the responsibility to step in with a federal implementation plan to ensure states meet their emissions-reduction mandates set out in the Clean Power Plan. Many of the states challenging the Clean Power Plan in court have already announced they are preparing to comply with it.

  5. Finally, when the next president enters office in 2017, state implementation of the Clean Power Plan will be far along, making it much more difficult to reverse.

Advancing International Climate Action

In addition to these domestic climate actions, the United States has fostered important bilateral climate commitments from China, India, Mexico, Brazil and others. President Obama recently traveled to Alaska to stress the dangers of a warming world, and has used Twitter and other social media platforms to implore Americans and everyone to tackle the climate crisis and reach a strong agreement in Paris. For instance, his first Facebook post was about climate change.

Even though the United States has a lot further to go in the long-term to align its goals with climate science and achieve an 80 percent reduction in GHG emissions by mid-century, its recent actions set the groundwork for ramping up domestic action and for securing more ambition globally. Only with strong action from the entire international community will we be able to stem to worst impacts of climate change.