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United States will miss Paris climate targets without further action, study finds

Although the Obama administration recently announced it will officially sign the climate change agreement forged in Paris nearly a year ago, making good on the deal’s promise to stem greenhouse gases could be a stretch, a new study concludes. 

Even if the United States implements all current and proposed policies, it would miss its 2025 target by as much as 1.5 billion metric tons of carbon dioxide per year—roughly 20% of the nation’s total emissions, according to the analysis published today in Nature Climate Change. The 2025 target is to cut greenhouse gases 26% to 28% below 2005 levels—down to between 4.5 billion and 5.5 billion metric tons.

One big challenge to U.S. efforts to curb greenhouse gas emissions comes this week, as a federal circuit court hears arguments over a challenge to the White House’s major climate change initiative, the U.S. Environmental Protection Agency’s (EPA’s) regulations targeting emissions from power plants. Even if the so-called Clean Power Plan survives the legal gantlet, however, the United States will still fall short in meeting its pledged reductions for 2025 without significant additional efforts, according to researchers at the federal government’s Lawrence Berkeley National Laboratory in Berkeley, California.

The United States could come closer to meeting the 2025 bar if the Clean Power Plan holds up, and U.S. policymakers stack on further measures. Those could include more electricity regulations, and stopping methane leaks from the pipelines and gas drilling. But even then, the United States would reach the goal only in the most optimistic scenario, the authors conclude, and is likely to miss it by half a billion metric tons or more.

Still, the lead author is taking a glass-half-full view of the findings. “I see it as a best level effort, and hopefully with continued movement in the right direction, we’ll be able to get there,” says Jeffery Greenblatt, a greenhouse gas policy analyst in the lab’s Energy Analysis and Environmental Impacts Division. “If the U.S. fell a little short of their goal, I don't think people would roundly criticize them.”

Analysis goes deep

In the run-up to the Paris conference, most of the world’s countries, including the United States, submitted goals they would aim to reach, known as Intended Nationally Determined Contributions, or INDCs. These pledges offer the most detailed account of what countries say they will do to address climate change.

The study is the newest and one of the most comprehensive analyses of the gap between the United States’s Paris promises and real policies. It’s also the first by federal scientists.

The results are in the same ballpark as studies issued earlier by a host of think tanks, with a few important caveats. Closing the gap got a little tougher in the new study thanks largely to recent research showing that emissions of methane—a potent but short-lived greenhouse gas—are higher than previously thought. And the new study makes explicit the potential uncertainty for each policy, showing a range of possible outcomes rather than a single number.

Karl Hausker, a policy analyst at the nonprofit World Resources Institute in Washington, D.C., says the new study shows that although the Barack Obama White House has made progress over 8 years, “there’s more the next president is going to have to do to get there.” But, he says, “this report does not say it's impossible. This report does not say it’s technically infeasible or will destroy the economy.”

Stephen Eule has a less optimistic outlook. The vice president for climate and technology at the U.S. Chamber of Commerce’s Institute for 21st Century Energy in Washington, D.C., says the new study reaffirms that the government will have to dig further for more emissions savings, including into industries such as cement and petrochemicals. “Really the third biggest emissions sector is the industrial sector. No one is talking about regulating the industrial sector. And I think I know why: because it’s a job killer,” Eule says.

Clean Power Plan key

The study underscores the importance of EPA’s Clean Power Plan for meeting the climate change promises. It’s expected to reduce emissions 240 million metric tons in 2025—nearly half the total cuts contained in current or proposed regulations. To help close the remaining gap, Greenblatt and his co-author point to potential reductions from an “enhanced” EPA rule that could add another 407 million metric tons in cuts. But the study offers few details of what the additional regulations would be.

Meanwhile, the fate of the existing power plan remains in doubt. On 27 September, the U.S. Court of Appeals for the District of Columbia Circuit hears arguments in a case challenging the regulations, brought by a coalition of 27 states. The U.S. Supreme Court has put a hold on the EPA rules while the legal fight unfolds.

The new study includes other strategies beyond current policies to help reach the 2025 goal: staunching methane leaks (121 million tons), reducing the use of refrigeration chemicals that are powerful greenhouse gases (67 million tons), and increasing efficiency standards for appliances and buildings (29 million tons each).

Further steps could include pushing for more renewable energy; an aggressive cut in the use of coal and natural gas to make electricity; wider use of electric cars, biofuel, and hydrogen fuel; changes in farming practices; and putting a price on carbon pollution. But the study doesn’t say how much additional cuts would come from each of those actions.

United States still climate leader

Although the U.S. path to meeting its promises is uncertain, it has made further progress than some other countries, says Bill Hare, a climate scientist and CEO of Climate Analytics, a nonprofit climate change consulting firm in Berlin. Hare’s company is part of Climate Action Tracker, a European consortium of private and government groups that analyze the climate change commitments of countries around the world.

Policies in some other countries, including Australia and Canada, threaten to drive them further from their targets, he says. Others, such as India, are expected to see major increases in future emissions. By comparison, Hare says, the U.S. effort, “gets relatively close, within 500 megatons. So that’s not bad.”

All told, the consortium estimates that current policies around the globe translate into a 3.6°C increase in average temperatures by 2100, compared with preindustrial levels, well above the 2°C threshold often noted by scientists, or the 1.5°C goal set out in Paris.

Updated, 9/27/2016, 1:40p.m.: In the last paragraph, the predicted average increase in temperature by 2100 was misstated. It is 3.6°C, with an upper bound of 4.9°C