Clinton vows to meet Paris climate pledge, but it won't be easy
© Greg Nash

In her acceptance speech Thursday, Democratic presidential nominee Hillary ClintonHillary Diane Rodham ClintonSanders, Warren meet ahead of potential 2020 bids Hillicon Valley — Presented by AT&T — New momentum for privacy legislation | YouTube purges spam videos | Apple plans B Austin campus | Iranian hackers targeted Treasury officials | FEC to let lawmakers use campaign funds for cyber Comey’s remarks about Trump dossier are not credible, says former FBI official MORE vowed to uphold the U.S. commitment to climate actions under last year's Paris agreement.

"I am proud we shaped a global climate agreement," she said. "Now we have to hold every country accountable to their commitments, including ourselves."

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Clinton's vow drew an implicit contrast with Republican nominee Donald TrumpDonald John TrumpProsecutors investigating Trump inaugural fund, pro-Trump super PAC for possible illegal foreign donations: NY Times George Conway: Why take Trump's word over prosecutors' if he 'lies about virtually everything' Federal judge says lawsuit over Trump travel ban waivers will proceed MORE, who would renegotiate the agreement "because other countries don't adhere to it, and China doesn't adhere to it." In fact, China is on track to meet its Paris pledge ahead of schedule, as I explained in a recent column.

What would it take for the United States to attain our own commitment?

Under the Paris agreement, each nation determined its own contribution to curtailing climate warming emissions. The U.S. pledged to reduce emissions "by 26-28 percent below its 2005 level in 2025."

The EPA's most recent inventory shows net emissions were already down 8.6 percent by 2014. That leaves substantial further progress to be made over the next decade.

The Obama administration outlined five actions to help reach the target. First, the Clean Power Plan was expected to reduce to reduce emissions from power plants. That plan was halted by the Supreme Court in February, and now awaits judicial review.

Power plant emissions are already falling rapidly, thanks in part to cheap natural gas and a mild winter. However, if those conditions change and the plan is overturned, emissions could far exceed the levels Obama's plan had hoped for.

The second action is tightening fuel economy standards for heavy-duty vehicles. The Obama administration issued proposed rules in June 2015, though they remain to be finalized.

Third, the U.S. pledged to curb emissions of methane, a potent greenhouse gas. That pledge took shape in March when the U.S. and Canada jointly agreed to cut oil and gas sector methane by 40 to 45 percent by 2025. That would bring total greenhouse gas emissions 1.4 percentage points closer to the overall target. Targeting landfill methane could yield additional progress.

The U.S. also plans to curtail hydrofluorocarbons (HFCs). These refrigerants can be thousands of times as potent as carbon dioxide, and represent 2.5 percent of the overall inventory. Recent talks in Vienna worked toward developing a global plan for HFCs.

Finally, the U.S. pledged to reduce emissions from buildings and government operations. The impact of those efforts remains unclear.

Taken together, Obama's five steps represent an ambitious undertaking. Even so, they would likely leave the U.S. well short of its 26 percent reduction target.

The Energy Information Administration forecasts energy sector carbon dioxide emissions will fall 5.9 percent from 2014 to 2025. That's for a case that assumes the Clean Power Plan proceeds and heavy-duty vehicle standards are finalized. Factoring in the progress before 2014 and the methane and HFC controls noted above, we would need roughly 8 percentage points of further cuts to meet our Paris pledge.

That gap could be closed in a number of ways. For example, the World Resources Institute (WRI) issued a 10-point plan demonstrating how the U.S. could attain its Paris pledge. Their plan includes, but extends beyond, the actions described above. It would strengthen the Clean Power Plan; enhance energy efficiency across the residential, commercial and industrial sectors; set emissions standards for aircraft; tighten fuel economy standards for cars; reduce travel demand; and enhance uptake of carbon by vegetation.

The WRI crafted the steps to be achievable under existing laws, without requiring legislative action. Their economic modeling claims the plan would have minimal impact on the economy and jobs. Still, the feasibility for a new administration to implement such an ambitious plan remains to be seen.

The Clinton campaign has outlined its own climate plan, including tougher efficiency standards, a $60 billion Clean Energy Challenge and investments in energy infrastructure. The impact of the plan is difficult to quantify, despite its pledge to achieve up to 30 percent emission reductions from 2005 levels by 2025.

Holding ourselves accountable to our Paris commitment will be an ambitious undertaking. However, maintaining that commitment will bolster U.S. credibility in holding other countries accountable as well.

That credibility will be especially crucial when negotiators from around the world meet in Morocco to advance the Paris agreement. Ironically, those talks convene this November, the week of the U.S. election.

Cohan is an associate professor in the Department of Civil and Environmental Engineering at Rice University.


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