Momentum Is Building But Paris Delegates Doubt U.S. Resolve

By Vivienne Walt ~ PARIS 

During his 4o-hour stay in Paris, President Obama delivered impassioned pleas for the world’s leaders to cut down on greenhouse gases and stave off disastrous global warming of the planet. As head of the world’s biggest economy, Obama’s voice booms louder than almost any of the 150 Presidents and Prime Ministers who have gathered for the U.N.’s mammoth climate conference, known as COP 21.

Obama has presented himself as being ‘all in’ on the issue. On Monday he and Microsoft founder Bill Gates unveiled a multibillion-dollar initiative on clean energy research, and he told a packed hall of world leaders: “The United States of America not only recognizes our role in creating this problem, we embrace our responsibility to do something about it.”

On Tuesday, at his press conference wrapping up Paris trip, Obama said:

“Climate change is a massive problem. It is a generational problem, it is a problem that by definition is just about the hardest thing for any political system to absorb. Yet for all of that… I actually think we are going to solve this thing.”

But the niggling question in the minds of many negotiators in the conference hall at COP21: Can the U.S. deliver on Obama’s promises?

Secretary of State John Kerry made it clear earlier this month that the Paris agreement would not be “legally binding,” a reference to the possibility that the Paris agreement would be a “treaty,” which would require a two-thirds majority in the Senate.

That prospect is a non-starter in Washington, where the Republican-controlled Senate has vowed to reject any agreement inked in Paris. Yet, as Fortune’s Tory Newmyer points out, the opposition could find their options limited, since Obama long ago predicted this problem, and in some measure headed it off by implementing a sweeping clean energy program through Executive Order. Under the U.N. process of every country submitting their promises on climate, the U.S.—the second-biggest carbon emitter after China—has committed itself to cutting its greenhouse gases 26% to 28% by 2025 from its 2005 levels.

In Paris, however, the lingering sense is that U.S. promises—even with Obama’s passion—are not necessarily trustworthy, in part because anything that is not legally binding might be changed or rolled back by a future President or Congress.

“It is very much about the U.S.’s credibility as a negotiating partner,” says Yvo de Boer, director general of the Global Green Growth Institute in Seoul and the previous head of the U.N.’s climate conference.

“Obama is saying to other countries, ’whatever you promise in Paris I expect you to deliver,’” de Boer told Fortune on Tuesday in Paris. “Then it is perfectly legitimate for others to say, ‘we expect the same of you.’”

De Boer has reason to worry. When the U.N. negotiated the Kyoto Protocol on climate change in 1997, then-Vice President Al Gore flew into the Japanese city to sign the document. But President Bill Clinton never took it to the Senate for ratification. “The U.S. negotiated Kyoto to the wire, and then walked away,” de Boer says. “So it is a matter of once bitten, twice shy.”

Climate activists in Paris say they have been struck by Obama’s passion for the issue—a stark difference from his early days as President.

Obama was “pathetic during his first four years,” says Kumi Naidoo, executive director of the environmental activist group Greenpeace International. “But in the last four years he’s really gotten with the program.”

But “yes, always” was Naidoo’s reply to a question about whether delegates worry that the U.S. might fail to deliver on its climate promises.

American climate experts and former officials, many of whom are in Paris this week, are much more optimistic. Even within the U.S., they sense far stronger support for a global climate deal than ever before. In interviews, several point to a Yale University survey, which found that 71% of Americans believe it is important for the U.S. to sign the climate deal in Paris, including 64% of Republicans.

“Climate change is becoming like a measure of nation’s credibility in its international moral standing,” says Paul Bledsoe, former climate advisor to President Bill Clinton, who now heads a strategic public policy firm in Washington. Since the 1990s, there is a much bigger realization that any climate plan needs to be global, he says, even though the U.S. might still balk at the idea of signing a international legal agreement.

“People realize that if 10% of countries don’t comply, the other 90% suffer equally, because the problem is global,” Bledsoe tells Fortune.

Still, during Obama’s press conference on Tuesday several reporters expressed doubts that the U.S. would ultimately follow through on its commitments. “My expectation is that we will absolutely be able to meet our commitment,” Obama said in answer to one question about his ability to deliver on his Paris promises. Even if a Republican wins the 2016 election, that person will have to take other countries’ climate concerns seriously in order to influence a range of world issues, he said.

“Ninety-nine percent of world leaders think this is really important,” Obama told reporters. “I think the President of the United States is going to need to think this is really important.”

Read this story on FORTUNE Magazine.