Through negotiating and promoting President Obama's landmark nuclear deal with Iran, Ernest J. Moniz became an unexpected Cabinet star. His Founding Fathers-style coif — flowing gray locks he says were inspired by years in California earning his doctorate at Stanford — also helped make him one of the administration's more recognizable faces.
Now, the 70-year-old Energy secretary has turned toward helping Obama pursue another of his top second-term undertakings: a major international accord on climate change. He is part of the U.S. team at the United Nations climate negotiations underway in Paris.
Moniz, who served as Energy undersecretary in the Clinton administration, came back to the department in 2013 after a job well-suited for his current task: directing MIT's Energy Initiative, where he oversaw research on solar and wind power, battery and storage technologies, as well as energy efficiency technologies like LED, some of which he showed to Obama when the president toured a lab there in 2009.
In Paris, he has focused on the promise of such technology to persuade nations to adopt ambitious targets for reducing carbon emissions.
Based on commitments made by more than 180 nations at the summit, however, the climate agreement expected to emerge by this weekend will fall short of the reductions needed to limit the average global temperature rise to 2 degrees Celsius over preindustrial times. Scientists say that exceeding that target would unleash the worst effects of global warming, including dangerous sea level rise and widespread extinction.
"We want to do a lot better," Moniz said.
In the negotiations, he said, the U.S. has pushed to leave open a path to ramping up targets over time. He also said that the U.S. has emphasized the need for mechanisms to verify that countries are meeting their commitments.
Though Obama hired him three years ago largely because of his clean-energy credentials, Moniz became a key player on nuclear security.
Secretary of State John F. Kerry said that Moniz's expertise in nuclear energy proved crucial in negotiating the deal reached with Iran this year to stop it from developing nuclear weapons.
"We sort of drafted Ernie late as we got into the really technical portions of the negotiation," Kerry recalled recently as he joined Moniz to mark the adoption of the agreement. "He proved to be one of the best draft choices we've ever made."
The two men forged a bond as the talks intensified and they found themselves cooped up together in one European hotel conference room or another.
A 19-day stretch in Vienna was interrupted only for a few hours so Moniz, who has Portuguese roots, could travel to Lisbon to receive the Grand Cross of the Order of Prince Henry the Navigator from Portugal's president.
"I did much better at the negotiation with the Iranians than I did with my State counterparts," he joked of his attempts to take longer breaks away from the talks. "I said, 'Oh, I've only taken enough underwear for eight days. I have to leave.' And then I tried, 'I don't have any more medicine.'"
Kerry has credited Moniz — with a penchant for dark humor and scotch — for helping keep the negotiating team loose. Moniz has an affection for his famous namesake, the Sesame Street character Ernie, and keeps several dolls in his Washington office.
In one particularly tense meeting, an aide recalled, someone strode into the room to place Ernie's companion, Bert, at Moniz's side. "For the tough issues, we call in Bert," Moniz joked in a Twitter message with a photo of the scene.
Obama often leaned on Moniz's nuclear expertise to promote the nuclear deal.
"Our nuclear experts — including one of the best in the world, Secretary of Energy Ernie Moniz — worked tirelessly on the technical details," Obama said in a major speech promoting the accord and challenging the "armchair nuclear scientists."
Moniz also used his political skills. He held dozens of meetings with lawmakers as Congress attempted to kill the deal and earned praise from Democrats and Republicans alike.
Alaska Sen. Lisa Murkowski, the chairwoman of the Senate Energy Committee and a frequent critic of the Obama administration on energy issues, said simply when asked about Moniz: "I love him."
"When he thinks something is doable, he's going to work to get to yes," the Republican senator said. "I think he's a pragmatist. I think he is practical. He's just a genuine article."
Moniz's no-nonsense style was apparent from the start in dealing with climate skeptics.
"I know how to count," he said at a House hearing early in his tenure when a Republican challenged his certainty on the climate science.
"I can count how many CO2 molecules have gone out from fossil fuel combustion," he said, "and I can count how many additional CO2 molecules are in the atmosphere."