“No nation will do well if it sits on the sidelines, choking on the fumes generated by obsolete technologies, and failing to share in the benefits of the clean-tech explosion,” Kerry said during a speech at the Massachusetts Institute of Technology’s Sloan School of Management.

Scolding doubters of man-made climate change and warning of global catastrophe if sufficient steps to curb it aren’t taken, Kerry held out renewable energy sources as not just environmentally responsible, but financially lucrative.

CAMBRIDGE — Secretary of State John F. Kerry warned Monday that the country risks disastrous environmental and economic consequences if Donald J. Trump’s administration does not hasten the transition from fossil fuels to renewable-energy sources.


President-elect Trump has questioned what an overwhelming majority of scientists agree on: that climate change is a fact, and fueled by human activity.

“I’m still open-minded,” he said on Fox News last month. “Nobody really knows. Look, I’m somebody that gets it, and nobody really knows. It’s not something that’s so hard and fast.”

Trump’s choice to replace Kerry is former Exxon Mobil chief executive Rex Tillerson, whose confirmation hearing before the Senate Foreign Relations Committee begins Wednesday. Tillerson is expected to face questions about his former company’s environmental record, including allegations it misled the public about climate-change research.

“I’m not going to speculate about the policies that our president-elect and his secretary of state will choose to pursue,” Kerry said, “but I will tell you this: In the time I’ve spent in public life, one of the things I’ve learned is that some issues look a lot different when you’re actually in office, compared to when you’re on the campaign trail.”

Less than two weeks before leaving office, and in what were likely his final remarks in his home state as the nation’s top diplomat, Kerry offered dramatic warnings about the effects of climate change. The 2004 Democratic presidential nominee and former US senator said air samples from Antarctica, purportedly the world’s cleanest atmosphere, already contain 14 percent more carbon dioxide than what scientists have long called the “tipping point.”


“If we don’t go far enough fast enough, the damage we inflict could take centuries to undo — if it can be undone at all. We don’t get a second chance on this one,” Kerry said.

Pointing to recent global-temperature records set at a brisk pace, rapidly melting glaciers, sea levels rising at three times the 20th-century rate, and intensified storms, Kerry said, “Unless we take the steps necessary to change the course that our planet is on, the impacts that we have already seen will pale in comparison to what we will witness in years to come.”

Without mentioning Trump by name, Kerry offered clear warnings for the next administration, predicting that other countries were already eager to tap into a lucrative clean-energy boom.

“If we don’t do it, I’m telling you, the rest of the world is going to go there,” Kerry said.

He also encouraged the development of additional nuclear energy sources, arguing that the peril posed by climate change and advances in nuclear technology made it worth the downsides.

“Go for it,” Kerry said, noting that early in his career he was opposed to nuclear power.

A Trump spokesman did not respond to voice mails requesting comment.

Kerry offered no specifics about his post-State Department plans, but had said before that he intends to return to Boston and work in the private sector. With 11 days remaining until Trump’s inauguration, Kerry joked Monday that he was “about to become one of the most visibly unemployed people in America.”


In an e-mail, Colin Reed, executive director of the Republican opposition group America Rising PAC, said: “John Kerry has earned a reputation for flip flopping, but he’s remarkably consistent when it comes to being out-of-touch. Case in point: making light of being unemployed with a net worth near $100 million.”

Boston Mayor Martin J. Walsh attended Kerry’s speech. The city will host a major climate-change summit with urban leaders from both the United States and China later this year, Kerry announced in China last June.

Jim O’Sullivan can be reached at jim.osullivan@globe.com. Follow him on Twitter at @JOSreports.