The closest Mr. Trump’s speech at Davos came to environmental issues was his claim that the United States had the cleanest air and drinking water on Earth. In fact, the Trump administration has pushed through a plan to weaken clean-water regulations. And air pollution in the United States has worsened since 2016, reversing decades of improvements, according to researchers at Carnegie Mellon University.

Mr. Trump dismissed the activists as advocating a form of “radical socialism” that Americans would reject. While he got only perfunctory applause, his message resonated with some in the business-heavy audience.

Critics pointed to a contradiction that they said the corporate world had been unable to resolve: how to assuage the appetite for economic growth, based on gross domestic product, with the urgent need to check carbon emissions.

“It’s truly a contradiction,” said Johan Rockström, director of the Potsdam Institute for Climate Impact Research. “It’s difficult to see if the current G.D.P.-based model of economic growth can go hand-in-hand with rapid cutting of emissions,” he said.

Ms. Thunberg, for her part, largely repeated the warning she issued at the United Nations last year and for which she has drawn widespread global attention.

She spent several weeks in the United States, joining school climate strikes, visiting Native American activists at the Standing Rock Sioux reservation, which covers parts of North and South Dakota, and testifying in Congress. There, when asked to submit her remarks, she opted instead to submit a report issued in October by the Intergovernmental Panel on Climate Change spelling out the threats of global temperature rise.

Ms. Thunberg has always maintained that she has no interest in meeting Mr. Trump and suggested that he consult climate scientists if he wants to learn the facts. While the audience warmly greeted her call for action, she, too, was not without her critics.