As his impeachment trial got underway in the Capitol, the president did not take a day off from humiliating the United States. He was in Switzerland attending the Davos World Economic Forum where climate change was near the top of the agenda. Time Person of the Year and Nobel Peace Prize nominee Greta Thunberg kicked things off with her familiar message.

Greta Thunberg brought a stark message to the business elite gathering in Davos: Everybody is talking about climate change, but nobody is doing anything.

Her appearance at the opening of the World Economic Forum was a striking sign that the debate about how to stop the Earth warming has become mainstream in business circles. Yet only a handful of executives from the oil, gas and coal industries that are chiefly responsible for warming the planet were seen attending the panel at which Thunberg spoke on Tuesday.

Trump, however, did not mention climate change directly in his remarks, choosing instead to obliquely characterize the problem as foolish doomsaying.

Trump landed at Davos on Tuesday morning and was welcomed by the words “Act on climate,” carved into the snow on a hill near the helicopter landing zone. He didn’t mention the topic in his speech at the forum later in the day, focusing instead on America’s growing economy and record oil and gas production.

“This is not a time for pessimism, this is a time for optimism,” Trump said as Thunberg watched from the audience. “We must reject the perennial prophets of doom and their predictions of the apocalypse. They are the heirs of yesterday’s foolish fortune tellers.”

It seems fitting that he’d act like an idiot and a pariah on the international stage even as the U.S. Senate tries to determine if he should be removed from office for abusing his power and contempt of Congress.