DAVOS, Switzerland -- President Donald Trump bragged Tuesday about the American economy and rejected warnings that the world is barreling toward an environmental crisis, a key concern at this year's World Economic Forum.
Speaking to the annual economic summit in the Swiss Alps, Trump boasted of producing more "traditional fuels" like natural gas and coal that contribute to global warming.
He urged optimism at a time when many business leaders, politicians and activists here have expressed anxiety about waning international cooperation and climate change, trends that Trump has either championed or dismissed.
"We must reject the perennial prophets of doom and their predictions of the apocalypse," Trump said. "They are the heirs of yesterday's foolish fortune tellers."
Trump said the United States would support a new global effort to plant one trillion new trees, drawing polite applause in the conference hall. But there was no doubt that the president is out of step with the rest of the summit.
Klaus Schwab, a German engineer and economist who founded the World Economic Forum five decades ago, sounded a much more pessimistic tone shortly before Trump spoke.
"The world is in a state of emergency, and the window to act is closing," he said.
Simonetta Sommaruga, the president of Switzerland, expressed alarm about the effects of climate change as global temperatures rise.
"The world is on fire," she said. "We see the rain forest burning in the Amazon and the bush fires burning in Australia."
Sommaruga added, "When economic interests are placed above the functioning of the natural world ... the consequences for human and for the economy are dramatic."