Didn't Trump attend Davos?
Found it. Sounds like he said it to their face.
At Davos, Trump urges the world to ignore the 'prophets of doom'
https://www.weforum.org/agenda/2020/01/trump-davos-apocalypse-greta-climate/
In a speech just minutes before teenage activist Greta Thunberg addressed a session called Averting a Climate Apocalypse, Trump warned there were forces at work that aimed to "destroy our economy and wreck our country or eradicate our liberty".
"This is not a time for pessimism. This is a time for optimism. To embrace the possibilities of tomorrow, we must reject the perennial profits of doom and their predictions of the apocalypse. They are the heirs of yesterday's foolish fortune tellers," he said.
"They want to see us do badly, but we don't let that happen. They predicted an overpopulation crisis in the 1960s, mass starvation in the 70s, and an end of oil in the 1990s. These alarmists always demand the same thing: absolute power to dominate, transform and control every aspect of our lives. We will never let radical socialists destroy our economy, wreck our country or eradicate our liberty."