US President Donald Trump has decried climate "prophets of doom" in a speech at the World Economic Forum in Davos, where sustainability is the main theme.
He called for a rejection of "predictions of the apocalypse" and said America would defend its economy.
Mr Trump did not directly name the teenage climate activist Greta Thunberg, who was in the audience.
Later, she excoriated political leaders, saying the world "in case you hadn't noticed, is currently on fire".
Environmental destruction is at the top of the agenda at the annual summit of the world's decision-makers, which takes place at a Swiss ski resort.
I know it's not cool to wish some fckr dead but he is an exception. He's slimy enough to beat impeachment and we will be trading with the orange twunt.