U.N. Secretary-General António Guterres ratcheted up his warning about climate change and said the world’s thirst for fossil fuels is a “Frankenstein monster” that spares no one, while calling for greater attention to risks posed by artificial intelligence if its ascent goes ungoverned — even as some leaders played up its promise.

Officials and business executives at the annual gathering in Switzerland said the fight against global climate change would continue with or without the United States.