U.N. Secretary-General Antonio Guterres said Sunday that the world’s efforts to stop climate change have been “utterly inadequate" so far and there is a danger global warming could pass the “point of no return.” Speaking before the start Monday of a two-week international climate conference in Madrid, the U.N. chief said the impact of rising temperatures — including more extreme weather — is already being felt around the world, with dramatic consequences for humans and other species.