The Big Threat Has Been Climate Change. Now Comes A.I.

New warnings that humans are flirting with out-of-control artificial intelligence raise an uneasy question: has A.I. surpassed climate change as one of humanity’s gravest risks? Though the danger of the technology is hard to assess, the worst-case scenario—human extinction—makes other earthly concerns seem small. Yes, climate change is creating dangerously hot conditions, fueling superstorms and killing crops, and it may lead to planetary upheaval. But that only matters if our civilization is still recognizable. All of this leaves climate activists competing for a finite pool of political consideration. As diplomats and world leaders gather at the United Nations to grapple with the planet’s most pressing problems, some worry that global warming could be overlooked even as it worsens.