Right now, Chennai—India’s fourth-largest city with a metro area the size of Chicago—is paralyzed. Flooding from record rainfall—the heaviest in more than a hundred years—has cut off more than 3 million people from basic services for days. At least 270 people have died, and what’s happening should provide a cautionary tale to the world: Chennai is a new type of “natural” disaster, a preview of the Anthropocene, the idea that humans have become a geological-scale force of nature.

November was Chennai’s rainiest calendar month in history: An unimaginable 47 inches fell. Then, this week, things got worse. Wednesday’s rains brought an additional 11 inches—34 times the normal amount. More rain is expected in the coming days, linked to an enhanced northeast monsoon boosted by a record-strong El Niño in the Pacific Ocean and the record-warm Indian Ocean.