Thanks in large part to global warming, at least one-third of the coral in the Caribbean, much of it many centuries old and virtually irreplaceable, has died in the last year.

“It’s an unprecedented die-off,” said National Park Service fisheries biologist Jeff Miller, who last week checked 40 stations in the Virgin Islands. “The mortality that we’re seeing now is of the extremely slow-growing reef-building corals. These are corals that are the foundation of the reef … We’re talking colonies that were here when Columbus came by have died in the past three to four months.

Thanks to reader Abby for the wildly depressing tip.