In the Equatorial Pacific, the chances for an ocean-surface-cooling La Nina are on the rise (more on this later). But even with a cool pool of water upwelling in this key climate region, the risk to corals in a record-warm world remains high.

This risk comes despite the fact that by June of 2017, NOAA had officially declared an end to the longest global coral bleaching event on record. The event lasted from 2014 to 2017 and impacted multiple major coral reefs for 2-3 years in a row. According to NOAA, the event affected more reefs than any other previous global coral bleaching event. Meanwhile, some reefs that had never before seen significant bleaching — like northern sections of the Great Barrier Reef — saw severe damage.

(A portrait of the world’s worst global coral bleaching event shows that 70 percent of the world’s corals took a major hit…