Spatial and temporal patterns of mass bleaching of corals in the Anthropocene

TLDR

Coral bleaching, triggered by stressful conditions that expel the algal partner, was once rare enough to allow reef recovery, but warming events such as El Niño are now hotter and more frequent. Across 100 reefs worldwide, the average interval between bleaching events has dropped to less than half its pre‑warming value, leaving insufficient time for full recovery and making future recovery increasingly difficult. Hughes et al., Science, this issue p.

Abstract

Not enough time for recovery Coral bleaching occurs when stressful conditions result in the expulsion of the algal partner from the coral. Before anthropogenic climate warming, such events were relatively rare, allowing for recovery of the reef between events. Hughes et al. looked at 100 reefs globally and found that the average interval between bleaching events is now less than half what it was before. Such narrow recovery windows do not allow for full recovery. Furthermore, warming events such as El Niño are warmer than previously, as are general ocean conditions. Such changes are likely to make it more and more difficult for reefs to recover between stressful events. Science , this issue p. 80