The water off South Florida is over 90 degrees Fahrenheit (32 Celsius) in mid-July, and scientists are already seeing signs of coral bleaching off Central and South America. Particularly concerning is how early in the summer we are seeing these high ocean temperatures. If the extreme heat persists, it could have dire consequences for coral reefs.
A paper by NOAA scientist Derek Manzello showed that in the Florida Keys, the number of days per year in which water temperatures were higher than 90˚F (32˚C) had increased by more than 2,500% in the two decades following the mid-1990s relative to the prior 20 years.
A recent paper by John Morris, a scientist in my lab in Florida, shows that around 70% of reefs are now net erosional in the Florida Keys, meaning they are losing more habitat than they build.