Global warming can mean record heat or record cold. That is why Hansen talks about heat all the time.
First Florida Cold-water Bleaching Event in 30 Years
NOAA and partners from 12 organizations surveyed sites in the Florida Keys to determine the extent of coral bleaching, and death, in the wake of record low-water temperatures. Scientists assessed coral health at more than 78 sites from January 25 to February 12 to determine the severity of coral bleaching and reefs most affected.
During the first two weeks of January 2010, water temperatures in some parts of the Keys dropped into the upper 40s and lower 50s, which is about
20 degrees Fahrenheit lower than the typical temperatures of the upper 60s and lower 70s. The lethal lower limit for corals is 60 degrees Fahrenheit.
According to reef biologists, the influx of cold water from Florida and Biscayne bays appears to be responsible for the coral deaths in nearshore waters of the Florida Keys National Marine Sanctuary. The hardest hit areas were the inshore and mid-channel reefs from Biscayne Bay (southeast Florida) to Summerland Key (island in the Florida Keys). Fortunately, the offshore reefs most frequented by divers and sportfishers were buffered by warmer waters of the Florida Current and spared severe impact.
h/t to Ivan