The existence and causes of coral bleaching are recognized as an increasing world-wide environmental concern related to climate change. A number of experiments have been conducted since the early 1970s at the Hawai’i Institute of Marine Biology’s (HIMB) Coral Reef Ecology Laboratory in Kāne’ohe Bay, Hawai’i and the Mid-Pacific Marine Laboratory (MPL) at Enewetak, Marshall Islands to determine the long-term temperature thresholds inducing coral bleaching. A new study published in PeerJ replicates 1970s experiments and provides encouraging evidence to suggest corals today are adapting at an unexpectedly rapid rate. Still, these rates are being outpaced by rising ocean temperatures.