Huge swathes of the coral at Rangiroa in French Polynesia died during three months of exceptionally warm weather in 1998, when sea temperatures soared to an average of 32 degrees centigrade for the first time.
Research by Newcastle University's Department of Marine Sciences has shown damage to the 800-year old coral reefs was catastrophic, and that it would take more than 100 years to return to its former glory.
Dr Peter Mumby, Royal Society Research Fellow at the University said: "Usually when sea temperatures rise, the coral usually withers slightly but is able to recover.
"But in 1998 global warming caused the sea temperatures to soar to incredibly high levels and in some areas of the ocean there were sustained temperatures of 33-34 degrees centigrade - in previous years temperatures averaged at 28 degrees.
"This caused the corals to die, and damage like this can only be rectified over the long term - we think about 100 years."
Divers from all over the world enjoy the spectacular natural environment at Rangiroa. As well as the coral reefs, it has one of the most wide ranging selection of wildlife in the world - whales, dolphins, turtles and manta rays. The lagoon is also a pearl farming area and a mecca for hundreds of wealthy tourists each year.
Marine Biology