The update was produced in response to World Heritage Committee Decision 41 COM7 (Krakow/UNESCO, 2017) to make available the most current knowledge regarding the impacts of climate change on World Heritage properties.

This analysis showed that World Heritage properties containing coral reefs have been increasingly exposed to heat stress during recent years. Nearly half (13) of the 29 World Heritage Listed reef properties were exposed to levels of heat stress that cause coral bleaching, on average, more than twice per decade during the 1985- 2013 period.