Simon Donner continued his work linking greenhouse gas emissions to the viability of coral reefs. A key step forward was developing a method for double attribution of coral-reef bleaching; that is, isolating the GHG-induced component of coral bleaching. Developed in conjunction with Tom Knutson of GFDL, the approach, combining modeling and observations, was able to identify the likelihood of a human contribution to the 2005 Caribbean bleaching event, and project the probability of bleaching under various warming scenarios for this century.