Coral reefs are geologically ancient ecosystems that have provided excellent historical evidence of global climatic changes and some of the best indications extant of ecosystem response to such changes. Yet coral reefs are believed by some to be indicators of global climate change in more than just the historical sense. There has been considerable recent speculation in the press, discussion among reef researchers, and testimony on the topic of coral "bleaching," a phenomenon that some interpret as a stress reaction of reef corals to elevated sea surface temperature (SST's) caused by global climate change. This interpretation has been met with considerable skepticism from many in the scientific community, yet it has nonetheless captured considerable attention in the press and in Congress. Coral bleaching is a possible present indicator of climate change. This workshop will meet a critical need to assess the state of our knowledge about coral bleaching and, in the larger sense, to determine research needs for the next decade for understanding the effects of potential global climate change on shallow water tropical marine ecosystems such as coral reefs.