Coral Bleaching Events and Sea Surface Temperature Anomaly Hot Spots, 1997 - 1998
| Analytical Overview |
| The SST anomaly data were developed by NOAA based on the satellite-based monitoring of SST. This product highlights SST anomalies which are greater than one degree above the maximum monthly climatological SST. The bleaching events were compiled at UNEP-WCMC based on reports from various sources. While this may be an entirely natural phenomenon, two points are important to consider for climate change. First, background rises in ocean temperatures exacerbate El Niño events. Second, the temperatures that drove this particular change are not significantly larger than those predicted to be occurring regularly in tropical environments in 50 to 100 years. |
Map Projection
Geographic
Map Description
One direct measure of coral stress is the phenomenon of coral bleaching and mortality associated with widespread elevated sea surface temperatures (SSTs) during the last decade (Hoegh-Guldberg 1999). This is frequently associated with warm temperatures and has been widely predicted to increase in the future. Exposure for one month at temperatures 1 or 2 degrees Celsius higher than the mean averages at the warmest time of year is sufficient to cause the corals to bleach. This map shows the distribution of SST anomalies and coral bleaching events, during one of the largest El Niño events of this century, from late 1997 until mid-1998. Although some records of local coral bleaching date back decades, reports of widespread bleaching have been increasing in recent years. The most recent event was not only widespread, but was also more severe in many areas than earlier events. Actual coral death reached 95 percent in some locations. In a few places massive, centuries-old corals have died; in some other places there has now been at least a partial recovery, with loss of only a few corals.
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Citation:
World Resources Institute - PAGE, 2000
Sources:
- NOAA-NESDIS (National Oceanic and Atmospheric Administration, National Environmental Satellite Data and Information Service) and UNEP-WCMC (United Nations Environment Program - World Conservation Monitoring Centre). 1999, Observed Coral Bleaching Events: 1997-1998.
- Hendee, J.. 1999, Coral-list listserver coral bleaching archives.
Available On-line at: Source Link. - McClannahan, T.. 0, CORDIO data set for the Indian Ocean.
Available On-line at: Source Link. - Wilkinson, C.. 1998. Status of the Coral Reefs of the World.