Monday, March 12, 2007

Climate change and Caribbean coral reefs

Our latest research on climate change and coral reefs in the Caribbean was published (online) today in the Proceedings of the National Academy of Sciences.

In the study, my colleagues and I used historical temperature data and climate models developed to examine the probability of the widespread coral bleaching happening in the Caribbean, like in 2005, with and without human influence on the climate. For a short summary of our findings, take a look at the department's press release.

The abstract:

Episodes of mass coral bleaching around the world in recent decades have been attributed to periods of anomalously warm ocean temperatures. In 2005, the sea surface temperature (SST) anomaly in the tropical North Atlantic that may have contributed to the strong hurricane season caused widespread coral bleaching in the Eastern Caribbean. Here, we use two global climate models to evaluate the contribution of natural climate variability and anthropogenic forcing to the thermal stress that caused the 2005 coral bleaching event.

Historical temperature data and simulations for the 1870-2000 period show that the observed warming in the region is unlikely to be due to unforced climate variability alone. Simulation of background climate variability suggests that anthropogenic warming may have increased the probability of occurrence of significant thermal stress events for corals in this region by an order of magnitude. Under scenarios of future greenhouse gas emissions, mass coral bleaching in the Eastern Caribbean may become a biannual event in 20-30 years. However, if corals and their symbionts can adapt by 1-1.5°C, such mass bleaching events may not begin to recur at potentially harmful intervals until the latter half of the century. The delay could enable more time to alter the path of greenhouse gas emissions, although long-term "committed warming" even after stabilization of atmospheric CO2 levels may still represent an additional long-term threat to corals.

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