Turks and Caicos Islands

Vulnerability of coral reefs to climate change
Although fragile, coral reefs have shown the ability to acclimatize and adapt to temporal and spatial
changes in their environment throughout their geological history. However, the rate of SLR may exceed the
vertical growth rate of coral and decrease the amount of sunlight available to them thus causing them to
grow even more slowly. Increased atmospheric CO2 is also causing changes in atmospheric and oceanic
characteristics with which corals must contend. Ocean acidification, SLR and increased SST present
additional stresses on coral reefs around TCI that are already threatened with coastal development and
increased pressures from fishing, diving and boating activities.
GCM projections indicate increases in sea-surface temperatures throughout the year. Projected increases
range between +0.9˚C and +2.7˚C by the 2080s across all three emissions scenarios. The range of
projections under any single emissions scenario spans roughly around 1.0 to 1.5˚C (see Section 3). Increases
in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching
events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals (Nicholls,
2007). TCI was spared the worst effects of the 2005 Pan Caribbean bleaching episode. Various coral species
showed bleaching at depths of up to 15m but of 166 coral colonies at The Warhead, The Fishbowl and
Tuckers Reefs, only three colonies (one Montastraea annularis and two Agaricia agaricites) were
completely bleached; 87 colonies showed partial bleaching. By December of the following year colonies
showed signs of recovery with little evidence of coral mortality (Jones, et al., 2008). Increased frequency of
bleaching episodes means reduced recovery time for coral polyps and greater likelihood of mortality.
Furthermore, warmer oceanic waters will facilitate the uptake of anthropogenic CO2, which will change
seawater pH, having a negative impact on coral and other calcifying organisms since more acidic waters will
reduce the availability of aragonite (required for shell/skeleton building) and weaken the skeletal structure
of such organisms.
Other climate related impacts are expected from SLR and extreme events. Rising sea levels may reduce the
amount of available light necessary for the photosynthetic processes of corals and hurricanes can cause
extensive structural damage to coral reefs. The rugosity of a reef helps to break up waves and disperse
wave energy thereby protecting the shoreline from wave impact. However, in so doing coral reefs can be
broken apart and even uprooted from the substrate. It is difficult to predict whether Caribbean corals will
keep pace with SLR, increased SST and other climate change impacts.
What is more certain is that the corals’ ability to adapt to climate change is dependent on the degree of
localized environmental stressors that they are exposed to. The ability of coral reef ecosystems to
withstand the impacts of climate change will depend on the extent of exposure to other anthropogenic
pressures and the frequency of future bleaching events (Donner, 2005). Coral reefs have been shown to
keep pace with rapid postglacial sea-level rise when not subjected to environmental or anthropogenic
stresses (Hallock, 2005). Action must be taken to protect coral reefs from poor water quality, over-fishing
and physical damage from tourism activities as weakened and slow growing reefs are less able to provide
effective protection to shorelines or sediment for beach sand. Poor quality reefs will detract from the diving
and snorkelling experience for which TCI is so well known and potentially result in significant loss of its
competitive advantage in the tourism industry.
Vulnerability of fisheries to climate change
As previously discussed, climate change will have negative impacts on coral cover, seagrass beds and
mangrove ecosystems that are all important to various life stages of commercial fish. A loss or partial loss
of these nursery habitats will therefore reduce the abundance of lobster and conch. Severe fluctuations in
SST and local salinities could also compromise larval development and subsequently fish stocks. Declines in
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