#Status of Coral Reefs 2002 - International Coral Reef Action Network

Status of Coral Reefs of the World: 2002
SCIENTIFIC CONCENSUS INCLUDES GLOBAL
WARMING AS A MAJOR THREAT TO CORAL REEFS
A group of 15 world-leading researchers from Australia, Europe and USA met in
Townsville in October 2002, to assess threats to coral reefs and a prognosis for the
future. There was expertise in ecology, geology, palaeontology, oceanography,
climatology and economics. They listed the threats to coral reefs worldwide as: 1.
over-fishing; 2. pollution; and 3. climate change. There is reasonable understanding of
the problems and solutions for 1 and 2; however, the damaging effects of climate
change on coral reefs are not well understood. This presents scientists and managers
with a huge intellectual challenge to integrate scientific knowledge and expertise from
many disciplines to offer effective management solutions to deal with this threat. The
experts concluded that: coral reefs will no doubt change with global warming; an
ecosystem perspective must be used to manage coral reefs with an aim to re-build
ecosystems that are more resilient to stress; and international, national and interagency
collaboration with management efforts is essential.
The ‘resilience’ of a reef to withstand ‘natural’ stress from cyclones or bleaching, has
decreased over the past 200 years under the negative impacts of overfishing and
pollution. If these trends continue, coral reefs will decline further leading to
accelerating losses of biodiversity and economic value. It is necessary to re-build the
resilience of reefs in the face of increasing global climate change and the accompanying
oceanic warming. This can be achieved by better protecting the food webs and key
groups, such as, the herbivores that control algal blooms. In addition, projected
increases in carbon dioxide over the next 50 years exceed the conditions experienced
by coral reefs for more than half a million years. It is apparent that changes are already
underway and some corals are more susceptible than others. This suggests that there
will be changes to coral reef community structure in the future. Ocean chemistry is
also changing due to higher atmospheric carbon dioxide, which may cause dissolution
or weakening of coral skeletons. Emissions of carbon dioxide must be reduced to
avoid this threat. Recent modelling indicates that to achieve the goal of re-building
coral reef resilience and to have some insurance against losses due to changes in ocean
chemistry, 30-50% of reefs should be set aside as MPAs.
The forum urged national leaders and international bodies to make a long-term
commitment to conserve tropical marine ecosystems. They suggested that Australia, as
the only developed country with significant coral reefs, has an obligation to lead this
effort, and should lead the world’s efforts to quickly reduce greenhouse gas emissions.
Full text on www.seaweb.org/pdf/jcu_release.pdf Contact: Terry Hughes James Cook
University, Townsville, Australia terry.hughes@jcu.edu.au
44