The local variations in impact expected to result from global climate change, and the complex ways in which coral reefs and human societies interact mean that there is no single way to manage reef resources for their conservation -- and a narrow scientific approach to management is likely to prove inadequate.

Policy-makers, environmental managers and scientists will need information on local and regional trends in demographic, economic and environmental conditions to provide not only management information but the background against which climate change and sea-level rise impacts on reef systems can be evaluated. As global and regional models of climate improve, assessments will need to be reviewed and updated at regular intervals. We have to monitor the health of coral reefs and their communities more systematically than before.

Managers and planners must also start to listen to indigenous people who have been taking good care of their natural resources for centuries. Many Pacific Island cultures, for example, developed traditional conservation and management systems that controlled over-exploitation. Free access to marine resources was generally not the rule in these island communities. Long before biologists and economists trained in the industrialised world promoted the idea, these peoples operated "limited entry" rules that conserved fishery stocks on small coral reefs.

A system of resource management that makes full use of the knowledge and expertise of local communities is vital if we are to develop integrated coastal zone management that is effective in a changing world.

A narrow scientific approach to management is likely to prove inadequate.

Since the mid-1980s, corals in the Caribbean region and elsewhere have suffered a series of bleaching events. In extreme cases the corals have died. Bleaching has been linked by some scientists to abnormally high seawater temperatures or prolonged peak seawater temperatures in summer. Other scientists argue that the satellite measurement of seawater temperature is not a true reflection of the actual temperature of the water surrounding the reef and thus that the evidence for temperature causing these events is not conclusive.

The crown-of-thorns-starfish, which caused serious damage in the Great Barrier Reef of Australia two decades ago, has been blamed for die-off of corals in large numbers in Sri Lanka, Mauritius, Malaysia and Indonesia. Are these natural fluctuations or are they caused by human activities?

Again the scientists are divided in their opinion concerning the cause of these outbreaks. Some believe that these reflect natural population changes, others that they result from human interference and in particular increased loads of nutrients to reef systems. More information from co-ordinated global research and monitoring is required to resolve these uncertainties.