Coral reefs prevent erosion of the land by protecting the shore from waves, storms and currents. They build up land on islands, so many human populations now live on these islands. Coral reefs are a cheap, valuable form of coastal protection. They are less costly than forming an artificial breakwater structure as these have been known to cost more than $12,000,000 to build whereas the conservation of a coral reef is far less costly.
Coral reefs are very valuable structure. A study by Cesar (1996) found that an estimated US$820-1,000,000 per km of the coastline was lost due to an increase in coral destruction that led to a decrease in coastal protection (Moberg, 1999). This shows that the natural form of a coral reef provides a significant and important role in coastline protection.