According to the estimate, about 34 percent of the world's coasts are at high potential risk of degradation, and another 17 percent are at moderate risk. Most of the coastal ecosystems potentially threatened by development are located within northern temperate and northern equatorial zones. The study drew upon digitized map data and defined coastal zones to include the land area within 60 kilometers of the coast and the adjacent nearshore waters.
Population density measures potential threats from coastal development and pollution.
Road density is an indirect measure of access to coastal resources and coastal development. Pipeline density measures the potential threat of oil pollution and of spills of other industrial wastes. Each of the five indicators was given equal weight in the construction of a final index of potential threat to coastal ecosystems. The presence of cities and ports automatically defined those units of the coastal zone as being under a high threat. The analysis also considered threats to currently identified national marine protected areas within 100 kilometers of continents and major islands.