Covering nearly one-third of the Earth's surface, the Pacific Ocean is largely water yet also contains myriads of islands (Figure 12.1): a few larger ones like Hokkaido (Japan) and New Caledonia, and a host of smaller ones. Most smaller islands are arranged in clusters, many classified as archipelagic (such as Fiji and the Galapagos), others within groups that are more linear (like the Hawaiian Islands and most in French Polynesia). Only a few islands are truly isolated (like Nauru and Niue). Most islands are located in the southwest quadrant of the Pacific and in lower latitudes, where the processes by which islands originate and endure are most active (Nunn, 1994). Owing to this concentration, most smaller islands have tropical climates and, largely on account of their comparative smallness and remoteness, most such islands are also considered part of the 'developing world'. Islands are innately more vulnerable to many of the most powerful forces of environmental changes because of their insularity. Islands have larger coastal length to land area ratios than continents. On account of their shapes, many smaller Pacific Islands have some of the highest such ratios of any of the world's landmasses (Table 12.1).