Since 1872, there has been a dramatic increase in the global number and extent of nationally designated protected areas (Figure 2).
The World Database on Protected Areas (WDPA) records all nationally designated terrestrial and marine protected areas whose extent is known. These data are collected from national and regional governing bodies and non-governmental organizations. Currently, there are over 120,000 protected areas (2008 estimate, UNEP-WCMC), covering about 21 million square kilometers of land and sea. Since 1872, there has been a dramatic increase in the global number and extent of nationally designated protected areas (Figure 2). Well-planned and -managed protected areas not only benefit species at risk, but other species associated with them, thereby increasing the overall amount of biodiversity conserved. Despite increases in the size and number of protected areas, however, the overall area constitutes a small percentage of the earth's surface. Because these areas are critical to the conservation of biodiversity, the designation of more areas for protection and increases in the sizes of those areas already in existence are necessary.