WETLANDS
Humans are believed to have destroyed 50 percent of Earth’s wetlands--in California’s Central Valley the figure is 99 percent--by draining swamps to build farms and houses and by harvesting bogs for peat. Wetlands are havens for many species and are also natural wastewater treatment plants.
EXTINCTIONS
Researchers this past year estimated that extinctions are occurring between 100 and 1,000 times faster now than they did before humans were around. The rate is greatest in hot spots that contain many endemic species. For example, Hawaii once supported 135 species of land birds that were found nowhere else: 101 are already extinct, and another 24 are rare or threatened.
NITROGEN POISONING
