Land use: arable land: 19% permanent crops : 0% permanent pastures: 25% forests and woodland: 30% other: 26% (1993 est.)
Irrigated land: 207,000 sq km (1993 est.)
Natural hazards: tsunamis, volcanoes, and earthquake activity around Pacific Basin; hurricanes along the Atlantic coast; tornadoes in the midwest; mud slides in California; forest fires in the west; flooding; permafrost in northern Alaska is a major impediment to development
Environment - current issues: air pollution resulting in acid rain in both the US and Canada; the US is the largest single emitter of carbon dioxide from the burning of fossil fuels; water pollution from runoff of pesticides and fertilizers; very limited natural fresh water resources in much of the western part of the country require careful management; desertification
Environment - international agreements:
party to: Air Pollution, Air Pollution-Nitrogen Oxides, Antarctic
Treaty, Climate Change, Endangered Species, Environmental
Modification, Marine Dumping, Marine Life Conservation, Nuclear Test
Ban, Ozone Layer Protection, Ship Pollution, Tropical Timber 83,
Tropical Timber 94, Wetlands, Whaling
signed, but not ratified: Air Pollution-Volatile Organic Compounds,
Antarctic-Environmental Protocol, Biodiversity, Desertification,
Hazardous Wastes
Geography - note: world's third-largest country (after Russia and
Canada)
@United States:People
Population: 267,954,764 (July 1997 est.)
Age structure: 0-14 years: 22% (male 29,837,393; female 28,450,028) 15-64 years: 65% (male 87,170,245; female 88,400,551) 65 years and over : 13% (male 13,975,746; female 20,120,801) (July 1997 est.)
Population growth rate: 0.89% (1997 est.)