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 and Gulf of Mexico
coasts; tornadoes in the midwest and southeast; mud slides in
California; forest fires in the west; flooding; permafrost in northern
Alaska, 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-Environmental Protocol, 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-Persistent Organic Pollutants,
Air Pollution-Volatile Organic Compounds, Biodiversity, Climate
Change-Kyoto Protocol, Desertification, Hazardous Wastes
Geography - note: world's third-largest country (after Russia and
Canada)
@United States:People
Population: 275,562,673 (July 2000 est.)
Age structure: 0-14 years: 21.25% (male 29,956,875; female 28,597,880) 15-64 years: 66.11% (male 90,345,154; female 91,827,471) 65 years and over: 12.64% (male 14,472,865; female 20,362,428) (2000 est.)
Population growth rate: 0.91% (2000 est.)