Irrigated land: 214,000 sq km (1998 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-Marine Living Resources, Antarctic Seals, Antarctic Treaty,
Climate Change, Desertification, 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, Hazardous Wastes
Geography - note: world's third-largest country by size (after Russia and Canada) and by population (after China and India); Mt. McKinley is highest point in North America and Death Valley the lowest point on the continent
People United States
Population: 280,562,489 (July 2002 est.)
Age structure: 0-14 years: 21% (male 30,116,782; female 28,765,183) 15-64 years: 66.4% (male 92,391,120; female 93,986,468) 65 years and over: 12.6% (male 14,748,522; female 20,554,414) (2002 est.)
Population growth rate: 0.89% (2002 est.)
Birth rate: 14.1 births/1,000 population (2002 est.)