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-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