Map references:
Physical Map of the World, Political Map of the World, Standard Time Zones of the World
Area:
total: 510.072 million sq km
land: 148.94 million sq km
water: 361.132 million sq km
note: 70.8% of the world's surface is water, 29.2% is land
Area - comparative:
land area about 16 times the size of the US
Land boundaries:
the land boundaries in the world total 250,708 km (not counting shared boundaries twice); two nations, China and Russia, each border 14 other countries
note: 44 nations and other areas are landlocked, these include: Afghanistan, Andorra, Armenia, Austria, Azerbaijan, Belarus, Bhutan, Bolivia, Botswana, Burkina Faso, Burundi, Central African Republic, Chad, Czech Republic, Ethiopia, Holy See (Vatican City), Hungary, Kazakhstan, Kyrgyzstan, Laos, Lesotho, Liechtenstein, Luxembourg, Macedonia, Malawi, Mali, Moldova, Mongolia, Nepal, Niger, Paraguay, Rwanda, San Marino, Serbia, Slovakia, Swaziland, Switzerland, Tajikistan, Turkmenistan, Uganda, Uzbekistan, West Bank, Zambia, Zimbabwe; two of these, Liechtenstein and Uzbekistan, are doubly landlocked
Coastline:
356,000 km
note: 94 nations and other entities are islands that border no other countries, they include: American Samoa, Anguilla, Antigua and Barbuda, Aruba, Ashmore and Cartier Islands, The Bahamas, Bahrain, Baker Island, Barbados, Bermuda, Bouvet Island, British Indian Ocean Territory, British Virgin Islands, Cape Verde, Cayman Islands, Christmas Island, Clipperton Island, Cocos (Keeling) Islands, Comoros, Cook Islands, Coral Sea Islands, Cuba, Cyprus, Dominica, Falkland Islands (Islas Malvinas), Faroe Islands, Fiji, French Polynesia, French Southern and Antarctic Lands, Greenland, Grenada, Guam, Guernsey, Heard Island and McDonald Islands, Howland Island, Iceland, Isle of Man, Jamaica, Jan Mayen, Japan, Jarvis Island, Jersey, Johnston Atoll, Kingman Reef, Kiribati, Madagascar, Maldives, Malta, Marshall Islands, Martinique, Mauritius, Mayotte, Federated States of Micronesia, Midway Islands, Montserrat, Nauru, Navassa Island, New Caledonia, New Zealand, Niue, Norfolk Island, Northern Mariana Islands, Palau, Palmyra Atoll, Paracel Islands, Philippines, Pitcairn Islands, Puerto Rico, Reunion, Saint Barthelemy, Saint Helena, Saint Kitts and Nevis, Saint Lucia, Saint Pierre and Miquelon, Saint Vincent and the Grenadines, Samoa, Sao Tome and Principe, Seychelles, Singapore, Solomon Islands, South Georgia and the South Sandwich Islands, Spratly Islands, Sri Lanka, Svalbard, Tokelau, Tonga, Trinidad and Tobago, Turks and Caicos Islands, Tuvalu, Vanuatu, Virgin Islands, Wake Island, Wallis and Futuna, Taiwan
Maritime claims:
a variety of situations exist, but in general, most countries make the following claims measured from the mean low-tide baseline as described in the 1982 UN Convention on the Law of the Sea: territorial sea - 12 nm, contiguous zone - 24 nm, and exclusive economic zone - 200 nm; additional zones provide for exploitation of continental shelf resources and an exclusive fishing zone; boundary situations with neighboring states prevent many countries from extending their fishing or economic zones to a full 200 nm
Climate:
a wide equatorial band of hot and humid tropical climates - bordered north and south by subtropical temperate zones - that separate two large areas of cold and dry polar climates
Terrain:
the greatest ocean depth is the Mariana Trench at 10,924 m in the Pacific Ocean
Elevation extremes:
lowest point: Bentley Subglacial Trench -2,540 m
note: in the oceanic realm, Challenger Deep in the Mariana Trench is the lowest point, lying -10,924 m below the surface of the Pacific Ocean
highest point: Mount Everest 8,850 m
Natural resources:
the rapid depletion of nonrenewable mineral resources, the depletion of forest areas and wetlands, the extinction of animal and plant species, and the deterioration in air and water quality (especially in Eastern Europe, the former USSR, and China) pose serious long-term problems that governments and peoples are only beginning to address
Land use:
arable land: 13.31%
permanent crops: 4.71%
other: 81.98% (2005)
Irrigated land:
2,770,980 sq km (2003)
Natural hazards:
large areas subject to severe weather (tropical cyclones), natural disasters (earthquakes, landslides, tsunamis, volcanic eruptions)
Environment - current issues:
large areas subject to overpopulation, industrial disasters, pollution (air, water, acid rain, toxic substances), loss of vegetation (overgrazing, deforestation, desertification), loss of wildlife, soil degradation, soil depletion, erosion; global warming becoming a greater concern
Geography - note:
the world is now thought to be about 4.55 billion years old, just about one-third of the 13.7-billion-year age estimated for the universe