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What percent of the earth is land and how much is water?

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smallys-army | Student, Undergraduate | eNoter

Posted November 10, 2008 at 8:04 PM via web

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What percent of the earth is land and how much is water?

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Kay Morse | College Teacher | (Level 1) Senior Educator

Posted January 25, 2014 at 12:39 AM (Answer #5)

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There are generally two versions of the answer to this question. The first is the more general about 70% of Earth is water while about 30% is land (US Geological Society). The second is the more specific 71% of Earth is water while 29% is land. Both will serve, depending upon your need and aim. The interesting thing is that the percentage of water on Earth does not include only the obvious sources of water, like oceans and lakes, but less obvious sources as well.

The totality of Earth's water is comprised of water in the oceans, water in the air, water in frozen icecaps and glaciers, water in underground aquifers, and water in lakes, rivers and ponds. The largest portion of all this water is found in oceans and seas--being saline water--which hold between 96.5% and 97.5% of all water. That leaves between 3.5% and 2.5% distributed between all Earth's freshwater sources, including water vapor in the air and water in occupants of Earth (US Geological Society). Earth's hydrologic cycle, the movement of water from Earth to air to Earth's occupants, keeps the water circulating and going through various hydrologic phases, liquid, vapor and frozen forms such as snow and ice.

If the water above ground, saline and freshwater, on Earth is measured by volume, the total volume would cover about 1,064 miles in diameter and more than 335,000,000 cubic miles. The third greatest source of water, after (1) oceans and seas and (2) icecaps and glaciers, is ground water, or aquifers. The volume of aquifer water is about 5,614,000 cubic miles. Compare this to the second greatest (icecaps, glaciers) at about 5,773,000 cubic miles. These volumes are surprisingly close while saline oceanic water bears no comparison at all, with a volume of 321,000,000 cubic miles. About 30%, then, of Earth's total freshwater is ground aquifer water or about one-third the amount frozen is icecaps and glaciers. Rivers constitute the smallest volume of Earth's water--aside from biological water in Earth's occupants--with a volume of 509 cubic miles. 

It is interesting to note that of Earth's freshwater sources, about 69% is in icecaps and glaciers (NOAA). This establishes a significant link between ocean levels and ice sheets as they calf, break off, or in other ways melt in mountain glaciers, Antarctica, Greenland and other significant ice zones. Since oceans cover so significant an expanse of Earth's surface, it is not surprising that they play a significant role in global climate stability and in global climate change. Because of the oceans' importance, more and more studies are revealing more and more interactions and connections. For instance, while warming temperatures from greenhouse gases cause greater ocean cloud cover, counteracting some of the rise in Earth temperature, the warming is also raising sea levels and making ocean waters more acidic affecting saltwater flora and sea creatures. Findings published in Nature in January 2014 show that warming currents in the North Atlantic adversely affect (1) "sea-ice redistribution" (i.e., shifting positions of large bodies of sea-ice) in Antarctica, (2) melting ice in the southern icecap of Antarctica, (3) a warming climate with (4) increased ice melt in Antarctica. Greenland and Antarctica together hold about 99% of Earth's freshwater ice, which is undergoing significant changes in location and water phase (from frozen to liquid and vapor).

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lynn30k | High School Teacher | (Level 3) Associate Educator

Posted November 10, 2008 at 8:32 PM (Answer #1)

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71% of the earth's surface is covered with water; 29% is land. Most of the 71% that is covered in water is oceans.

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dananagoud | Student, Grade 9 | eNoter

Posted August 2, 2012 at 1:16 PM (Answer #2)

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71%of erth's surface is covered by water,29% by land 91% of water in ocean

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gelsaied | Student, College Freshman | Honors

Posted September 17, 2013 at 1:57 AM (Answer #3)

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About 71% of the Earths surface is covered by water;29% of it is land. The oceans hold about 96.5% of all Earths water.

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adarshanurag | Student, Grade 11 | Valedictorian

Posted January 22, 2014 at 4:06 PM (Answer #4)

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About 71% of the Earth's surface is covered by water and 29% of Earth's surface is land.

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Yojana_Thapa | Student, Grade 10 | Valedictorian

Posted January 27, 2014 at 10:46 PM (Answer #6)

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71% is covered with water. 29% is land.

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atyourservice | TA , Grade 10 | Valedictorian

Posted July 29, 2014 at 1:54 AM (Answer #7)

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71% of Earth is water while 29% of it is land

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taangerine | Student, Grade 11 | Valedictorian

Posted July 29, 2014 at 7:14 AM (Answer #8)

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Approximately ` ` 3/4 (71%) of the Earth is water, while approximately 1/4 (29%) of the Earth is land. 

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givingiswinning | Student, Grade 10 | Valedictorian

Posted July 31, 2014 at 11:23 PM (Answer #9)

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 70% of Earth is water and about 30% is land 

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