What Percentage Of All The Earth's Water Is In A Form That Is Useful To Humans And Land Animals

Overview of the distribution of water on planet Globe

A graphical distribution of the locations of h2o on Earth

Virtually water in World's atmosphere and crust comes from saline seawater, while fresh water accounts for nearly one% of the total. The vast majority of the water on Earth is saline or table salt water, with an average salinity of 35‰ (or 3.5%, roughly equivalent to 34 grams of salts in 1 kg of seawater), though this varies slightly according to the amount of runoff received from surrounding land. In all, water from oceans and marginal seas, saline groundwater and water from saline closed lakes amount to over 97% of the water on World, though no closed lake stores a globally significant amount of water. Saline groundwater is seldom considered except when evaluating water quality in arid regions.

The residual of Earth's water constitutes the planet'due south fresh h2o resource. Typically, fresh water is defined as water with a salinity of less than 1 percent that of the oceans - i.e. below around 0.35‰. H2o with a salinity between this level and ane‰ is typically referred to as marginal water because it is marginal for many uses by humans and animals. The ratio of salt water to fresh water on World is around 50 to i.

The planet'southward fresh water is besides very unevenly distributed. Although in warm periods such as the Mesozoic and Paleogene when there were no glaciers anywhere on the planet all fresh water was institute in rivers and streams, today most fresh water exists in the course of ice, snow, groundwater and soil wet, with only 0.3% in liquid form on the surface. Of the liquid surface fresh water, 87% is contained in lakes, eleven% in swamps, and only two% in rivers. Small quantities of water also be in the temper and in living beings.

Although the total volume of groundwater is known to exist much greater than that of river runoff, a large proportion of this groundwater is saline and should therefore be classified with the saline h2o above. There is also a lot of fossil groundwater in barren regions that has never been renewed for thousands of years; this must not be seen every bit renewable water.

Distribution of saline and fresh water [edit]

The total volume of water on Earth is estimated at 1.386 billion km³ (333 million cubic miles), with 97.5% being common salt water and ii.v% being fresh water. Of the fresh h2o, only 0.3% is in liquid class on the surface.^{[2] [three] [4]}

Because the oceans that cover roughly 71% of the expanse of Earth reflect blue light, Earth appears blue from space, and is often referred to every bit the blue planet and the Pale Bluish Dot. Liquid freshwater like lakes and rivers cover well-nigh one% of Earth'southward surface^[five] and birthday with Earth'southward ice cover, Earth'due south surface is 75% water past surface area.^[6]

Source of water	Volume of water in km³ (cu mi)	% total h2o	% salt water	% fresh water	% liquid surface fresh water
Oceans	1,338,000,000 (321,000,000)	96.5	99.0
Pacific Ocean	669,880,000 (160,710,000)	48.3	49.6
Atlantic Ocean	310,410,900 (74,471,500)	22.iv	23.0
Indian Ocean	264,000,000 (63,000,000)	19.0	19.5
Southern Ocean	71,800,000 (17,200,000)	5.18	five.31
Arctic Bounding main	xviii,750,000 (4,500,000)	one.35	ane.39
Water ice and snow	24,364,000 (v,845,000)	1.76		69.six
Glaciers	24,064,000 (5,773,000)	ane.74		68.7
Antarctic ice sheet	21,600,000 (5,200,000)	1.56		61.7
Greenland ice sheet	2,340,000 (560,000)	0.17		6.68
Arctic islands	83,500 (xx,000)	0.006		0.24
Mount ranges	forty,600 (nine,700)	0.003		0.12
Basis ice and permafrost	300,000 (72,000)	0.022		0.86
Groundwater	23,400,000 (v,600,000)	i.69
Saline groundwater	12,870,000 (3,090,000)	0.93	0.95
Fresh groundwater	10,530,000 (ii,530,000)	0.76		30.1
Soil wet	xvi,500 (four,000)	0.0012		0.047
Lakes	176,400 (42,300)	0.013
Saline lakes	85,400 (20,500)	0.0062	0.0063
Caspian Sea	78,200 (18,800)	0.0056	0.0058
Other saline lakes	7,200 (i,700)	0.00052	0.00053
Fresh water lakes	91,000 (22,000)	0.0066		0.26	87.0
African Great Lakes	30,070 (7,210)	0.0022		0.086	28.eight
Lake Baikal	23,615 (five,666)	0.0017		0.067	22.6
North American Great Lakes	22,115 (v,306)	0.0016		0.063	21.1
Other fresh water lakes	xv,200 (3,600)	0.0011		0.043	14.5
Temper	12,900 (3,100)	0.00093		0.037
Swamps	xi,470 (ii,750)	0.00083		0.033	xi.0
Rivers	2,120 (510)	0.00015		0.0061	2.03
Biological water	1,120 (270)	0.000081		0.0032

"Logarithm" Graph of Source of Water in Cubic Miles

Fresh Water Source (including saline lakes and saline groundwater)

Lakes [edit]

Collectively, Earth'southward lakes concur 199,000 km^three of water.^[7] Nearly lakes are in the loftier northern latitudes, far from homo population centers.^{[8] [9]} The North American Great Lakes, which contain 21% of the world's fresh h2o by book,^{[x] [11] [12]} are an exception. The Slap-up Lakes Basin is home to 33 one thousand thousand people.^[13] The Canadian cities of Toronto, Hamilton, St. Catharines, Niagara, Oshawa, Windsor, Barrie, and Kingston and the U.S. cities of Duluth, Milwaukee, Chicago, Gary, Detroit, Cleveland, Buffalo, and Rochester, are all located on shores of the Great Lakes.

Groundwater [edit]

Fresh groundwater is of bully value, especially in arid countries such as China. Its distribution is broadly similar to that of surface river water, but it is easier to shop in hot and dry climates because groundwater storage are much more shielded from evaporation than are dams. In countries such as Yemen, groundwater from erratic rainfall during the rainy season is the major source of irrigation water.

Because groundwater recharge is much more difficult to accurately measure than surface runoff, groundwater is non mostly used in areas where even fairly limited levels of surface water are available. Even today, estimates of total groundwater recharge vary profoundly for the aforementioned region depending on what source is used, and cases where fossil groundwater is exploited across the recharge charge per unit (including the Ogallala Aquifer^[14]) are very frequent and almost e'er not seriously considered when they were beginning developed.

Distribution of river water [edit]

The total volume of water in rivers is estimated at two,120 km³ (510 cubic miles), or 0.49% of the surface fresh water on Earth.^[2] Rivers and basins are frequently compared not according to their static book, only to their flow of water, or surface run off. The distribution of river runoff across the Earth's surface is very uneven.

Continent or region	River runoff (km³/twelvemonth)	Percentage of world full
Asia (excluding Middle East)	13,300	30.vi
South America	12,000	27.6
North America	7,800	17.9
Oceania	6,500	14.ix
Sub-Saharan Africa	iv,000	9.2
Europe	two,900	6.7
Australia	440	1.0
Middle E and Due north Africa	140	0.three

There can exist huge variations within these regions. For case, as much as a quarter of Australia's limited renewable fresh water supply is found in well-nigh uninhabited Cape York Peninsula.^[fifteen] Also, fifty-fifty in well-watered continents, there are areas that are extremely short of water, such as Texas in North America, whose renewable h2o supply totals just 26 km³/yr in an expanse of 695,622 km², or Southward Africa, with but 44 km³/year in 1,221,037 kmⁱⁱ.^[xv] The areas of greatest concentration of renewable water are:

• The Amazon and Orinoco Basins (a full of half dozen,500 km³/year or 15 percent of global runoff)
• East asia
  • Yangtze Basin - i,000 km³/year
• South and Southeast Asia, with a total of 8,000 km³/twelvemonth or xviii percent of global runoff
  • Ganges Basin - 900 km³/yr
  • Irrawaddy Basin - 500 km³/year
  • Mekong Basin - 450 km³/year
• Canada, with over 10 percent of world's river water and big numbers in lakes
  • Mackenzie River - over 250 km³/year
  • Yukon River - over 150 km³/year
• Siberia
  • Yenisey - over 5% of earth's fresh water in basin - second largest after the Amazon
  • Ob River - over 500 km³/year
  • Lena River - over 450 km³/yr
• New Guinea
  • Fly and Sepik Rivers - total over 300 km³/twelvemonth in merely about 150,000 km² of bowl area.

Surface area, book, and depth of oceans [edit]

Body of Water	Surface area (ten6 kmii)	Volume (tenhalf dozen km3)	Mean Depth (m)
Pacific Ocean	165.two	707.6	4,282
Atlantic Sea	82.4	323.6	3,926
Indian Ocean	73.4	291.0	3,963
All oceans and seas	361	1,370	3,796

The oceanic chaff is young, thin and dumbo, with none of the rocks inside it dating from whatsoever older than the breakup of Pangaea.^{[ commendation needed ]} Because h2o is much denser than whatever gas, this means that water will period into the "depressions" formed as a event of the high density of oceanic chaff (on a planet like Venus, with no water, the depressions appear to form a vast plain in a higher place which ascension plateaux). Since the low density rocks of the continental crust contain large quantities of easily eroded salts of the brine and alkali metal earth metals, salt has, over billions of years, accumulated in the oceans as a result of evaporation returning the fresh h2o to country as pelting and snowfall.^{[ citation needed ]}

Variability of water availability [edit]

Variability of water availability is important both for the functioning of aquatic species and also for the availability of water for homo utilize: water that is only available in a few wet years must not be considered renewable. Because virtually global runoff comes from areas of very depression climatic variability, the full global runoff is generally of low variability.

Indeed, even in most arid zones, there tends to be few bug with variability of runoff considering nearly usable sources of water come up from high mountain regions which provide highly reliable glacier melt as the chief source of water, which also comes in the summer tiptop menses of loftier demand for water. This historically aided the evolution of many of the peachy civilizations of aboriginal history, and even today allows for agriculture in such productive areas every bit the San Joaquin Valley.

However, in Australia and Southern Africa, the story is different. Hither, runoff variability is much higher than in other continental regions of the earth with similar climates.^[16] Typically temperate (Köppen climate classification C) and arid (Köppen climate nomenclature B) climate rivers in Commonwealth of australia and Southern Africa have as much equally three times the coefficient of variation of runoff of those in other continental regions.^[17] The reason for this is that, whereas all other continents have had their soils largely shaped by 4th glaciation and mountain building, soils of Commonwealth of australia and Southern Africa have been largely unaltered since at to the lowest degree the early Cretaceous and mostly since the previous ice age in the Carboniferous. Consequently, bachelor nutrient levels in Australian and Southern African soils tend to be orders of magnitude lower than those of similar climates in other continents, and native flora compensate for this through much higher rooting densities (e.grand. proteoid roots) to absorb minimal phosphorus and other nutrients. Because these roots absorb then much water, runoff in typical Australian and Southern African rivers does not occur until about 300 mm (12 inches) or more of rainfall has occurred. In other continents, runoff will occur after quite light rainfall due to the low rooting densities.

Climate type (Köppen[18])	Mean annual rainfall	Typical runoff ratio for Australia and Southern Africa	Typical runoff ratio for rest of the earth
BWh	250 mm (10 inches)	1 percent (ii.v mm)	ten pct (25 mm)
BSh (on Mediterranean fringe)	350 mm (fourteen inches)	iii percent (12 mm)	20 per centum (80 mm)
Csa	500 mm (xx inches)	5 percent (25 mm)	35 percentage (175 mm)
Caf	900 mm (36 inches)	fifteen pct (150 mm)	45 pct (400 mm)
Cb	1100 mm (43 inches)	25 percentage (275 mm)	70 percent (770 mm)

The consequence of this is that many rivers in Australia and Southern Africa (equally compared to extremely few in other continents) are theoretically impossible to regulate because rates of evaporation from dams hateful a storage sufficiently large to theoretically regulate the river to a given level would actually allow very little draft to be used. Examples of such rivers include those in the Lake Eyre Basin. Even for other Australian rivers, a storage three times as large is needed to provide a third the supply of a comparable climate in southeastern North America or southern People's republic of china. It likewise affects aquatic life, favouring strongly those species able to reproduce rapidly afterward high floods so that some will survive the adjacent drought.

Tropical (Köppen climate classification A) climate rivers in Commonwealth of australia and Southern Africa do not, in contrast, have markedly lower runoff ratios than those of similar climates in other regions of the world. Although soils in tropical Australia and southern Africa are even poorer than those of the barren and temperate parts of these continents, vegetation tin use organic phosphorus or phosphate dissolved in rainwater as a source of the nutrient. In cooler and drier climates these two related sources tend to be about useless, which is why such specialized ways are needed to excerpt the most minimal phosphorus.

In that location are other isolated areas of high runoff variability, though these are basically due to erratic rainfall rather than different hydrology. These include:^[17]

• Southwest asia
• The Brazilian Nordeste
• The Smashing Plains of the United States

Possible h2o reservoirs inside World [edit]

It has been hypothesized that the h2o is present in the Earth's crust, mantle and even the cadre and interacts with the surface ocean through the "whole-Earth h2o cycle". Still, the actual amount of water stored in the Earth'due south interior still remains under debate. An estimated 1.v to 11 times the amount of water in the oceans may be institute hundreds of kilometers deep within the World's interior, although not in liquid course.^{[ citation needed ]}

Water in Earth'due south mantle [edit]

Ringwoodite is the major stage at the Earth's pall between ~520 and ~660 km depth, possibly containing several weight per centum of water in its crystal structure.

The lower mantle of inner earth may agree every bit much as 5 times more than water than all surface water combined (all oceans, all lakes, all rivers).^[19]

The amount of water stored in the Earth's interior may equal or exceed that in all of the surface oceans.^[20] Some researchers proposed the total mantle water budget may amount to tens of ocean masses.^[21] The water in the Earth's mantle is primarily dissolved in nominally anhydrous minerals as hydroxyls (OH).^[22] These OH impurities in rocks and minerals can lubricates tectonic plate, influence rock viscosity and melting processes, and tedious down seismic waves.^[20] The two mantle phases at the transition zone between Earth'due south upper and lower mantle, wadsleyite and ringwoodite, could potentially comprise up to a few weight percentage of water into their crystal construction.^[23] Direct evidence of the presence of h2o in the Earth'southward mantle was plant in 2014 based on a hydrous ringwoodite sample included in a diamond from Juína, Brazil.^[24] Seismic observations advise the presence of water in dehydration cook at the elevation of the lower mantle under the continental US.^[25] Molecular water (H_twoO) is not the primary water-begetting stage(due south) in the mantle, just its high-pressure grade, ice-VII, also has been institute in super-deep diamonds.

See also [edit]

• Deficit irrigation
• Water resource management
• Magmatic water
• Origin of water on Earth

References [edit]

1. ^ USGS - Earth's water distribution
2. ^ ^{a b} Where is Earth's water?, Usa Geological Survey.
3. ^ Eakins, B.Due west. and Thousand.F. Sharman, Volumes of the Earth'due south Oceans from ETOPO1, NOAA National Geophysical Information Center, Boulder, CO, 2010.
4. ^ Water in Crisis: Affiliate 2, Peter H. Gleick, Oxford University Press, 1993.
5. ^ Downing, J. A.; Prairie, Y. T.; Cole, J. J.; Duarte, C. Yard.; Tranvik, Fifty. J.; Striegl, R. G.; McDowell, W. H.; Kortelainen, P.; Caraco, N. F.; Melack, J. One thousand.; Middelburg, J. J. (2006). "The global affluence and size distribution of lakes, ponds, and impoundments". Limnology and Oceanography. Wiley. 51 (5): 2388–2397. doi:10.4319/lo.2006.51.five.2388. ISSN 0024-3590.
6. ^ "Earth Observatory Water Wheel Overview". Precipitation Educational activity. 2010-09-02. Retrieved 2022-01-xvi .
7. ^ Cael, B. B.; Heathcote, A. J.; Seekell, D. A. (2017). "The volume and mean depth of Earth's lakes". Geophysical Enquiry Messages. 44 (1): 209–218. doi:10.1002/2016GL071378. hdl:1912/8822. ISSN 1944-8007.
8. ^ Verpoorter, Charles; Kutser, Tiit; Seekell, David A.; Tranvik, Lars J. (2014). "A global inventory of lakes based on high-resolution satellite imagery". Geophysical Research Letters. 41 (18): 6396–6402. doi:10.1002/2014GL060641. ISSN 1944-8007.
9. ^ "The world by latitudes: A global analysis of man population, development level and environment beyond the due north–south axis over the by half century". Applied Geography. 31 (ii): 495–507. 2011-04-01. doi:10.1016/j.apgeog.2010.10.009. ISSN 0143-6228.
10. ^ "Cracking Lakes – U.S. EPA". Epa.gov. 2006-06-28. Retrieved 2011-02-19 .
11. ^ "LUHNA Affiliate 6: Historical Landcover Changes in the Great Lakes Region". Biology.usgs.gov. 2003-xi-xx. Archived from the original on 2012-01-11. Retrieved 2011-02-xix .
12. ^ Ghassemi, Fereidoun (2007). Inter-basin water transfer. Cambridge, Cambridge University Press. ISBN978-0-521-86969-0.
13. ^ "Archived re-create". Archived from the original on 2015-11-01. Retrieved 2015-10-29 . {{cite web}}: CS1 maint: archived copy as title (link)
14. ^ Reisner, Marc; Cadillac Desert: The American Westward and its Disappearing Water; pp. 438-442. ISBN 0-14-017824-4
15. ^ ^{a b} Brown, J. A. H.; Australia's surface h2o resource. ISBN 978-0-644-02617-8.
16. ^ McMahon, T.A. and Finlayson, B.L.; Global Runoff: Continental Comparisons of Annual Flows and Tiptop Discharges. ISBN 3-923381-27-1.
17. ^ ^{a b} Pare, Murray C.; McMahon, Thomas A. & Finlayson, Brian 50. (2004). "Continental differences in the variability of annual runoff: update and reassessment". Journal of Hydrology. 295 (ane–4): 185–197. Bibcode:2004JHyd..295..185P. doi:10.1016/j.jhydrol.2004.03.004.
18. ^ This section uses a slightly modified version of the Köppen system establish in The Times Atlas of the Globe, seventh edition. ISBN 0-7230-0265-7
19. ^ Harder, Ben. "Inner Earth May Hold More H2o Than the Seas". National Geographic . Retrieved 14 November 2013.
20. ^ ^{a b} Hirschmann, Marc; Kohlstedt, David (2012-03-01). "Water in Earth's drapery". Physics Today. 65 (3): forty. doi:10.1063/PT.3.1476. ISSN 0031-9228.
21. ^ Ohtani, Eiji (2020-12-18). "Hydration and Dehydration in Earth's Interior". Annual Review of Globe and Planetary Sciences. doi:ten.1146/annurev-world-080320-062509. ISSN 0084-6597.
22. ^ Bell, David R.; Rossman, George R. (1992). "H2o in Earth'south Mantle: The Role of Nominally Anhydrous Minerals". Science. 255: 1391–1397. doi:10.1126/science.255.5050.1391.
23. ^ Kohlstedt, D. L.; Keppler, H.; Rubie, D. C. (1996-05-twenty). "Solubility of water in the α, β and γ phases of (Mg,Iron) two SiO 4". Contributions to Mineralogy and Petrology. 123 (4): 345–357. doi:x.1007/s004100050161. ISSN 0010-7999.
24. ^ Pearson, D. G.; Brenker, F. E.; Nestola, F.; McNeill, J.; Nasdala, L.; Hutchison, Chiliad. T.; Matveev, S.; Mather, Thousand.; Silversmit, G.; Schmitz, S.; Vekemans, B. (March 2014). "Hydrous mantle transition zone indicated by ringwoodite included within diamond". Nature. 507 (7491): 221–224. doi:10.1038/nature13080. ISSN 0028-0836.
25. ^ Schmandt, B.; Jacobsen, Southward. D.; Becker, T. W.; Liu, Z.; Dueker, Thousand. G. (2014-06-13). "Dehydration melting at the meridian of the lower mantle". Science. 344 (6189): 1265–1268. doi:ten.1126/scientific discipline.1253358. ISSN 0036-8075.

Source: https://en.wikipedia.org/wiki/Water_distribution_on_Earth

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