Published in GralsWelt 51/2008
Is food becoming scarce?
In April 2008, the government of Tahiti, one of the poorest countries in Central America, was forced to resign after a large demonstration by the population that almost turned into a popular uprising. The reason for these protests were the sharp rise in food prices. One reporter went on to say that these price increases for basic foodstuffs, which have now also caused unrest in other poor countries and will continue to worry, came as a surprise.
“At the beginning of the 1990s, we have to take decisive action to halt population growth, fight poverty and protect the environment. Otherwise we will only leave a poisoned legacy to our children. "
World Population Report 1990 (1, p. 23)
For decades it has been pointed out that with the growing world population the arable land available per capita is decreasing (cf.A devastating footprint“) And it is therefore to be expected that food production will no longer be able to meet demand in the foreseeable future. This problem is exacerbated by the production of fuels from sugar cane, wheat, corn, rice or vegetable oil; all important foods that can be used either for "fuel" or for "bread". Not to mention the madness of cutting down large areas of tropical forests. On the clearing z. B. grow oil palms that provide oil suitable for diesel engines[i].
Is the “blue gold” enough? (8)
In a few years we will be “surprised” by a further shortage in many parts of the world: Water consumption has risen dramatically in the last few decades, and if the demand continues to grow, the most important thing of all food, water, will be lacking!
"Rain Rain, Blessings of heaven!
Bring us cool, clear the dust
And refresh stalks and leaves.
Rain Rain, Blessings of heaven!
Lave my little flowers
that they bloom in the sunshine.
Rain Rain, Blessings of heaven!
Take care of the brook too,
that it can rustle again!
August Heinrich Hoffmann von Fallersleben (1789-1874)
Already in 1980 "Global 2000" warned:
“Freshwater, once an abundant resource in most parts of the world, will become increasingly scarce over the next few decades for two reasons. First, there will be a greater net consumption from cooling towers, but above all from artificial irrigation systems, so that the total stock will decrease. Second, pollution and the effects of hydropower plants will severely limit the use of freshwater - and with it, the supply of freshwater. The deterioration in the situation in the catchment areas of the rivers, not least a result of deforestation, will increase the unpredictability of water supplies, accelerate soil erosion, impair water development projects and reduce the quality of water. It seems inevitable that the function of streams and rivers as habitats for aquatic organisms will increasingly be sacrificed for the purposes of artificial irrigation, human consumption and energy production. This is especially true for the underdeveloped countries. " (2, p. 725).
In 1992/93 the press discovered the subject of "war over water" (1, p. 12; 6). Because vital river systems often flow through several states[ii]who not infrequently fight over the water, even armed conflicts seem preprogrammed. The best known water conflict concerns the Jordan water, which the State of Israel has controlled since the occupation of the Golan Heights in the Six Day War (1967).
The waters of the earth
The earth has an enormous amount of water of 1.38 billion km³. Of these, however, only 2.6 % are fresh water. Most of the fresh water is difficult to access, so we really only have rainwater, a renewable resource, at our disposal. According to "Water for People" (10), the total rainfall on the land area is ~ 110,000 km³ / year. A significant part of it evaporates directly or indirectly through plants. Only the rainwater that rains down directly on fields or commercial forests and the runoff water that flows back into the oceans via rivers or as groundwater can be used in practice.
How much water do people need?
A person needs ~ 2 - 10 liters of drinking water per day to survive. The actual demand for water, including hygiene, is much higher, especially in industrialized countries, where there is the luxury of flushing the toilets with drinking water:
Table 1: Water consumption per person + day excluding agriculture and industry, 2006.
Liters of water land
145 Austria / Denmark
A lot of water is also required for food production. To feed a person with modest demands is required:
Table 2: Minimum water requirement for drinking and nutrition at fleis poor diet:
Requirement per person: 3 m³ / day = 1,095 m³ / year
for 6.5 billion: ~ 7,150 km³ / year
Source: 9, P. 39.
The following data are given for the actual water consumption of mankind:
Table 3: Population in millions and water consumption worldwide in km³ / year, 1977:
Population Energy Irrigation Industry Total + Household Africa 405 11 60.8 16.2 88 Asia 2,290 68 1,400 129 1,597 Australia 20 7.9 13 8.1 29 Europe 404 176 116 224 516 North Am. 339 232 205 114 551 Südam. 214 6.4 35 15.6 57 world 3.670 502 1.830 506 2.838[iii]
With the world population of 3.67 billion people at that time, this results in an average consumption per capita of 773 m³ / year. (Africa 217 m³; North America 1,625 m³).
In 2000 the water consumption worldwide was ~ 5,000 km³ / year. With 6 billion people per capita ~ 833 m³ / year.
Rainwater, which irrigates fields and commercial forests directly, is not taken into account in these figures.
Sources: 2, P. 362; 10, p. 13; http://www.geospot.de/wasserkonflikt/ressource.htm.
The percentage of water consumption is distributed as follows:
Table 4: The water consumption worldwide jn % Agriculture industry household
Countries with low to
middle income 82% 10 % 8 %
Countries with high
Income 30 % 59 % 11 %
EU 21 % 63 % 16 %
World 70 % 22 % 8 %
Source: 10, p. 228.
Between 1940 and 1990, the world's water consumption quadrupled and the population doubled over the same period[iv].
Today, water consumption in industrialized countries has stabilized at a high level.
Developing countries are striving for higher incomes and need more water for this. With an increasing population, they will need similar amounts of water per capita for energy generation, industry and households as the developed countries.
In addition, the demand for water in agriculture will increase sharply, since the yields can be increased significantly through irrigation (Table 5). Currently around 60 % of the agricultural areas are irrigated and around 70 % of the artificially distributed water are used for this.
Table 5: Maximum crop yields through irrigation:
Grain irrigated by rain alone: ~ 3,000 kg / hectare
Optimally irrigated grain ~ 7,500 kg / hectare [v]
Source: 10, p. 205.
Globally, we have the following amounts of water at our disposal, which, however, occur very differently from region to region:
Table 6: Worldwide available water:
Accessible runoff water: 6,780 km³ / year
Rainwater that on fields and
Commercial forests go down: 18,200 km³ / year
Whole, for human needs
Available water: 24,980 km³ / year
Source: 7, p. 9.
From the available water volume of ~ 24,980 km³ / year[vi] a theoretically possible upper limit for the world population can be calculated:
Table 7: Possible world population due to the available Water of 24,980 km³ / year:
Minimum requirement per person for low-meat food, excluding industry 1,100 m³ / year
possible population 22.7 billion
When doubling the minimum requirement
(with industry + better nutrition) 2,200 m³ / year
Possible population 11.4 billion
The theoretically available water is not the only criterion for a natural human population on earth that is already exceeding limits (cf.How many slaves do you make work for you" and "A devastating footprint", Both under" Ecology ").
Are you running out of water?
In many densely populated regions of the world we already have to speak of water scarcity. The precipitation is very unevenly distributed and varies between ~ 0 mm / year (Sahara) and> 11.5 m / year (Mount Waialeale, 1569 m, in Hawaii).
This uneven distribution is somewhat mitigated by the export of “virtual water”. Because with every ton of grain from exporting countries such as Canada or the USA, thousands of tons of virtual water are also indirectly exported. However, the industrialized countries are also introducing 4,000 liters of virtual water with every glass (200 g) of coffee powder (see table in the box).
When will the water shortage have serious effects?
The UN Water Development Report from 2003 (11):
"By the middle of this century, water scarcity will affect 7 billion people in 60 countries in the worst case and 2 billion people in 48 countries in the best case".
A country is considered to be "arid" if the amount of water per capita falls below 1,000 m³ per capita and year. “Tense water situation” is spoken of at 1,770 m³ per capita and year. (9, p. 39).
According to Table 3, the worldwide water consumption, excluding the water that rains directly on the fields, averaged 833 m³ / person + year in 2000. It is noticeable in this table that the regions with high population densities (Africa, Asia, South America) use comparatively little water for industry and energy generation. That will change with the rapid industrial growth in developing countries; the demand for water will increase faster than the population growth.
In the impending battle for water, industry has greater resources, as Edward O. Wilson notes: “One thousand tons of fresh water make one ton of wheat worth approx. US$ 200, - (as of 2002). The same amount of water produces a yield of US$ 14,000 in the industry! "[vii]
The population of 11.4 billion people calculated as possible in Table 7 based on the available water would far exceed the capacity of the earth's water balance in many regions. With rising energy prices, seawater desalination is only used in a few rich countries, e.g. B. the Gulf States, be affordable.
Water shortage is foreseeable!
Water disputes, even wars over water, and mass emigration from countries with water shortages can hardly be prevented.
Table 8: The water required to produce some foods:
Food water requirement in liters:
1 kg of coffee powder 20,000
1 kg of beef 15,000
1 kg of lamb 10,000
1 kg poultry 8,000
1 kg of cheese 5,000
1 kg of sugar 3,000
1 kg of rice 2,000 - 5,000
1 kg of palm oil 2,000
1 kg of wheat 1,000 - 1,500
1 kg of citrus fruits 1,000
1 kg of legumes 1,000
1 kg of bread 1,000
1 kg of potatoes 500
1 liter of milk 2,000 - 4,000
1 liter of orange juice 1,000
1 liter of beer 500
1 cup of coffee 140
1 egg 1,000
Sources: 4, p. 440; 5, p. 17 f .; 9, p. 203.
Table 9: The water of our blue planet:
Total water supply on earth: 1.38 billion km³
Thereof freshwater 35.88 million km³ (2.6 %)
On a smooth globe, water would cover the land evenly at a height of 2.7 km. The fresh water alone could cover the earth with a depth of 70 m.
Sources: 1, p. 27; 9, p. 54 f.
1 km³ = 1 billion (109) m³ = 1 trillion (1012) Liters
1 m³ = 1,000 liters
(1) Barandat Jörg, water - confrontation or cooperation, Nomos, Baden-Baden, 1997.
(2) Global 2000 The Report to the President, Zweiausendeins, Frankfurt, 1981.
(3) Heinrich Dieter / Herget Manfred, dtv-Atlas zur Ökologie, dtv, Munich, 1990.
(4) Kürschner-Polkmann Frank, Das Wasser-Buch, Lembeck, Frankfurt a. M .; 2007.
(5) Pearce Fred, When the rivers dry up, Antje Kunstmann, Munich, 2007.
(6) Polkehn Klaus, War for Water ?, Morgenbuch, Berlin, 1992.
(7) Rogers Peter P., Water Crisis, Taylor & Francis, London, 2006.
(8) Shiva Vandana, The Battle for Blue Gold, Red Dot, 2007.
(9) Villiers Marq de, Wasser, Econ, Munich, 2000.
(10) Water for People - Water for Life, The United Nations World Water Report, UNESCO-WWAP, 2003.
(11) http://www.aktiongrundwasserschutz.de/informationen /weltweit/index.htm.
[i] There are now promising processes for producing liquid fuels from wood or, in the future, even from algae. There is hope that the oil crisis can be stopped. However, not immediately and not for free.
[ii] Worldwide there are over 300 river systems that affect several countries.
[iii] The world population of 3.67 billion named in "Global 2000" for 1977 seems too small. From today's perspective, over 4 billion are more accurate.
[v] Such peak yields require high-performance grain varieties, which in turn require abundant water and artificial fertilization. Often unaffordable for poor farmers in underdeveloped countries!
[vi] This amount of water should be at the upper limit. Another source (see footnote 4) states that the directly available amount of water is only 9,000 km³. The maximum population on earth would then be 8 billion with a modest standard of living; with industry with high demands only at 4 billion!
[vii] Edward O. Wilson, “The Future of Life”, Goldmann, Munich, 2004, p. 62.