How long will we have enough drinking water on Earth? Fresh water reserves on Earth: approximate volumes, the problem of water shortage, interesting facts

More than 98% of all water resources The Earth is made up of salty waters of the oceans, seas, etc. The total volume of fresh water on Earth is 28.25 million km3, or about 2% of the total volume of the hydrosphere. The bulk of fresh water is concentrated in glaciers, the waters of which are still used very little. The rest of the fresh waters suitable for water supply account for 4.2 million km3 of water, or only 0.3% of the volume of the hydrosphere.

The hydrosphere plays a huge role in the formation natural environment of our planet. It also has a very active influence on atmospheric processes(heating and cooling of air masses, saturating them with moisture, etc.).

Atmosphere ( Greek “atmos”  steam)  gaseous envelope of the Earth, consisting of a mixture various gases, water vapor and dust (Table 6.3, according to N. Reimers, 1990). The total mass of the atmosphere is  5.15  1015 tons. At an altitude of 10 to 50 km, with a maximum concentration at an altitude of 20–25 km, there is an ozone layer that protects the Earth from excessive ultraviolet radiation, which is fatal to organisms.

Table 6.3

Atmospheric composition

The atmosphere physically, chemically and mechanically affects the lithosphere, regulating the distribution of heat and moisture. Weather and climate on Earth depend on the distribution of heat, pressure and water vapor content in the atmosphere. Water vapor absorbs solar radiation, increases air density and is the source of all precipitation. The atmosphere is supportive various shapes life on Earth.

In the formation of the Earth’s natural environment, the role of the troposphere (the lower layer of the atmosphere up to a height of 8–10 km in polar, 10–12 km in temperate and 16–18 km in tropical latitudes) and, to a lesser extent, the stratosphere, a region of cold rarefied dry air approximately 20 km. Meteorite dust continuously falls through the stratosphere, volcanic dust is thrown into it, and in the past, products nuclear explosions in the atmosphere.

In the troposphere, global vertical and horizontal movements of air masses occur, which largely determine the water cycle, heat exchange, and transboundary transport of dust particles and pollution.

Atmospheric processes are closely related to processes occurring in the lithosphere and water shell.

TO atmospheric phenomena include: precipitation, clouds, fog, thunderstorm, ice, dust (sand) storm, squall, blizzard, frost, dew, hoarfrost, icing, aurora, etc.

The atmosphere, hydrosphere and lithosphere interact closely with each other. Almost all superficial, exogenous, geological processes are caused by this interaction and take place, as a rule, in the biosphere.

Biosphere the outer shell of the Earth, which includes part of the atmosphere up to a height of 25–30 km (up to the ozone layer), almost the entire hydrosphere and the upper part of the lithosphere to a depth of approximately 3 km. The peculiarity of these parts is that they are inhabited by living organisms that make up living matter planets. Interaction of the abiotic part of the biosphere  air, water and rocks, and organic matter biota, determined the formation of soils and sedimentary rocks. The latter, according to V.I. Vernadsky, bear traces of the activity of ancient biospheres that existed in past geological eras.

19. World water resources

The concept of water resources can be interpreted in two senses – broad and narrow.

IN in a broad sense- this is the entire volume of water in the hydrosphere contained in rivers, lakes, glaciers, seas and oceans, as well as in underground horizons and in the atmosphere. The definitions huge, inexhaustible are quite applicable to it, and this is not surprising. After all, the World Ocean occupies 361 million km2 (about 71% of the total area of ​​the planet), and glaciers, lakes, reservoirs, swamps, and rivers account for another 20 million km2 (15%). As a result, the total volume of the hydrosphere is estimated at 1390 million km3. It is not difficult to calculate that with such a total volume, each inhabitant of the Earth now has approximately 210 million m3 of water. This amount would be enough to supply large city for a whole year!

However, it is necessary to take into account the possibilities of using these enormous resources. Indeed, of the total volume of water contained in the hydrosphere, 96.4% falls on the share of the World Ocean, and of the water bodies on land, the largest amount of water contains glaciers (1.86%) and groundwater (1.68%), the use of which is possible, but more partly very difficult.

That is why, when we talk about water resources in the narrow sense of the word, we mean fresh water suitable for consumption, which constitutes only 2.5% of the total volume of all waters in the hydrosphere. However, significant adjustments must be made to this indicator. One cannot ignore the fact that almost all fresh water resources are “conserved” either in the glaciers of Antarctica, Greenland, mountainous regions, in the ice of the Arctic, or in groundwater and ice, the use of which is still very limited. Lakes and reservoirs are used much more widely, but their geographical distribution is by no means ubiquitous. It follows that the main source of meeting humanity’s needs for fresh water has been and remains river (channel) water, the share of which is extremely small, and the total volume is only 2100 km3.

This amount of fresh water would not be enough for people to live by now.

However, due to the fact that the duration of the conditional moisture cycle for rivers is 16 days, during the year the volume of water in them is renewed on average 23 times and, therefore, the river flow resources can be purely arithmetically estimated at 48 thousand km3/year. However, the prevailing figure in the literature is 41 thousand km3/year. It characterizes the “water ration” of the planet, but reservations are also necessary here. It is impossible not to take into account that more than half of the channel waters flow into the sea, so that the resources of such waters actually available for use, according to some estimates, do not exceed 15 thousand km3.

If we consider how the total river flow is distributed between large regions of the world, it turns out that foreign Asia accounts for 11 thousand km3, South America - 10.5, North America - 7, CIS countries - 5.3, Africa – 4.2, for Australia and Oceania – 1.6 and for foreign Europe – 1.4 thousand km3. It is clear that behind these indicators are primarily the largest river systems in terms of flow: in Asia - the Yangtze, Ganges and Brahmaputra, in South America– Amazon, Orinoco, Parana, in North America – Mississippi, in the CIS – Yenisei, Lena, in Africa – Congo, Zambezi. This fully applies not only to regions, but also to individual countries (Table 23).

Table 23

TOP TEN COUNTRIES BY SIZE OF FRESHWATER RESOURCES

Figures characterizing water resources cannot yet give a complete picture of water availability, since the provision of total flow is usually expressed in specific indicators - either per 1 km2 of territory or per inhabitant. This water supply to the world and its regions is shown in Figure 19. Analysis of this figure suggests that with a global average of 8000 m3/year, Australia and Oceania, South America, the CIS and North America, and below – Africa, foreign Europe and foreign Asia. This situation with water supply in the regions is explained as follows: overall dimensions their water resources and the size of their population. No less interesting is the analysis of differences in water availability in individual countries (Table 24). Of the ten countries with the greatest water availability, seven are located within the equatorial, subequatorial and tropical zones, and only Canada, Norway and New Zealand– within the temperate and subarctic.

Rice. 19. Availability of river flow resources according to large regions world, thousand m3/year

Table 24

COUNTRIES WITH THE HIGHEST AND LEAST AVAILABILITY OF FRESHWATER RESOURCES

Although based on the above per capita indicators of water availability for the whole world, its individual regions and countries, it is quite possible to imagine its general picture, it would be more correct to call such availability potential. To imagine the real water availability, you need to take into account the size of water intake and water consumption.

World water consumption in the twentieth century. grew as follows (in km3): 1900 – 580, 1940 – 820, 1950 – 1100, 1960 – 1900, 1970 – 2520, 1980 – 3200, 1990 – 3580, 2005 - 6000. These general indicators of water consumption are very important: they indicate that throughout the 20th century. global water consumption increased 6.8 times. Already, almost 1.2 billion people do not have access to clean drinking water. According to the UN forecast, universal access to such water can be achieved: in Asia - by 2025, in Africa - by 2050. The structure, i.e., the nature of water consumption, is no less important. Nowadays, 70% of fresh water is consumed by agriculture, 20% by industry, and 10% goes to meet domestic needs. This ratio is quite understandable and natural, but from the point of view of saving water resources, it is quite unprofitable, primarily because in agriculture (especially in irrigated agriculture) irrecoverable water consumption is very high. According to available estimates, in 2000

Distribution of water resources on the planet

irrecoverable water consumption in world agriculture amounted to 2.5 thousand km3, while in industry and public utilities, where recycled water supply is more widely used, respectively, only 65 and 12 km3. From all that has been said, it follows, firstly, that today humanity already uses quite a significant part of the planet’s “water ration” (about 1/10 of the total and more than 1/4 of the actually available) and, secondly, that irreversible water losses amount to more than 1/2 of its total consumption.

It is no coincidence that the highest rates of per capita water consumption are characteristic of countries with irrigated agriculture. The record holder here is Turkmenistan (7000 m3 per person per year). It is followed by Uzbekistan, Kyrgyzstan, Kazakhstan, Tajikistan, Azerbaijan, Iraq, Pakistan, etc. All these countries are already experiencing a significant shortage of water resources.

In Russia, the total river flow reaches 4.2 thousand km3/year, and, therefore, the resource availability of this flow per capita is 29 thousand m3/year; This is not a record, but quite a high figure. Total fresh water intake in the second half of the 1990s. due to economic crisis tended to decrease slightly. In 2000 it was 80–85 km3.

The structure of water consumption in Russia is as follows: 56% is used for production, 21% for household and drinking needs, 17% for irrigation and agricultural water supply, and 6% for other needs. It is easy to calculate that in Russia as a whole, the total water intake is only 2% of shared resources river flow. However, this is an average figure, and in some river basins it reaches 50–75% or more. The same applies to individual economic regions of the country. Thus, in the Central, Central Chernozem and Volga regions, water availability per capita is only 3000–4000 m3/year, and in the Far East – 300 thousand m3.

The general trend for the whole world and its individual regions is a gradual decrease in water availability, therefore, various ways to save water resources and new ways of water supply are being sought.

Date: 2016-04-07

How much fresh water is left on the planet?

Life on our planet originated from water, human body 75% consists of water, so the issue of fresh water reserves on the planet is very important. After all, water is the source and stimulant of our life.

Fresh water is considered to be water that contains no more than 0.1% salt. Moreover, it does not matter what state it is in: liquid, solid or gaseous.

World fresh water reserves

97.2% of the water that is on planet earth belongs to salty oceans and seas. And only 2.8% is fresh water. On the planet it is distributed as follows:

• 2.15% of water reserves are frozen in the mountains, icebergs and ice sheets of Antarctica;
• 0.001% of water reserves are in the atmosphere;
• 0.65% of water reserves are in rivers and lakes. This is where people take it for their consumption.

In general, it is believed that fresh water sources are endless. Because the process of self-healing constantly occurs as a consequence of the water cycle in nature. Every year, as a result of the evaporation of moisture from the world's oceans, a huge supply of fresh water (about 525,000 km3) is formed in the form of clouds. A small portion does end up back in the ocean, but most falls on the continents in the form of snow and rain and then ends up in lakes, rivers and groundwater.

Freshwater consumption in different parts of the planet

Even such a small percentage of available fresh water could cover all the needs of humanity if its reserves were evenly distributed throughout the planet, but this is not the case.

The Food and Agriculture Organization of the United Nations (FAO) has identified several areas whose water consumption levels exceed the amount of renewable water resources:

• Arabian Peninsula. For public needs, they use five times more fresh water than is available. natural sources. Water is exported here using tankers and pipelines, and desalination procedures are carried out sea ​​water.
• Water resources in Pakistan, Uzbekistan and Tajikistan are under stress. Almost 100% of renewable water resources are consumed here. More than 70% of renewable water resources are produced by Iran.
• Fresh water problems also exist in North Africa, especially in Libya and Egypt. These countries use almost 50% of water resources.

The greatest need is not in countries with frequent droughts, but in those with high population densities. You can see this using the table below. For example, the most large area Asia has water resources, and Australia has the smallest. But at the same time, every resident of Australia is provided with drinking water 14 times better than anyone in Asia. This is because Asia has a population of 3.7 billion, while Australia has only 30 million.

Problems of fresh water use

Over the past 40 years, the amount of clean fresh water per person has decreased by 60%. Agriculture is the largest consumer of fresh water. Today, this sector of the economy consumes almost 85% of the total volume of fresh water used by humans. Products grown using artificial irrigation are much more expensive than those grown on soil and irrigated by rain.

More than 80 countries around the world experience a shortage of fresh water. And every day this problem is becoming more acute. Water scarcity even causes humanitarian and government conflicts. Improper use of groundwater leads to a decrease in its volume. Every year these reserves are depleted by 0.1% to 0.3%. Moreover, in poor countries, 95% of water cannot be used for drinking or food at all due to high level pollution.

The need for clean drinking water increases every year, but its quantity, on the contrary, is only decreasing. Almost 2 billion people have limited water consumption. According to experts, by 2025, almost 50 countries of the world, where the number of inhabitants will exceed 3 billion people, will experience the problem of water shortage.

In China, despite a large number of precipitation, half the population does not have regular access to sufficient drinking water.

Distribution of waters on Earth

Groundwater, like the soil itself, is renewed too slowly (about 1% per year).

The issue of the greenhouse effect remains relevant. Climate condition The earth is constantly deteriorating due to constant release into the atmosphere carbon dioxide. This causes an abnormal redistribution of atmospheric precipitation, the occurrence of droughts in countries where they should not occur, snowfall in Africa, high frosts in Italy or Spain.

Such abnormal changes can cause a decrease in crop yields, an increase in plant diseases, an increase in pest populations and various insects. The planet's ecosystem is losing its stability and cannot adapt to such a rapid change in conditions.

Instead of results

In the end, we can say that there are enough water resources on planet Earth. The main problem with water supply is that these supplies are unevenly distributed on the planet. Moreover, 3/4 of fresh water reserves are in the form of glaciers, which are very difficult to access. Because of this, some regions are already experiencing a shortage of fresh water.

The second problem is the contamination of existing accessible water sources with human waste products (salt heavy metals, petroleum products). Clean water that can be consumed without preliminary purification can only be found in remote ecologically clean areas. But densely populated regions, on the contrary, suffer from the inability to drink water from their meager supplies.

Water resources include all usable surface and underground waters of the Earth. Water is necessary to maintain organic life on Earth, the existence of man, his economic activity. The water factor has a great influence on the location of social production. Water-intensive industries with a focus on large sources of water supply include many industries (electric power, ferrous and non-ferrous metallurgy, pulp and paper, chemical industry, etc.), agriculture (rice growing, cotton growing, etc.). Water resources are an extremely important factor not only for obviously water-intensive industries, but also for the development of cities and meeting the household needs of the population.

People's needs for fresh water are especially great, the reserves of which are limited on Earth. The total water reserves on Earth, forming its hydrosphere (oceans and seas, rivers, lakes, swamps and reservoirs, groundwater, glaciers and snow, soil moisture and atmospheric vapor), are estimated at 1,386 million cubic meters. km. Of these, 96.5% of water resources come from the salty waters of the World Ocean and 1% from salty groundwater. The remaining 2.5% of the volume of the hydrosphere constitutes the fresh water resources on the globe.

However, in reality their number is much smaller (only 0.3% of the volume of the hydrosphere), since polar ice As a source of fresh water, they are practically not yet used.

Thus, despite the presence of enormous water resources on Earth, the amount suitable for immediate practical use(fresh water) is very limited.

Among the few sources of fresh water, rivers are the main ones. River water resources are renewable and inexhaustible, unlike underground fresh water, the reserves of which are exhaustible. The amount of annually renewable water resources is estimated by the size of river flow, which depends on the relationship between precipitation (falling in the form of rain and snow on the surface of the river basin) and evaporation of the fallen moisture.

River water resources (river flow resources) are estimated at 47 thousand cubic meters. km per year, and the world average river flow (flow per capita) is about 8 thousand cubic meters. m/year.

More than half of the fresh water resources from the planet's river runoff are in Asia (13,190 cubic km per year), where such large rivers of the Earth as the Yangtze, Irrawaddy, Mekong, Ganges, Brahmaputra, and South America flow (10,380 cubic km/ year) with its greatest river (by flow volume, basin area, length and width) the Amazon. The other half of the total volume of river flow is shared between North America (5,960), Africa (4,225), Europe (3,110), Australia and Oceania (1,965 cubic km/year). Australia and Oceania, which are in last place on this list, at the same time have the highest water supply per capita (83 thousand cubic meters / year), and Asia, which leads in fresh water reserves, has the lowest average water supply per capita - 4.5 thousand cubic meters m/year. In South America this figure is 34 thousand cubic meters. m/year, in Northern - 15, in Africa - 6.5, in Europe — b thousand cubic meters m/year. Water availability varies significantly across countries around the world. Russia has significant fresh water resources. The total volume of its river flow is estimated at 4,270 cubic meters. km/year, which is about 10% of the total flow of all rivers in the world. According to this indicator, following Brazil, Russia surpasses all countries in the world. Russia's water supply per capita (28.5 thousand cubic meters/year) is more than three times higher than the world average. Water resources within the country are distributed extremely unevenly - about 70% of its total surface runoff falls on sparsely populated, economically underdeveloped regions of Siberia and Far East and only 30% - for the densely populated and most water-intensive areas of the European part and the Urals.

Distribution of water on Earth and its cycle. Water balance

The worst provision of water is in the central regions (Lipetsk, Belgorod, Kursk and Voronezh region) and southern (Rostov, Astrakhan region, Republic of Kalmykia, etc.) areas of the European part.

In Russia there are about 120 thousand.

rivers (over 10 km long), most of them belong to the basins of the Arctic (Northern Dvina, Pechora, Ob with Irtysh, Yenisei, Lena, Indigirka, Kolyma, etc.), Pacific (Amur, Anadyr, Penzhina, etc.) and Atlantic (Don, Kuban, Neva) oceans. One of the largest and most abundant rivers in Russia, the Volga belongs to the internal drainage basin and flows into the Caspian Sea. A significant volume of fresh water is contained in reservoirs (of which Bratskoye, Krasnoyarsk, Zeyskoye, Ust-Ilimskoye, Samara are among the largest in the world) and lakes (Baikal - the deepest lake in the world, Ladoga, Onega, Taimyr, etc.). Russia is also rich in fresh groundwater resources, the exploitable reserves of proven deposits amount to 27.3 cubic meters. km/year, of which 80% are located in the European part.

In general, water consumption in the world is constantly growing and in 2000 it amounted to 4,780 cubic meters. km, i.e. approximately 10% of the total freshwater resources (total annual flow) of the planet. The main consumers of water in the world are agriculture (69%), industry (21%), public utilities (6%) and reservoirs. At the same time, the share of water used in agriculture and municipal services is constantly increasing.

In Russia, about 100 cubic meters are used annually. km of fresh water (in the USA - 550 cubic km), or approximately 2.4% of its total annual river flow. In the structure of water consumption, in contrast to the world average, the leading role is played by industry (55%), the share of agriculture is low (20%) and the public sector is high (19%).

IN last years In many countries of the world, a shortage of water resources began to be felt, associated not with their depletion, but with the qualitative deterioration of natural surface waters- their contamination as a result of use in everyday life and at work. The volume of contaminated surface water is so large that the problem clean water has become global.

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Fresh water makes up no more than 2.5-3% of the Earth's total water supply. Its bulk is frozen in glaciers and snow cover in Antarctica and Greenland. Another part is numerous fresh water bodies: rivers and lakes. A third of fresh water reserves are concentrated in underground reservoirs, deep and closer to the surface.

At the beginning of the new millennium, scientists began to seriously talk about the shortage of drinking water in many countries of the world. Every inhabitant of the Earth should spend from 20 to water per day on food and personal hygiene. However, there are countries where there is not enough drinking water to even sustain life. Residents of Africa are experiencing severe water shortages.

Reason one: increase in the Earth's population and development of new territories

According to the UN, in 2011 the world's population grew to 7 billion people. The number of people will reach 9.6 billion by 2050. Population growth is accompanied by the development of industry and agriculture.

Enterprises use fresh water for all production needs, while returning water that is often no longer suitable for drinking to nature. It ends up in rivers and lakes. The level of their pollution has recently become critical for the ecology of the planet.

Agricultural development in Asia, India and China has depleted the largest rivers in these regions. The development of new lands leads to shallowing of water bodies and forces people to develop underground wells and deep-sea horizons.

Reason two: irrational use of fresh water sources

Most natural fresh water sources are replenished naturally. Moisture enters rivers and lakes with precipitation, some of which goes into underground reservoirs. Deep-sea horizons are classified as irreplaceable reserves.

The barbaric use of clean fresh water by humans is depriving rivers and lakes of their future. Rains do not have time to fill shallow reservoirs, and water is often wasted.

Some of the water used goes underground through leaks in urban areas. water supply networks. When turning on the tap in the kitchen or shower, people rarely think about how much water is wasted. The habit of saving resources has not yet become relevant for the majority of the Earth's inhabitants.

Extracting water from deep wells can also be a big mistake, depriving future generations of the main reserves of fresh water. natural water, and irreparably disrupt the ecology of the planet.

Modern scientists see a way out in saving water resources, tightening control over waste processing and desalinating sea salt water. If humanity thinks about it now and takes action in time, our planet will forever remain an excellent source of moisture for all species of life existing on it.

At the end of February, world oil prices showed a slight decline after five days of growth. However, prices remain near 10-month highs amid rising tensions over Iran's nuclear program. The dependence of the global financial system on the cost of energy resources is becoming increasingly obvious. Also, due to the increase in population, there is a growing shortage of other resources that ensure the life of humanity: food and fresh water. Service analytical information International organization creditors (WOC) conducted a study to determine how long humanity will have enough natural resources and how their shortages affect the global economy.

In the 70s last century, humanity's needs began to exceed the planet's ability to renew resources. Now, according to ecologists, it takes the Earth 1.5 years to reproduce what humanity consumes in a year.

“In recent years, about 25% and 20% of the planet’s resources were used by the United States and China. Accordingly, the remaining countries accounted for a little more than half of the Earth’s available reserves,” says WOC President Robert Abdullin. “Maintaining the life of the average American, for example, takes 3. 5 times more than the average per inhabitant of the Earth, and 9 times more than per 1 inhabitant of India or almost any African country."

In the context of significant population growth, both in the world as a whole and in individual countries, issues of availability of resources such as energy, water and food become relevant.

Energy resources

According to OPEC, developing countries control 2/3 of the world's oil reserves, the resource most needed by humanity, which is rapidly depleting. The largest share of the world's oil reserves is located in Saudi Arabia and Venezuela. Russia is in 8th place according to this indicator. When recalculating reserves per capita, Kuwait becomes the leader, followed by the UAE and Qatar. At the current volumes of proven reserves and production volumes, humanity will have enough oil for no more than 50 years. In Russia, oil, at current production volumes, may run out in 21 years.

By reserves natural gas in first place in the world is Russian Federation(47.5 trillion m3), followed by a significant margin by Iran and Qatar (29.6 trillion m3 and 25.4 trillion m3, respectively). With the current volumes of proven reserves and production volumes, this type of fuel will last humanity for just over 60 years. In Russia, natural gas reserves, other things being equal, will last almost 80 years.

Food

Population growth and, accordingly, an increase in demand for food resources provoke an increase in prices.

In terms of the availability of agricultural land and forest areas per capita, Russia is the undisputed leader among the countries considered, followed by Brazil and the United States. China and India are outsiders due to their high population density. In absolute terms, China's agricultural area is more than double that of Russia. As for the volume of grain produced, in per capita terms the United States is the leader, followed by Russia. The US leadership is explained by very high productivity in agriculture: grain yields in America are three times higher than, for example, in Russia.

Water

The leader in the availability of total renewable water resources among the countries considered is Brazil (8,233 billion m3 per year), followed by Russia (4,505 billion m3 per year). In India, this figure is 1,911 billion m3 per year, in Egypt this figure is much lower - 57 billion m3 per year. Brazil also ranks first in terms of the availability of total renewable water resources per capita (42,604 m3 per person per year), followed by the Russian Federation (31,511 m3 per person per year). For the USA, the figure is three times lower than for Russia. The low value of this indicator in China and India is explained by high density population, and in Egypt - the limited water resources of the region.

The growing shortage of energy, food and fresh water is a serious challenge for humanity. We must take into account that the world's population is growing: by 2025, according to UN forecasts, there will already be 8 billion of us. At the same time, there will be enough oil for the next 50 years, and natural gas for 60. The influence of states with sufficient reserves of natural resources on the world economy intensifies. This means that we are on the verge of a global turning point and a redistribution of vectors of influence on the planet.

Water reserves in the world. List of countries by water resources

A list of 173 countries of the world is presented, ordered by the volume of total renewable water resources according to data [. Data include long-term average renewable water resources (in cubic kilometers of precipitation, renewable groundwater, and surface inflows from neighboring countries.

Brazil has the largest renewable water resources - 8,233.00 cubic kilometers. Largest reserves in Europe and second in the world is Russia - 4,508.00. Next is the USA - 3,069.00, Canada - 2,902.00 and China - 2,840.00. Full table- see below.

Fresh water. Reserves[Source - 2].

Fresh water- the opposite of sea water, covers that part of the available water of the Earth in which salts are contained in minimum quantities. Water whose salinity does not exceed 0.1%, even in the form of steam or ice, is called fresh. Polar ice sheets and glaciers contain the largest portion of the earth's fresh water. In addition, fresh water exists in rivers, streams, groundwater, fresh lakes, and also in clouds. According to various estimates, the share of fresh water in total number water on Earth is 2.5-3%.

About 85-90% of fresh water is contained in the form of ice. Distribution of fresh water across to the globe extremely uneven. Europe and Asia, where 70% of the world's population lives, contain only 39% of river waters.

In terms of surface water resources, Russia ranks leading place in the world. About 20% of the world's lake fresh water reserves and more than 80% of Russia's reserves are concentrated in the unique Lake Baikal alone. With a total volume of 23.6 thousand km³, about 60 km³ of rare purity natural water is reproduced in the lake annually.

According to the UN, at the beginning of the 2000s, more than 1.2 billion people live in conditions of constant fresh water shortage, and about 2 billion suffer from it regularly. By the middle of the 21st century, the number of people living with constant water shortages will exceed 4 billion people. In such a situation, some experts say that Russia’s main advantage in long term perspective- water resources.

Fresh water reserves: atmospheric vapor - 14,000 or 0.06%, river fresh water - 200 or 0.005%, total Total 28,253,200 or 100%. Sources - Wikipedia: , .

List of countries by water resources[Source - 1]

Looking at the world map, it seems to us that there is plenty of water, and there is no need to save it, especially since 75% of land is covered with water. But we all know that a person can only consume fresh water, and there is not much of it, only 2.5% of the total volume of water. This 2.5% includes: rivers, lakes, glaciers, precipitation (rain and snow). And it is important for us to learn to save water and use it rationally, otherwise the water cycle in nature may be disrupted. The water will not have time to evaporate, undergo the purification process and return to us. Accordingly, water reserves will become less and less.

A Humanity needs a lot of water. Every person needs water, he needs to eat, wash. Considering that the world's population is constantly increasing, it is worth considering! For example, a resident of Singapore consumes per day 250 liters, Tashkent resident - 560 liters, in Israel the average norm per person is 140 liters, but 90 liters dirty water cleaned and sent for irrigation. This good example rational use of water.

Don’t forget about domestic and wild animals; if a tiny hummingbird needs a few milligrams of water a day, a relatively small herd of elephants can drink up an entire lake. Besides, agriculture a huge amount of water is required. As the saying goes: no water - no food. It is known that to obtain one kilogram of rice, it takes 3 tons of water, a kilogram of wheat is a little more than a ton, and a kilogram of beef will require 16 tons of fresh water. And in order to enjoy one cup of coffee, it costs 140 liters of water.

This does not include cleaning premises, watering gardens, washing cars, sidewalks and toilets. It’s hard to calculate how much water we lose due to faulty taps! Humanity can only use one percent of the world's surface or underground freshwater resources. Modern scientists have calculated that in the next quarter of a century, humanity will begin to experience an acute shortage of water.

According to science, 9 3% of all atoms in the Universe are hydrogen atoms- gas that produces water. At the same time, for the entire human history, we have not yet learned all the secrets that water holds, nor have we explored its amazing properties. Until now, scientists are puzzling over the question: why frozen water turns into snowflakes of beautiful shapes, and each snowflake has its own pattern, not similar to the others.

In nature, all substances expand when heated and tend to contract when cooled. Water regularly follows this rule, but only to a certain limit. Water contracts while it is cooled to 4°C. It should be noted that at this temperature water has maximum density, and therefore weight. With further cooling it expands. At zero, when it freezes, it turns into ice, and its expansion proceeds spasmodically, and the volume increases by about a tenth of its original volume.

Therefore, the ice turns out to be slightly lighter than water and floats to its surface. This feature of water has special meaning for all inhabitants of the Earth. If water were compressed at a temperature below 4°C, then the ice would sink to the bottom, over time all reservoirs would freeze through and there would be no life in the reservoirs. Freezing of water would lead to a sharp reduction in the rate of evaporation of water, hence the amount of precipitation would decrease. The climate of the planet would change dramatically, but thanks to the special properties of water, our world exists.

The climate of our planet depends on other amazing properties water has a very high heat capacity. In terms of heat capacity, water is ten times greater than iron. Water retains this property in the form of ice and steam. Every day, accumulating heat during daylight hours, huge masses of water in the seas and oceans create a climate suitable for life. Water having great strength surface tension, is therefore inferior to the parameter only mercury. Therefore, mercury in free fall takes the form of balls that stretch slightly due to air resistance.

Water has the ability to stick to other substances, wetting them. Water is a unique solvent, and this is another wonderful property water. Understanding the characteristics of water, we can imagine how water influenced and influences the substances contained in the earth’s crust. They often say: “ Water wears away stones" Myriads of drops, the mass of which is multiplied by the force of surface attraction, have been hollowed out and deformed for many centuries rocks earth's crust. Considering that water collects heat and releases it, alternately heating and cooling the substances with which the water comes into contact, it had a destructive effect on earth's crust. Big mechanical work, done by water, was supplemented by mechanical, water dissolved everything it could. Water stuck to solid particles, carried them along with it into streams, rivers and carried them into the ocean.