More than 70% of the planet is covered by water.
From the Latin aqua , water is a substance whose molecules are composed of one oxygen atom and two hydrogen atoms . It is an odorless (odorless), tasteless (flavorless) and colorless (colorless) liquid, although it can also be found in a solid state (when it is known as ice ) or in a gaseous state ( vapor ).
Water is the most abundant component on the Earth's surface (it covers about 71% of the Earth 's crust). It forms the oceans, rivers and rain, as well as being a constituent part of all living organisms. The circulation of water in ecosystems occurs through a cycle consisting of evaporation or transpiration, precipitation and movement towards the sea.
Types of water: fresh, drinkable, salt and mineral
Fresh water is water that contains a minimum amount of dissolved salts (unlike sea water, which is salty ). Through a purification process, humans can convert fresh water into drinkable water , that is, water suitable for consumption thanks to the balanced value of its minerals. It is important to note that the shortage of drinking water in many regions of the planet causes more than 5 million deaths per year.
Mineral water , as its name suggests, contains minerals and other dissolved substances, which add therapeutic value or alter the taste. This type of water is sold in bottles all over the world for human consumption.
The problem of scarcity
Water scarcity is a problem that occurs everywhere on the planet . About 20% of the world's population lives in areas where there is not enough water, and another 10% is close to that situation. On the other hand, 25% must deal with the lack of resources in their country to transport water from aquifers and rivers.
Lack of access to drinking water is a global problem.
For many, water scarcity has become one of the most urgent issues to be resolved in the 21st century, partly due to the excessive consumption that took place over the previous hundred years, which has doubled the birth rate. While it is not correct to say that the entire Earth suffers from a lack of water, the number of areas lacking this vital resource is growing at an alarming rate.
Human responsibility for the lack of water
As is well known, the action of our species is largely responsible for this phenomenon: the amount of drinking water present in the entire world is sufficient to supply us all; however, given the irregularity with which it is distributed and the enormous waste by a large percentage of the population, its management becomes unsustainable.
Hydrology typically uses the relationship between water and population to measure scarcity. Scarcity occurs when the annual water supply to a region decreases by 1,000 cubic meters per person; water stress occurs when the decrease is 1,700 cubic meters. Absolute scarcity occurs when each individual has access to less than 500 cubic meters per year.
In other words, water scarcity occurs when the demand for water cannot be met, either because of its quantity or quality. It is important to remember that water is not only used for drinking, but that humans have given it other uses, which also come into the equation.
For this reason, scarcity is a relative concept, a phenomenon that can arise from excessive demand in an environment that could well supply real needs, or from the lack of the minimum necessary for the life of its users.