The water cycle, also called the hydrological cycle, is a life cycle that involves the continuous circulation of water in the Earth-atmosphere system. Of the many processes involved in the water cycle, the most important are evaporation, transpiration, condensation, precipitation and runoff. Although the total amount of water within the cycle remains essentially constant, its distribution among the various processes changes continuously.
It is the sequence of environmental phenomena through which water can reach the earth's surface, and the atmosphere in the vapor phase, returning again in its liquid and solid phases.
The hydrological cycle consists of the process by which water is mobilized inside and outside the Earth. It happens because water is in motion, changing state and for this reason we find water in liquid, solid or gaseous state. The water cycle does not have a starting point, but the oceans are always taken as this one, since it is there where the greatest amount of water on Earth is found.
It begins when a portion of the water in the oceans evaporates through sunlight. This light heats the water and causes it to change state, evaporating and passing into the atmosphere along with the air. A part of this vapor comes directly from the solid state when pieces of ice and snow are subjected to a state of sublimation.
When air currents rise, water vapor goes into the atmosphere including water vapor from oceans, ice, snow, and some other sources. The steam then rises to the highest part of the atmosphere, where the air is cooler. With this phenomenon, water condenses in the form of clouds. The different water currents cause particles from the clouds to collide, grow and fall to the ground in the form of precipitation.
The hydrological cycle is essential to maintain the balance of the earth’s ecosystems, and to be able to provide fresh and pure water to all living beings, thanks to the recirculation of this vital liquid. All forms of water are considered to participate in the water cycle, which is indispensable for the development of life on planet Earth. Basically, life without water would be impossible.
The components of water are as follows:
The stages of the hydrological cycle are as follows:
Climate models show that water will heat up depending on greenhouse gas levels. These changes will affect the quality and quantity of water available to humans and the environment. It is possible that when this happens, water quality will be affected, droughts will increase, and the intensity and frequency of rainfall will change drastically.
The function of the natural water cycle is to be an essential resource for life with strategic economic value. The natural cycle provides regions with many initial potentialities and limitations, and its availability is a prerequisite for the development of social and economic activities.
Some of the effects that can be observed by the hydrological cycle are:
The hydrological cycle is a vital process for sustaining life on earth. It is through it that water is provided to all the planet’s ecosystems and to the living beings that need it in order to survive. It allows the growth of plants, the purification of terrestrial and aquatic waters, and, through evaporation, the pollutants are eliminated in order to turn the water into drinking water.
If we did not have the water cycle, substances that are harmful to health would progressively accumulate and water could no longer be consumed by humans or animals.