Water is a renewable resource because the water cycle repeats itself over and over again naturally, without the need for human intervention. The water cycle (or hydrological cycle) is the process of water circulation in the hydrosphere. Basically, water moves from one place to another through state transformations.
The water or hydrological cycle is divided into several stages. In each one of them, the water presents a different state but is never consumed or disappears, but circulates.
Water is a renewable resource but not unlimited
That is why water is considered a renewable resource compared to others that are not because once used or consumed, its useful life ends and there are no infinite reserves of them.
What are the phases of the water cycle?
The water cycle implies the existence of different processes through its phases or stages. The most important are the following:
Evaporation
Water evaporates in the oceans and seas with sunlight and rises into the atmosphere forming clouds. This is considered a second stage of the water cycle known as condensation.
Precipitation
The water, accumulated in the clouds, falls on the Earth in the form of drops of water (rain), flakes (snow) or pebbles (hail), depending on the temperature.
Infiltration
In this phase of the cycle, water penetrates the soil when it is permeable. Once infiltrated, it returns to the atmosphere by evaporation or through the transpiration of plants. Plants use this water through their roots.
Runoff
It is the circulation of water on the surface once precipitated. Depending on the topographic characteristics of the terrain, it can be the main agent of erosion and sediment transport.
Underground circulation
As its name suggests, it refers to the circulation of water under the surface, once infiltrated.
Fusion and solidification
They are the changes in the state of the water that occur due to thermal variations. The first occurs when the temperature increases and the thaw occurs; the second occurs when the temperature of the clouds falls below 0 degrees.
In this case, the precipitation occurs in the form of snow or hail.
Can water stop being a renewable resource?
Renewable does not mean unlimited. As we have seen, water is regenerated through a cycle that repeats itself over and over again, but its availability depends on the level of demand.
Thus, as the world's population increases, the planet's need for water is greater as consumption is also greater.
Another problem that tends to get worse is the deterioration of water quality. This is due to direct or indirect contamination from domestic and industrial sources. Therefore, the amount of water suitable for human consumption is less.
Thus, water will always be a renewable resource but the question is whether the amount of available water will be enough to supply the world's population.
Climate change and its consequences - global warming is the most obvious - imply a decrease in the level of rainfall and, therefore, of moving water in the cycle.
References
- The hydrological cycle and its components. FAO Corporate Document Repository fao.org.
- Water Resources: An Integrated Approach. Edited by Joseph Holden. (2014). Routledge.
- Environmental Science For Dummies. Alecia M. Spooner. (2012).
- Summary of the Water Cycle. The USGS Water Science School at water.usgs.gov.
- The Water Cycle. Precipitation Education (NASA) nasa.gov.