WATER SCARCITY: CAUSES, CONSEQUENCES, SOLUTIONS AND EXAMPLES - BIOLOGY - 2025

Water scarcity is the lack of this liquid in terms of its availability for drinking, preparing food and personal hygiene. For these uses, the water must meet minimum quality parameters and is called drinking water.

The term also encompasses the deficit of water for agricultural and industrial activities. It is pointed out that one of the main crises facing humanity in the immediate future is water scarcity.

Abandoned boat in a place where there used to be water (Aral, Kazakhstan). Taken from Staecker

The causes that determine the scarcity of water are both natural and anthropic, that is, caused by humans. Among the former are the uneven distribution of water on Earth and high evapotranspiration rates in some regions.

By human action, phenomena such as global warming are generated that cause increased temperatures and alter precipitation patterns.

Additionally, human beings demand more and more water as the population grows, while polluting the existing water. On the other hand, the scarcity of water in some cases is not related to the non-existence of the resource, but to its accessibility.

Causes of water scarcity

Source: UNESCO

Water scarcity is caused by both natural conditions and human action, bringing together a complex series of causes.

- Natural causes

Uneven natural distribution of fresh water and its availability

Water is an abundant resource on Earth, taking into account that 70% of its surface is covered by this element. However, of all the water on the planet only 3.5% is fresh water and it is not evenly distributed, nor fully available for consumption.

Almost 70% of fresh water is frozen in glaciers and therefore not directly available. In short, it is estimated that the drinking water available on Earth is no more than 2.5% of total water.

High evapotranspiration rates and low rainfall

In arid and semi-arid zones, high temperatures imply high evaporation rates, which together with low rainfall determine the water deficit.

- Anthropic causes

The human being is the species that has the greatest impact on the environment and in the case of water scarcity its effect is direct. Humanity is the cause of ecological imbalances that affect the water cycle and cause scarcity for its own consumption.

Global warming

The unusual increase in global temperature due to the action of humans implies extreme droughts in some regions of the planet and in general an increase in the evapotranspiration rate. This directly affects the loss of surface and groundwater sources.

Contamination of water sources

Another factor that causes drinking water shortages is the contamination of surface and groundwater sources. If the quality of drinking water is considered, contamination problems bring the percentage available to critical levels of only 0.025%.

Population increase and water extraction

The human population grows exponentially and so does the demand for water; between 1961 and 2014 the extraction of water multiplied 2.5 times.

Crops

In general terms, agriculture accounts for 70% of all the water consumed by humans. But additionally, some crops present high rates of water extraction from the soil due to the evapotranspiration demand.

Eucalyptus plantation (Eucalyptus sp.). Source: Shyamal

For example, forest plantations in general, and especially those of eucalyptus, are highly demanding on water. These species deplete aquifers because they can evapotranspire up to 76% of the water received by rainfall.

Poor maintenance of water reserves

The deficient maintenance of water reserves (dams, lakes, ponds), can increase the evapotranspiration rate and consequent loss of water. Especially the proliferation of aquatic weeds has a great incidence in increasing the rate of water loss by evapotranspiration.

Poor delivery service

In many parts of the world, especially in less developed countries, the water distribution system is causing scarcity. On the one hand, inadequate distribution systems have high water losses through seepage.

Consequences

Public health

Water is essential for life, so its lack implies serious health problems. First of all, a deficient consumption of water leads to dehydration problems and even death.

On the other hand, the scarcity of water encourages the consumption of water that is not potable or with poor drinking conditions. This in turn implies the risk of contracting gastrointestinal diseases or of poisoning by water contaminated with heavy metals or other substances.

Person carrying water in desert area. Source: MrGauravBhosle

The main cause of infant death worldwide is gastrointestinal diseases due to the consumption of contaminated water. Diseases such as cholera and typhus are present with great force in regions with problems of access to drinking water.

Food production

The scarcity of water implies a decrease in the production of food of both plant and animal origin. This in a world with a growing demand for food is a problem with serious consequences.

Human development

Water scarcity negatively impacts human development indices, not only directly due to its effect on health. Communities that do not have easy access to water must devote many potentially useful hours to work searching for this resource.

In the same way, the hygiene of people, the home and animal and plant production are affected. Industrial activities are also affected by the lack of water, which is required for many of the processes.

Desertification

Desertification Source: Jeanajean

Water scarcity is the cause of desertification, especially in arid and semi-arid areas. For this reason, according to the United Nations Convention to Combat Desertification, by 2030 24 to 700 million people will migrate for this reason.

Solutions

Solving the problem of water scarcity encompasses a series of interrelated measures that are part of a sustainable approach to human development.

- Water conservation

The first action is to raise awareness regarding the existence of the problem, its severity, causes, consequences and possible solutions. Conservation awareness of water not only contributes to its conservation, it contributes to pressure for other measures to be taken.

Rational use

Citizens can make a fundamental contribution by making rational use of the water resource, using only the amount strictly necessary. Open taps, leaky pipes, use of water polluting products, are all elements that contribute to aggravating the water shortage.

Green roofs

Promoting the establishment of properly planned green roofs reduces water loss due to runoff, as it favors infiltration. This allows the recharge of the underground aquifers that in turn maintain the baseline of the rivers.

Reduced evapotranspiration

The presence of floating aquatic weeds in dams, lakes and other bodies of water increase the loss of water through evapotranspiration. Therefore, eradication of such plants from drinking water reservoirs must be ensured.

- Control of population growth

It is necessary to reduce the growth rate of water demand and therefore it is necessary to decrease the population growth rate. In the long term, the available drinking water will not be enough to satisfy the demand of human beings and therefore a strategy to control population growth is essential.

- Reduction of global warming

International commitments to reduce the emission of greenhouse gases seek to reduce the rate of increase in global temperature.

- Prevention of water pollution

One factor that promotes the shortage of drinking water is the contamination of fresh water sources. The contamination of rivers, lakes and underground aquifers reduces the amount of water available for human consumption, agriculture and livestock.

- Sewage treatment

Another way to avoid the scarcity of this resource is to treat, reuse and recycle the water used for consumption. Wastewater must be treated before being reintegrated into the environment and gray water can be reused in toilet drainage or irrigation.

- More efficient industrial and agricultural systems

The efficient use of water in agriculture and industry contributes to its saving, which increases the fraction available for human consumption.

Irrigation systems

Irrigation is the activity that consumes the most water in agriculture, so the use of inefficient systems represents a problem. Irrigation systems such as the drip system are much more efficient than sprinkler or gravity systems.

- Drinking water distribution systems

As has been pointed out, there may be enough water and yet there may be a shortage for a certain segment of the population. This occurs when the resource does not reach the population that requires it due to lack of an adequate distribution system.

- New sources of drinking water

An alternative to the scarcity of water is to increase its sources and in this sense there are basically two options: sea water and glaciers.

Desalination

Removing salts from seawater and obtaining potable water is a growing alternative in countries with severe water shortages. In fact there are 18,000 desalination plants operating worldwide, the largest of which is in Saudi Arabia.

Desalination plant. Source: Arch. Michael Jacobson, Israel, However, for now the water obtained by this means only covers between 1 and 3% of world demand. This is because desalination processes require large amounts of energy.

Glacier water

Since 70% of fresh water is in the form of ice in glaciers, some see these as a source of drinking water. In fact, there are companies that produce bottled water that market glacier water as a luxury product.

However, this may have an ecological impact, taking into account the threatened state of the world's glaciers. In addition, it can have negative effects on a large part of the hydrographic basins that feed on high mountain glaciers.

Water shortage in the world

Water shortage in the world. Source: Axelsaffran

The scarcity of water in the world is a growing problem due to the decrease of the resource and the increase in demand as the population grows.

Water withdrawal rate and water stress

The scarcity of water in a given region is determined by the relationship between the available water and the extraction rate. This determines the level of water stress and varies depending on the uneven distribution of water and the human population on Earth.

There are sparsely populated very humid areas in the world, while other arid and semi-arid areas lack the vital liquid and are home to large populations. For example, in the region of Mexico and Central America there are almost 200 million inhabitants, but it only has 1.5% of fresh water.

For its part, South America has 31.8% of the fresh water reserves for 422 million and Asia with almost 4.5 billion inhabitants only have 28.9% of the reserves.

Global scarcity

About 2.5 billion people live in regions with a high water deficit, according to the World Resources Institute. On the other hand, even with large water reserves, there may be a shortage, due to poor distribution or the economic and technical impossibility of using it.

Person looking for water in a well. Source: Bob Metcalf

In addition, the shortage increases if one speaks of quality drinking water, since in many cases the water consumed is very deficient. In countries such as Venezuela and Peru with significant freshwater reserves, they face serious shortage problems.

According to the World Resources Institute report, by 2030 the global demand for drinking water will exceed supply by 2,680 km3.

Countries according to their stress due to water scarcity

Currently 17 countries in the world have extreme levels of water scarcity, the majority in Northeast Africa, the Middle East, Asia and Hindustan. Then 27 countries face high levels of water stress, among which are Chile, Mexico and Spain.

For their part, Peru, Venezuela and Cuba present medium levels of water stress, and Argentina is located at a low to medium level.

Water shortage in Mexico

Source: gov.mx

Mexico is a country with serious water scarcity problems, first of all because more than 60% of its territory is arid or semi-arid. According to the WRI report of the 32 states in which the Mexican territory is divided, 15 face extreme water shortages.

On the other hand, unequal distribution exacerbates the problem, with centers of high population concentration, such as the Valley of Mexico, especially Mexico City. In Mexico, about 12 million inhabitants do not have adequate access to drinking water

Source contamination

Additionally, the supply of drinking water is hampered by the increasing contamination of its sources. In fact, 70% of the rivers present some level of contamination, since less than 25% of the sewage is treated.

Water shortage in Colombia

Source: gov.co

Colombia has large river basins with extensive rain forests, but it faces problems of water scarcity, due to the contamination of rivers and underground sources. Likewise, there is a depletion of sources due to the growing demand of a poorly distributed population in the territory.

The water contamination

In Colombia, 67 m3 / s of sewage is discharged to natural channels, of which only 8% is adequately treated. The Bogotá river that runs through the capital is one of the most polluted in the world due to the discharge of sewage.

Water shortage in Peru

Source: gov.pe

Peru is in the tropical zone, counting on regions of high precipitations and extensive humid forests. However, it faces problems of water scarcity, especially in its arid coastal zone.

Source: gov.pe

Inequality in consumption

According to the National Superintendency of Sanitation Services (Sunass), about 25% of the population has problems with the supply of drinking water. In addition, there is a marked inequality in supply and consumption, and areas such as San Isidro consume more than 400 liters / person / day while in Lurigancho and Chosica only 15 liters / person / day.

Water scarcity on the banks of a river

In the Piura River region, in the Tambogrande district, there is a common contradiction in many parts of the world. There is a mighty river with polluted waters and therefore the inhabitants must consume drinking water supplied by cisterns brought from other places.

Water shortage in Venezuela

Venezuela is the second country with the most water reserves per capita in the world, however it faces drinking water supply problems, especially in large cities and in arid and semi-arid areas in the north of the country.

10 years ago 90% of the population had access to drinking water, today 70% suffers from a shortage of quality drinking water. In this case, due to the insufficiency and lack of maintenance of the processing and distribution system.

Hauling water

In large cities of Venezuela, such as Maracay, the capital of the Aragua state, the scenes of people carrying drums of drinking water are daily. Those with low resources in particular travel long distances daily to fetch water from public fountains.

Unequal distribution of water and population

The problem of water scarcity in Venezuela is aggravated due to the inversely proportional relationship between population and water. In this country most of the population is on the northern coastal axis, where the resource is scarcer than in the south with a low population density.

Water shortage in Argentina

According to the Technical Advisory Committee of South America in Argentina 18% of the urban population lacks access to drinking water service. In rural areas it covers about 97% of the population and in the country 8 million people without access to drinking water.

Most problematic areas

More than 60% of the Argentine territory is arid or semi-arid and due to the scarcity of the resource itself as well as deficiencies in its distribution, some regions suffer serious problems of water scarcity. For example, in Santiago del Estero where about 40% of the population does not have access to this resource properly.

As in other parts of the world, in Argentina there is also a differential consumption of drinking water. In some cases it is scarce, while in others, such as Buenos Aires, it is wasted with a consumption 3 times higher than the national average.

References

1. Cisneros BJ, ML Torregrosa-Armentia and L Arboites-Aguilar (2010). The water in Mexico. Channels and channels. Mexican Academy of Sciences. National Water Commission (CONAGUAS).
2. Espinoza, A. (2017). Water quality in Peru. Challenges and contributions for sustainable wastewater management.
3. FAO (2011). The state of the world's land and water resources for food and agriculture. The management of systems at risk. Food and Agriculture Organization of the United Nations.
4. FAO (2013). Coping with water scarcity. A framework for action for agriculture and food security. Report on water issues. Food and Agriculture Organization of the United Nations.
5. FEA (2006). Water in Mexico: what we all need to know. Fund for Communication and Environmental Education, AC
6. Martinez. Z. (2011). Situation of water resources in Venezuela. AveAqua.
7. Strong, C., Kuzma, S., Vionnet, S. and Reig, P. (2020). Achieving abundance: understanding the cost of a sustainable water future. Working paper. World Resources Institute.
8. WWAP (2016). United Nations Report on the Development of Water Resources in the World 2016: Water and Employment. UNESCO. World Program for the Assessment of Water Resources.