school energy&environment

Water consumption

Humans are particularly concerned about potable water, more and more insufficient in relation to the increase of the world population and as effect of pollution. Today are in function, especially along dry coastal regions, plants making seawater drinkable to compensate for shortage of potable water among continents.
Water in all its forms is important also because it’s an essential part of Earth’s landscape, infact, it contributes predominantly to the shaping of the world’s surface and determines the typical climate of the region.
Variability of climate and hydrogeological conditions makes water availability extremely different from one region to another. We can talk about water scarcity when annual per capita amount of available water drops below 500 cubic metres. Even those countries with great availability of fresh water are exposed to the risk of having to face water scarcity. Water insufficiency, infact, is a relative concept as it can refer to the total lack of water or to the difficulty of acceding to safe water reserves. Water resources are more and more exploited on all continents by the growing request of irrigation interventions for agricultural purposes, for urbanization activities and for industrial use. Economic development and urban growth often cause damages to water flows due to the increase of pollution. This reduces the amount of good quality water available for primary uses as drinking, eating and personal hygiene.
In the past century world consumption of fresh water has had almost a tenfold increase and about 70% of water consumed on Earth is employed for agricultural use. This percentage is lowering as the consumption for industrial use (22%) and domestic use (8%) is increasing. In less developed regions the percentage of water destined for agricultural use proves to be greater while in most developed regions the percentage of water destined for industrial and domestic uses is higher.
The more we move towards countries with a lower income, the more the percentage of water destined to crops increases, up to an average of 82%. Countries with a high income, instead, use less water for agriculture (an average of 30%), but they use more water in the industrial sector and for domestic use, an average of 59% and 11%.
If we analyse average per capita consumption, we discover that this varies greatly in many countries: according to the United Nations, an American in the United States uses 575 litres of water a day, an Italian uses 385 litres, while an Indian and a Chinese use 135 litres and 85 litres respectively. An explanation given considers that a high standard of living implies high water consumption while it’s not so true the opposite: infact, in less developed regions, agriculture absorbs the greatest part of available water but, due to the inefficiency of irrigation systems, about 60% is lost. Always through inadequate distribution is lost 36% of available water for industrial and urban uses. In addition to this, there are drought problems, climate changes, deforestation and pollution of groundwater.