Why is water becoming scarcer and scarcer?

In recent years, there have been several severe droughts in southern Europe. In Spain and Portugal the level of the reservoirs fell dramatically, and in Italy, in 2022, the river Po experienced its worst drought in 70 years. Temperatures above 40 degrees speed up evaporation, so the soil dries out faster and faster. Droughts are not only a European problem: East Africa, the Middle East and large parts of India are also affected.

The largest consumer of fresh water in the world is agriculture. According to the Food and Agriculture Organization, it uses about 70 per cent of the water that people take from rivers, lakes and groundwater. Particularly large amounts of water are used by crops such as rice, cotton and avocados, which are often grown precisely in dry regions. In southern Spain, for example, huge areas of greenhouses are irrigated with water from wells, many of which are illegal.

When there is too little rain, farmers increasingly use groundwater. But underground reserves renew themselves very slowly, sometimes over centuries. Satellite measurements show that the groundwater level is falling in many regions, from India to California. In some places, such as in Mexico City, the ground is literally sinking because the water beneath it has been used up.

Many countries therefore rely on desalination, that is on obtaining drinking water from the sea. Saudi Arabia, Israel and the United Arab Emirates already obtain a large part of their drinking water in this way. However, the plants use a lot of energy and produce concentrated brine, which can harm marine organisms when it is released into the sea.

Water shortages can also cause political tensions, especially when several states use the same river. Ethiopia built a huge dam on the Nile, and Egypt, which depends almost entirely on this river, fears that it will get less water. Similar disputes also exist over the rivers Tigris and Euphrates, as well as over the Indus. Experts warn that climate change could intensify such conflicts if states do not cooperate.

But every household can also contribute to saving water. Anyone who showers briefly instead of taking a bath, fixes dripping taps and runs the washing machine only when it is full saves many litres every day. Even more important is the hidden water in the food and clothes that we buy. For the production of one kilogram of beef, for example, thousands of litres of water are needed. Less meat and less wasted food also mean less water used.