Water is essential. Soils are infertile without it. Life cannot exist without it., as it is the environment in which the chemistry of living organisms unfolds. Water is also found on the earth and in the atmosphere, but it is unevenly distributed on the surface of the planet. In one region, there are long treks through the desert for a few litres; in another, an excess of baths, showers and waterfalls.

In the wealthy nations, water is seen as a cheap and inexhaustible resource. Intensive watering and the massive application of fertilizers contribute to the growth of the plant biomass of high-yield crops; as a result, in the regions where water is plentiful, it becomes polluted by the runoff of contaminants from the soil. In some regions, water causes flooding, inundation and destruction, and carries disease and death from the parasites that it harbours. Elsewhere, the lack of water is a cruel hardship.

So the relationship between humans and water has always been, and will continue to be, ambiguous. To make it harmonious, we will need to strike a balance that is difficult to define. Taking stock of the situation is becoming a priority across the globe.