There are 7 billion mouths to feed and in 2050 there will be 9 billion. Will there be enough for everyone? This depends on the use we make of water, as the production of daily food for one individual consumes around 2,000 and 5,000 litres of our most valuable asset on Earth. Every day, agriculture and stockbreeding, which occupy nearly 11% of the surface of the Earth, produce 23.7 million tonnes of food. Quantitatively these figures are deceptive: they would be enough to ensure the feeding of the world´s population, but the WHO (World Health Organization) denounces that nearly 800 million people suffer undernourishment.
The distribution is not equitable and there are several causes, but the most important one would be that large farming areas are becoming less productive. The lack of water and the increasing droughts, along with monoculture and the lack of training and technological resources, threaten millions of small farmers and stockbreeders who until now have been the foundation of food security in the poorest areas of the planet. The FAO (Food and Agriculture Organization of the United Nations) points out that 500 million small farms provide 80% of the food consumed in the developing world.
The surplus of the most productive areas does not reach those who have less, and it is not ethical to have, according to the WHO, 2 billion overweight and obese people in a world where there is plenty of food. Those of us who overfeed ourselves are those who waste a third of the produced food (around 1.3 billion tonnes every year). It is a waste of working hours, of arable land (1.4 million hectares of farmed land in vain), of fertilizers, of energy (3.3 million tonnes of CO2 equivalent) and, above all, of water: the food that is thrown away has needed more than 250 km3 of water; a volume that amounts to three times the volume of water of all the rivers in the Iberian Peninsula in one year. This is certainly not sustainable.
Agriculture, the main consumer of water
In 2013, the FAO estimated that 37.7 % of the surface of the Earth was destined to agriculture, and that 70% of these areas were irrigated land. It is estimated that nowadays, the amount of water needed for this purpose ranges between 2,000 and 2,600 km³per year.The water to irrigate is obtained from the freshwater resources (aquifers, rivers and lakes). These charts show the destination and evolution in time of extracted water on Earth during the last century: