Water, blue gold

2000/06/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Ingurumena

Biologists have concluded that tropical Africa has a high risk of severe droughts in the next 50 years after performing paleoclimatic studies in Kenya's Naivasha Lagoon and measuring rainfall in the region. Although it is not the first time, due to the strong increase in population pressure, the consequences could be more serious, since in the fourth century the population of the region has doubled. But Africa is not the only focus of conflict; according to the United Nations, the political and military conflicts caused by water are the XXI. They could become a major problem of the 20th century.

One of the most significant points of conflict is the Middle East, the Jordan basin. Lebanon, Syria, Jordan, Israel and the Palestinian territories do not coincide in the distribution of river water and water is a source of conflict between Jews and Palestinians every day, as the depth of the wells of both is different from the prices to be paid. This is a historical conflict, as the six-day 1967 war also began with water. But politically cheaper countries also have conflicts. Canada and the United States have frequent clashes over the use and pollution of the Great Lakes and the rivers that separate them. In 1995, for example, the Canadian province of British Columbia banned the sale of water.

However, the conflicts caused by water are not new; the civilization that left without future the scarcity of water has already seen them before. The drought, which began 4,200 years ago and lasted for three centuries, caused the destruction of the empire of Akadi, one of the first great empires of human history, which was born in Mesopotamia. The decline of South American cultures prior to the Incas or the Saba kingdom of Yemen was also driven by water shortages. But droughts are not the only dangers. The irrigation of the lands has also caused problems such as the sweeping of lands, the exhaustion of the water table and, above all, the salinization of the soil.

These problems played an important role in the loss of diverse Mesopotamian cultures and, apparently, many times have failed civilizations closely linked to irrigation.

In general, fresh water is not so scarce. There are 1,800 m3 of fresh water per person per year in the world, poorly distributed, but an Egyptian has 30 m3 of water per year and an Icelandic 708,000 m3. "Water stress" on countries can soon become a serious problem for about 30 states with less than 1,000 m3 of water (per person per year). It must be said that below that amount of water human health cannot be guaranteed. On the other hand, demographic pressure leads us to the exploitation of poor lands, with a huge increase in the need for irrigation, and on the other hand, per capita consumption of water grows rapidly, very quickly.

A fifth of the world's population does not have access to drinking water and half lack basic health infrastructure. Every year, 3.4 million people die from diseases caused by the consumption of non-potable water, of which 2.2 million are low and 1.1 million malaria. In general, water scarcity causes 80% of Third World diseases. And surely the situation will get worse: in a century the world population has tripled, but water consumption has multiplied by six.

Increased consumption and demand has resulted in the multiplication of water access difficulties in different parts of the world. Water is exploited without respecting the speed of renewal of the hydrological cycle, so in addition to reducing the flow of many rivers, lakes are also drying up. On the other hand, due to the excess pumping, the water levels of the aquifers have decreased considerably in recent years, having been lost in some cases tens of meters. Due to the lower water availability of aquifers, the rivers supplied by them also receive a lower flow in the dry season, especially in the dry season, and some have completely disappeared. The rapid drainage of the aquifers makes this situation especially serious in the reserves near the sea (since saltwater will occupy semi-defuged aquifers) and in the "fossil" water, that is, in the aquifers with unregenerated water. In India, for example, hydrologists have announced that water is being pumped through the subsoil up to twice the speed of the renewal cycle and that this depletion rate will cause a 25% decrease in harvest. Very worrying values, since India is a country with 18 million new inhabitants each year.

But it is not the most serious problem. Most of the water we extract from the surface or subsoil is used as if we had as many as we wanted or without efficiency.

60% of water destined for irrigation channels is lost by evaporation or by discharges. In addition, 20% of the land irrigated in the world is saturated and salted by these spills, which considerably reduces soil fertility. Water is not lost only in agriculture. Public water distribution networks also often suffer significant leaks, especially when they are made up of old poorly preserved pipes. 25% losses are common in industrialized countries and 50% losses are not exceptional either. Water is not only deficient, it is used incorrectly, and many of them are lost on the way from source to consumption zone.

And not only that. The quality of this scarce misused water is not good enough either. Untreated wastewater, industrial spills, leaks from oil transport pipelines, landfills, agricultural pesticide and fertilizers contaminate water, although the magnitude of pollution is not the same in each region.

Water is scarce and of worse quality. The distance between the volume of water available and the volume of water we use is getting smaller. The use of water resources will increase by 10-12% until 2025 of the decade, while water resources will already be reduced.