The heat waves and forest fires that swept across the Mediterranean this summer taught Europeans serious lessons about the dangers of climate change. But many experts also worry about a long-term problem: desertification.
This is a process that is usually irreversible, and it is a growing problem in Europe-especially in Spain, where approximately one-fifth of the country has been affected.
“Desertification, together with climate change, biodiversity loss and pollution, is one of the world’s four major environmental problems,” said Elias Symeonakis, an expert on the subject at Manchester Metropolitan University. “We rely on areas that are degrading… for our food and our population. Once they degenerate, there is nothing you can do.”
Desertification can be reminiscent of the romantic image of sand dunes. In fact, the process is more mediocre. It refers to the degradation of land in arid regions, making it unproductive and barren.
The main reason is usually human activities, such as over-farming and over-irrigation, which erode the soil and drain the aquifer. The scale of this problem is daunting in Spain, where agriculture has been steadily industrialized, and three-quarters of the land is generally arid or semi-arid.
“Spain is the EU country facing the greatest risk of desertification,” Deputy Prime Minister and Environment Minister Teresa Ribera told the Financial Times. She added that the government plans to formulate a national strategy this fall for the first time in 13 years.
The regions of southeastern and eastern Spain are the hardest-hit areas in Europe, partly because they are separated by mountains from the milder northern regions. But desertification also occurs in Italy and Greece. The crises in North Africa, the Palestinian territories and Mozambique are more serious.In the United States, excessive water use, coupled with the recent drought, is steadily increasing Dry up the western United States.
Prospects for world temperature Rise 1.5C As this month’s IPCC climate change report emphasized, the pre-industrial levels by 2040 will make the situation worse. Increasingly common forest fires can cause severe damage to the fertility of the topsoil. The hot summer will also turn the soil into dust, and extreme rain will wash it away.
In Spain, some 20% The land has been desertified, mainly due to historical reasons, such as destructive mining and over-farming after the change in the use of land acquired from the Catholic Church in the 18th and 19th centuries. In these areas, fertile land can no longer produce a large number of crops for humans or animals, although some vegetation may continue to exist.
Satellite images show that another 1% of Spanish territory is severely degraded due to intensive agricultural activities, although larger areas are also indirectly affected.
“It’s like a black hole,” said Gabriel del Barrio, a researcher at the Almeria State Arid Zone Experimental Station, which is one of the most affected areas. “This 1% will endanger the surrounding countryside within a few kilometers… exhaust water and cause other damage.”
He added that, contrary to popular misunderstandings, desertification does not mean the development of deserts. “For example, the Sahara Desert is a very mature system,” he said. “On the contrary, it is about the unsustainable overuse of natural resources, which are replenishing very slowly, if at all.”
Compared with any primitive Sahara Desert, desertified lands such as the Gador Mountains in Almeria have very thin soil and are covered by vegetation. At the same time, the rapidly deserted areas of eastern Spain may appear lush due to the expropriation of a wider area of water.
Like many other experts, Del Barrio connects desertification with land use changes, agricultural industrialization and intensive irrigation.These changes help increase Spain’s agricultural income Nearly 50% In the decade to 2020.But the agricultural industry also uses Almost seven times As much water as all Spanish households.
This use of the earth’s resources will cause a heavy price.about Quarter According to the European Union, the country’s aquifers have been over-exploited. Modeling by Jaime Martínez Valderrama of the University of Alicante suggests that the soil for wheat and sunflower crops in Córdoba may be depleted within 60 years.
The olive industry is another example. Since Roman times, Spain has been famous for exporting olive oil. However, although traditionally this crop requires little irrigation, it is now grown in high-density orchards where the plants resemble shrubs rather than trees.
These can be harvested by machines, and productivity has greatly improved from the ancient farm workers’ cutting trees to the tradition of raining olives. But this intensive agriculture also has greater water demand.
In the provinces of Jaen and Granada, the olive industry is the main water user. In Andalusia, agriculture accounts for nearly 80% of the region’s total water use.
Industry groups say that more efficient irrigation systems will enable agriculture to reduce water use this century. Even so, in the past decade, the industry’s consumption has climbed again. Experts worry that current trends are unsustainable.
“This is an old saying:’The more water, the sweeter the fruit,'” said Vicente Andre Perez, a senior researcher on desertification at the Spanish National Research Council. “But we cannot increase agricultural profits indefinitely. Everything has a limit, and in this case, if we reach the limit, we won’t be able to go back.”