The Desertification of Spain's Drylands
The Guadalentín Valley in Murcia. If you've ever driven to Andalucía along Spain's east coast, chances are you've passed through it. Home to the towns of Lorca and Alhama de Murcia, it's an arid corridor making its way from the sea at Guadamar de Segura to the town of Puerto Lumbreras, backed by the stark massifs of the Sierra Espuña and Carrascoy. The Guadalentín River has been described as the wildest in Europe; bone-dry at one moment, it can fill up with a violent torrente when there's a rainstorm. Most of the time, it's a rambla. In the dry months, people even park their cars in its rocky bed at Puerto Lumbreras.
Since 2000 the Guadalentín Valley is reportedly Spain's driest area. An environmental report by Coordinadora de Agricultores y Ganaderos (COAG) analyzed annual rainfall and average temperatures in different zones, basing its findings on the LANG index, a 'thermopluviometer', which works out an area's aridity by dividing its annual rainfall (mm) by its mean annual temperature (C). According to LANG there are six categories of hydric performance, ranging from 'desert' to 'superhumid'.
Whereas the Guadalentín Valley once qualified as 'super-arid', it now qualifies as 'desert'. In the last sixteen years, the area received on average 78.4 litres of rainfall per m2. To put that in context, the national average is 622 litres. According to COAG, this means the valley is 'like Arizona or the Sahara Desert', and the agricultural productivity of the area could become endangered.
What is happening in Guadalentín is not unique. It's symptomatic of a wider pattern - called 'desertification' - affecting many parts of the peninsula. 'Desertification' is the degradation of dryland ecosystems by climate change and damaging human activities.
Scientist Jaime Martínez Valderrama, who works for the Almería-based Estación Experimental de Zonas Aridas, which has been developing a simulator-map of current trends, claims that over 20% of Spanish territory has been degraded to the point of desertification. This means that a fifth of the land mass has lost part or all of its potential for productivity. Two-thirds of Spanish terrain falls into the 'arid', 'semi-arid' or 'dry sub-humid' categories, and is therefore vulnerable to desertification. Murcia, Canarias and Comunitat Valenciana are the regions chiefly at risk, followed by Castilla La Mancha, Catalonia, Baleares, Madrid and Andalucía.
Dryland ecosystems cover nearly a half of the globe, including about 24% of Europe. Roughly a third of the planet's human populace lives in one. These ecosystems, defined by low rainfall combined with high levels of evaporation, are particularly vulnerable to the threat of climate change. Reduced precipitation in such an ecosystem can cause a failure in the production of crops, timber and other materials essential for human survival.
Degradation over a sustained period means the ecosystem loses the ability to regenerate itself, resulting in the permanent erosion of topsoil, earth and groundwater reserves. In poverty-affected areas, human populations are forced to move on from land which cannot sustain them towards more fertile areas, where the increased pressure on over-worked land can result in further unsustainable agricultural practices and degradation.
A chain effect. So, surely these areas need special protection or prevention measures?
Generally, dryland ecosystems are better suited to nomadic grazing and herding practices, as opposed to sedentary cultivation. Over the last century Spanish practice has shifted strongly towards the latter. Encouraged by subsidiaries from the PAC (Política Agrícola Común - an organ of the EU which has been establishing agrarian practice all over Europe since its inception in 1962), huge tracts of southern Spain have been turned over to a blanket cultivation of olivos and almendros. This has stunted biodiversity - an essential ingredient in a healthy ecosystem.
Forest fires, misuse of water resources and chemical fertilizers are other factors which contribute to desertification. Then there are the invernaderos, a feature of both Almerían and Murcian landscapes. These huge, sprawling greenhouses cover the slopes of the mountains, requiring immense movements of earth similar to those in a quarry, which has a debilitating erosional effect on the landscape. In 1996 Spain was one of 191 nations to sign an accord with the UN agreeing to combat desertification, and in 2008 the Spanish Ministerio de Agricultura, Alimentación y Medio Ambiente hatched its own Programa de Acción Nacional Contra La Desertificación, prioritizing the 'prevention of degradation of lands' as well as 'the recuperation of lands already affected'. Until now there have been no plans to combat the ravaging consequences of the invernaderos as part of the Programa de Acción Nacional Para Combatir La Desertificación.
Another contributing factor to the current problem with land degradation was the early 1990s boom in 'especulación urbanistica', which led to the widespread conversion of arable land and fluvial vallies into urbanizaciones, carreteras and poligonos industriales. During this period, Spain held the dubious title of not only being the European nation with the lowest proportion of high value arable land, but the one with the highest rate of urbanizing such land.
The time has come, it seems, for better land use and management practises. On June 17, the United Nations celebrates its 2016 World Day to Combat Desertification. You can read about the measures it promotes at http://www.unccd.int/en/Pages/default.aspx
With climate change and increased temperatures set to exacerbate current problems, without a sensible, conservational approach to farming systems, the degradation of the Guadalentín Valley could easily extend to other areas.