Reading - Part 5

Deserts on Our Doorstep

Empty reservoirs, dried-up rivers and eroded soils could signal a permanent shift in climate for southern Europe.

When it rained in Spain earlier this year, the nation celebrated. The torrential storms broke a five- year drought, refilling many reservoirs and aquifers and bringing hope to some of Europe’s most parched regions. But the jubilation was short-lived. Far from allaying fears about long-term water shortages across the Mediterranean, it is now clear that the downpours simply reinforced the trend of a generation, in which long periods of drought are broken by intense storms.

There is now growing concern that, because of global warming, such conditions will become the norm in southern Europe. As the signatories to the Climate Change Convention meet in Geneva next week to discuss how to prevent disruptive climate change in the 21st century, climatologists are claiming that the first stages of "desertification" can already be seen in Spain, Portugal, Greece and Italy. In fact, they argue that the process has been under way for three decades.

The most detailed warning to date comes in a report completed earlier this year by a research programme called Medalus, funded by the European Commission and coordinated by John Thorne, a geographer at Kings College, London. Medalus has spent five years bringing together climate modelling, remote sensing and detailed studies of land and water at field sites to build up a picture of ecological change in the region. Drawing on the expertise of more than 40 European scientists, the report concludes that climate change is happening now, in Europe, with potentially devastating consequences for millions of people.

Mediterranean Europe has always lived on a climatic knife edge. Typically around 60 centimetres of rain falls each year, mostly in winter, often over just a few days. But in southeast Spain, for instance, average rainfall is only around 20 centimetres a year, with only 5 centimetres in a very dry year such as 1995. Of that, most evaporates; perhaps a tenth reaches rivers.

Droughts are becoming more frequent, and lasting longer. The extended drought in Spain from 1990 to 1995 was only part of a long-term trend. Thorne told a conference on Europe’s climate, organised by the European Commission in Brussels in May, that new analyses of rainfall data reveal "a turning point towards progressively lower rainfall since about 1963". At the same time, there has been "a clear increase in the number and duration of both heat waves and violent storms," he said.

Reduced rainfall will also have major implications for vegetation. Ian Woodward of the University of Sheffield says that "there will be a significant reduction in plant cover" in those areas that are already low in vegetation. A study for Medalus of three species of grass and shrub prevalent in Spain found that seed germination among all three species had completely failed in 1993 and 1994.

Vegetation loss often triggers erosion, as soil is left bare. Rainwater runs off the land quickly, rather than infiltrating soils, causing the paradox of more flooding and drier soils. In Greece and Spain, more than 40 per cent of the soil is already suffering from erosion; in Turkey the figure is 70 per cent. In parts of Spain and Italy, annual soil loss exceeds 250 tonnes per hectare.

There is much scientific debate around the world about desertification and the processes that cause it. Some scientists argue that human abuse of the land only rarely leads to its permanent loss. What few doubt is that permanent climate change will create deserts. And permanent climate change is what the highly vulnerable lands of southern Europe face today. Global warming is not just on Europe’s doorstep. It has stepped inside.