«A normal summer will be as intense as the one we are experiencing»

The Búbal reservoir, in the Pyrenees of the province of Huesca, at a minimum this week. / EFE/Video: Atlas

Interview with Ruben del Campo

There is less rain, but also a different way of raining, which prolongs periods of drought, warns the AEMET meteorologist Rubén del Campo

The images seen this summer of almost dry swamps, while some towns facing water restrictions and regional governments warn of the possibility of turning off the tap in large cities, is due to the fact that all reservoirs are below 40% – with the south of Spain even thirstier. “This meteorological drought began to be noticed at the end of winter, which was a very dry season. In spring it rained a lot, March and April, but since then there have only been a few storms," ​​says Rubén del Campo, meteorologist at the State Meteorological Agency (AEMET), about this particularly arid season, with an average rainfall of 27% less (421 liters / m2) than the average since the sixties, when it began to be measured in Spain (572 liters / m2).

“We have had rains below normal for many months. To determine the meteorological drought, the hydrological year is analyzed, which is the period from October 1 to September 30 of each year, a moment that better defines the rainy cycle, which usually arrives in autumn.

–Is this drought unusual and can it be attributed to climate change?

–When we analyze the long-term rainfall, since the end of the 19th century, there is no clear trend that we can attribute to climate change in terms of whether it rains more or less. Some studies indicate that the dry periods begin to be longer in the south of the peninsula. But the results vary a lot depending on the methodology and the stations analyzed. It has also been determined that when there are episodes of torrential rains in the Mediterranean area, more water falls. What we are seeing is a different way of raining. The amount is the same, but in shorter periods and with more virulence, which is less useful.

– We then live what scientists warn: concentration of rains and prolongation of droughts.

–As a consequence of global warming, an increase in rainfall is predicted in many areas of the planet, because the atmosphere can contain more water. But in the Mediterranean region the opposite is predicted: a decrease in rainfall and a lengthening of periods of drought, and that is what is beginning to be observed. It is as if the climate of North Africa is invading the south of Spain.

–Can we talk about desertification?

Perhaps, but it is hasty to say it. The truth is that the climate of the Sahara is moving towards Europe. It is predicted that in the middle of the 21st century a normal summer will be as intense as the one we are experiencing this year, which has been one of the hottest. What is now extraordinary, will be normal. We will have to face, in 30 or 40 years, hot summers and longer periods of drought. Water will be a scarcer resource.

–How does it affect the population and natural parks?

–It has been recorded that the temperature in Spain has risen an average of 1.3 degrees Celsius. Arid climates are expanding in the country. From the sixties to the last decade, they have doubled in size. The affected areas are located in the east of Andalusia, the Ebro Basin or in Castilla-La Mancha. This translates into less availability of water for living beings because there is more evaporation.

–Before being arid, what was it?

-It was a climate in which the precipitation was above the evaporation of the water. It can be referred to as tempered.

-It says that they have doubled its extension, how much are we talking about?

–It is estimated that in the 1960s, 7% of the country's surface was arid, while in this second decade of the 21st century it has reached 14%.

–Do ecosystems adapt to these changes?

–Ecosystems have to adapt to the situation. The climates that have become arid were already close to being so, although their transformation has accelerated with rising temperatures. All this results in forest fires. Drought favors these large-scale events. It is a natural risk that this year is on the front page due to the large number of hectares that have burned. If there is more heat, there is more drought; and, therefore, favorable conditions for fires are generated.