More Sunshine in Spain Not Always Good News

By Paul Brown, Climate News NetworkThis report first appeared at Climate News Network.

LONDON — The sun is getting more powerful in Spain, increasing the threat of desertification but providing more energy for the country’s growing solar industry – the largest in Europe.

According to a study the University of Girona and the Federal Institute of Technology (ETH) in Zurich solar radiation in Spain has increased by 2.3% every decade since the 1980s.

This is mainly due to the decrease in clouds, which has increased the direct sunlight. The largest increase was in the summer and autumn, but the sun shone more in the winter and spring as well.

Solar radiation is measured both as direct sunlight and diffuse light via clouds, atmospheric gases and aerosols. What was striking was the decrease in the diffuse component of sunlight according to the research published in the magazine ‘Global and Planetary Change’.

Clouds decrease

One of the authors, Arturo Sánchez-Lorenzo, currently a postdoctoral researcher at the University of Girona, said the amount of sunlight reaching the Spanish land surface had increased in every decade since 1980.

“Only in 1991 and 1992 did diffuse radiation rise, and this was due to the ashes from Mount Pinatubo (volcanic eruption in the Philippines).

“The explanation (of the increase) lies in the fact that in Spain the amount of cloud has decreased markedly since the 1980s – as we have ascertained through other studies – and the tropospheric aerosol load may also have decreased,” said Sánchez Lorenzo.

“It seems to be very simple: fewer clouds result in higher solar radiation on the surface.”

Skin cancer

According to the scientists, this increase may also go hand in hand with more ultraviolet rays, an excess of which presents a health risk, potentially leading to skin cancer.

The increase in global solar radiation is a phenomenon that has been observed in other parts of the world for almost 30 years, especially in developed countries, and it has been named “global brightening”.

The fall in the diffuse component has also been observed in Central European and Eastern countries. The team behind the study has not yet analysed the solar radiation data for 2011-2013 provided by the Spanish State Meteorological Agency, but the data from other European weather stations suggests that this brightening is still on the rise.

“Studies such as these may be of interest to the solar energy industry, especially in countries like Spain, where not only do we already have a lot of direct solar radiation but now we are getting even more,” said another of the authors, Josep Calbó, who is a professor at the University of Girona.

Deserts

Until the recent recession began to bite Spain was in the middle of a building boom for all types of solar energy capture. Since 2010 Spain has been the world leader in concentrated solar power, a method of directing the sun’s rays with mirrors to boil water or oil to drive turbines and generate electricity. By the end of 2012 more than 2,000 megawatts of concentrated solar power had been installed, the equivalent of two large conventional power stations.

Although the rate of increase has slowed solar power is expected to contribute an increasingly large share of the country’s electricity needs over coming decades as large areas are now too dry for agriculture.

On the downside there is serious concern about the lack of rainfall and the increasing risk of desertification in the south of the country. The increase in sunshine is in line with scientific predictions for the northern Mediterranean coast and Italy, France and Greece are all threatened with desert conditions if the trend continues.

All four countries are members of the United Nations Convention to Combat Desertification and are taking measures like planting forests to try and prevent the Sahara Desert crossing the Mediterranean to Europe as is predicted by long term climate models.