Upward trend of temperatures in the Iberian Peninsula

The curious thing is the rise in minimum temperatures. Tablelands are the most representative area from a climatic point of view; if we take them as a reference, according to Staudt´s systematized data, Spanish minimum temperatures have risen about a degree from the first thirty years of the XX century to the last three decades.

The rise in maximum temperatures is lower and more irregular than that of the minimums, which have risen in all the regions of the national climate map, especially in the Valleys of the River Ebro and Guadalquivir, a degree and a half. Minimums of cities like Sevilla have risen 2 centigrade degrees in the last years. If we correct the so-called urban effect, typical of big and medium cities, the rise is of 1.6 degrees. In the Mediterranean and Cantabrian coast, warming is lower.

According to experts´ data, the average temperature of the planet raised considerably in the last century. Specifically, from 1880 to 2000, an average of 0.7 centigrade degrees. “The trend found in the Iberian Peninsula agrees with the global one (at a planetary level) and can be observed above all in the last thirty years”, points out María Jesús Esteban Parra, director of the thesis together with Yolanda Castro Díez. To come to this conclusion, the scientists of the research group Atmosphere Physics of the UGR (Universidad de Granada [http://www.ugr.es]) have systematized the quality of the data of the Natioanl Institute of Meteorology, since the 1970s.

After an introduction to the climatic variability of the Peninsula, forty-five Spanish original time series have been catalogued monthly averaged. It is not an easy job. “Sometimes, weather stations which take temperatures move or measures get affected by different non-meteorological factors, like urbanization. If these changes are not taken into account and corrected, data can not be compared to the previous ones”, explains doctor Staudt.

Therefore, “this work is essential because if we do not homogenize the data, we can not come to any conclusion about climate change”, concludes Professor Castro. To go deeply into climatology, they do research into variables like sunny hours, cloudiness and their connection with temperatures. The typical global difference in the behaviour of maximum and minimum temperatures has disappeared since 1970. Thus, in the last thirty years, both groups clearly rise whereas cloudiness decreases, which may mean an increase of the subtropical nature of the peninsular climate.