More than 32 million Spaniards, that is, 70% of the population, are already being affected by the consequences of climate change, a phenomenon that is causing a lengthening of the summers, accumulating very warm years in the last decade and causing an increase in the frequency of tropical nights.
This is evidenced by the Open Data Data Climate, a tool of the State Meteorological Agency (AEMET) of free access from the month of April, which has had information from its National Weather Data Bank and, in particular , with data from a total of 58 observatories.
According to the conclusions of this preliminary study, the average temperatures of all the seasons are increasingly higher, although the rise is seen more clearly in spring and, especially in summer, season that becomes the most affected by climate change , because it is getting longer and warmer.
In particular, the data reveal that summer is extending nine days on average per decade, which means that the current summer covers five weeks more than at the beginning of the 1980s, although warming affects all seasons of the year. In general, temperatures are warmer now between April and October, confirming that this season starts before and ends later. “It is something that we all notice and the data confirm us”, underlines one of the spokesmen of the AEMET, Rubén del Campo.
The data also reveal that surfaces with semi-arid climates are advancing in Spain, and already occupy 6% more than in the period 1961-1990, ie, about 30,000 square kilometers, a “considerable” increase, according to another spokeswoman of the AEMET, Beatriz Hervella. The most affected areas are Castilla-La Mancha, the Ebro valley and the peninsular southeast, as these are the most likely to not register rainfall.
With regard to temperatures, the study confirms a trend towards higher temperatures in Spain since 1971, both in average and maximum and minimum values, which directly affects the population in relation to the mortality rate. This result is consistent with the fact that the warmest years have been recorded mostly in the 21st century.
Of the 58 observatories analyzed, 37 registered at least five years since 2011 with average annual temperatures located within the 20% of the warmest of the reference period (2011-2018). These anomalies show that at least five of the last eight years in these observatories have been very warm, being the “most extreme case” in Barcelona, where since 2011, the average annual temperature has been between 20% of the most warm from this year, reference period.
Also, in five observatories, including Murcia or Teruel, every year except one, they have exhibited a similar behavior, while in Madrid this has been the case in five of the last eight years.
THE MOST VULNERABLE: THE MEDITERRANEAN AND THE GREAT CITIES
On the other hand, the study indicates that the surface temperature of the Mediterranean is increasing 0.34ºC per decade since the beginning of the 80s. This contribution of heat causes a thermal expansion that contributes to the increase in sea level. In fact, since 1993 the level of the Mediterranean has increased by 3.4 millimeters per year.
According to the results of the Open Climate Data, an increasingly warm Mediterranean climate affects its coastal regions by increasing the number of tropical nights, that is, those in which the minimum temperature equals or exceeds 20ºC.
In this sense, both speakers have highlighted the amplification of the effects of the phenomenon ‘island of heat’, positive thermal anomaly that takes place in the center of the cities in relation to the periphery. According to the Open Climate Data, this nocturnal thermal surcharge that raises minimum temperatures affects the comfort of citizens due to their harmful effects on health, particularly for those risk groups that live in large cities.
Both effects, therefore, point to the large cities and the Mediterranean coast as the two environments most vulnerable to climate change.
Finally, the occurrence of heat and cold waves has been studied. Although cold episodes decrease in number of days, heat waves tend to concentrate in recent years, with special emphasis on their duration. This fact is particularly relevant, as Hervella has pointed out, since there is a high correlation between maximum temperatures and mortality, since deaths increase dramatically after a certain threshold of maximum temperature.