The temperature values observed in the Pyrenees area over the last four years (2016-2019) confirm both the clear trend towards a rise in temperature recorded over the last 60 years and the future scenarios, with a thermal increase that is perhaps more in line with the scenarios of a greater increase than with those of a more moderate temperature increase (although to be sure of this fact, its evolution over the next few years must be analysed).
The climate of the Pyrenees has undergone significant change over the last hundred years, with a progressive rise in temperature, exceeding the general warming of the planet, variations in the precipitation regime and an increase in the frequency of extreme events, which are reflected in the sharp retreat of ice masses and glaciers, modifications in snow cover and changes in ecosystems. In this context, and within the framework of the OPCC, the CLIMPY project has generated a broad database of meteorological data to ascertain recent climate trends and make future projections based on the new IPCC AR5 scenarios. Information from 1163 observatories has been used, which optimally cover a large part of the territory, with the exception of the highest peaks, where the number of measurements is very low.
The increase in temperature is one of the most visible signs of the behaviour of the climate in the Pyrenees in recent decades. In the period 1959-2015 the average annual value shows a rate of ascent of +0.24 oC per decade. This increase is general throughout the whole of the mountain range, with few differences between the northern and southern slopes. The maximum temperature increases at a slightly higher rate of +0.28 oC/dec, and the minimum temperature at a rate of +0.19 oC/dec.
Seasonally, spring and summer are the times of the year that register the most marked increase, and in general the rate of thermal increase is also more evident in the maximum temperatures than in the minimum ones. In autumn the rise is more moderate and it becomes even milder in winter. From a spatial point of view the geographical distribution of the trends is fairly homogeneous, although the degree of statistical significance is not always high to be reliable. The warming observed is in line with the global diagnosis made by the Intergovernmental Panel on Climate Change and coincides with the results of the studies carried out in the Pyrenees, but always with nuances depending on the geographical area and the period studied. The more recent this period is, the more accentuated the increase and vice versa.
The trends indicated will continue during this century, with different intensities, as indicated by the climate models. The average annual and seasonal maximum daily temperature will increase under the three scenarios analyzed (CPR8.5, CPR6.0 and CPR4.5). This increase will be more pronounced in the most emitting scenario (RCP8.5) and by the end of the century, where values between 4.0 ºC and 6.3 ºC could be reached with respect to the values of the 1986-2005 period. At the minimum temperature the range would be between 3.2 ºC and 4.9 ºC. By seasons, the expected increase is greater for the summer. No significant changes in precipitation are projected; instead, it is observed that the uncertainty associated with the models is greater than the uncertainty associated with the emission scenarios.
The work is based on the cooperation established between the main research centres on the climate of the Pyrenees in Spain, France and Andorra. At the same time, it is in keeping with the need to offer a lasting and updateable initiative that will make it possible to make useful diagnoses of climate behaviour with a broad future projection.
José M. Cuadrat, CLIMPY Project Manager
In addition, here are 3 press articles confirming this increase in temperatures in France, Spain and the Occitan region.