You don’t have to be a meteorologist to know that in Galicia it always rains more than in Murcia. It is for this reason that in the reports published by the State Meteorological Agency (Aemet) at the end of the hydrological year this difference does not appear. In the last one, however, it was what stood out the most: “Although it is common for it to rain more in the northwest of the peninsula than in the southeast, This situation was much more pronounced than usual during the last hydrological year.
In total, 671 liters per square meter were accumulated; i.e. 5% more than the normal average for the reference period 1991-2020. With these figures, the hydrological year 2023-2024 was wetter than the previous three years. Despite this, some regions, such as those of the Levant, the Canary Islands and the Balearic Islands, have not managed to emerge from the drought situation.
In the southeastern tip of the peninsula, not even 120 have been exceeded. l/m². The situation is worsening in certain areas of the Mediterranean coastwhere 80 l/m² has not been achieved. In the northwest of the peninsula, however, 1,500 l/m² was exceeded. This figure was also reached in the eastern part of the Cantabrian Sea, in the Navarrese and Aragonese Pyrenees and in some points of the western central system.
This inequity is also seen in the precipitation received by the watersheds. Thus, while the Tagus basin received rains 127% higher than normalin the Segura basin, barely 50% of normal values were reached. Concerning the provinces, Alicante, Almería, Murcia and Valencia are the most affected by a meteorological drought which, in certain areas of the south of the peninsula and in a good part of Catalonia, has already lasted three years.
What is the reason
“What we have observed in recent years is that a trend is beginning to dominate in the atmospheric circulation on the peninsular territory, which accentuates the difference between the maximum precipitation in the northeast of the peninsula and the minimum in the south -is,” he emphasizes. to EL ESPAÑOL the Meteored meteorologist, Jose Miguel Vinas.
This model causes still drops of cold air on the Atlantic slope. On the opposite side, however, “there is a more permanent dominance of a ridge of warm air.” Aemet spokesperson Rubén del Campo also believes that the distribution of precipitation during the last hydrological year reveals “the predominance of Atlantic storms”.
Although it is a “subject under study,” Viñas points to global warming as the main cause of the increasingly uneven distribution of precipitation: “Those known as Hadley cells they extend towards the north“. This The atmospheric circulation model is one of those responsible for the circulation of heat from the equator to the poles.
“In this situation,” the meteorologist continues, “what happens most often is that the ridge of subtropical warm air ‘invades’ more and more space on the territory of the peninsula.” This causes the western flank to produce cold entries with storms arriving with very heavy rain.
Meteorologists agree that this change is not only happening in our country. In 2021, a study published in the journal Science Advances already warned that due to the increase in temperatures caused by climate change, The precipitation pattern was changing. at the global level.
Based on climate model projections under a high emissions scenario, the authors warn that about two-thirds of the Earth’s surface will face a “wetter and more variable” climate. This means there are more oscillations between wet and dry areas.
The researchers of the aforementioned study also predict that the increase in precipitation variability will be greater than the increase in average precipitation: “As the climate warms, climatologically humid regions will generally become wetter and dry regions drier.”
Towards greater variability
“In this context of global warming, we are going to have more variability in terms of precipitation,” he says. Marta Almarchameteorologist at Eltiempo.es. “Everything tells us that the trend will be that already wet areas will be even more so; and dry areas will also be drier.”
Almarcha believes that “we have no solution” to reduce the difference between the northwest and southeast of the peninsula. “We have no choice but to adapt to what happens to us“And the climate will not only be more uneven, but also more extreme: “Perhaps in one day the precipitation that has not occurred throughout the year can be overcome.”
Although these extreme phenomena can also have negative consequences, as Viñas points out: “Storm Berenice, for example, will leave precipitation in areas where it rains well. there will be problems due to excess water“.
Regarding the increasingly uneven contrast in precipitation, the meteorologist is a little more optimistic than Almarcha: “We need to start applying both mitigation and adaptation measures. This year, for example, we found that in many interior regions water shortage has caused a lot of damage“.
And, although climate models already predict that precipitation variability will increase in the future, some work has already shown that this variability has already increased since the last century; more precisely, 75% in the areas studied (Europe, Australia and eastern North America). The data indicates that Daily precipitation variability increased by 1.2% per decade on a global scale.
