The scientific community is sounding the alarm for fear of an increase in the frequency of phenomena such as the deadly floods that hit the Valencia. The increased sea temperatures in recent years, especially in the Mediterranean, are causing increased instability throughout the region, they say.

“In addition to the change in global circulation patterns and the ability of the air to hold more moisture, we have in recent years in the Mediterranean a remarkable increase in the temperature of its waters. That is, we are talking about 2-3 degrees more temperature, which increases the instability extremely in the whole region”, its former director explains to the Athenian-Macedonian News Agency National Meteorological Center of EMY and member of the Scientific Risk Assessment Committee of the Ministry of Climate Crisis and Civil Protection, Dimitris Ziakopoulos. In Greece, although the rainfall recorded is significantly reduced, the fear of more intense rainfall is visible. “The number of rainy days in our country has been significantly reduced, but when they come, however late they come, they are usually stronger than before. That’s the pattern and that’s what scares us.” notes Mr. Ziakopoulos.

According to the assistant professor of Natural Disasters of EKPA, Michalis Diakakissuch extreme phenomena are becoming more and more frequent, which was also the subject of the researchers’ study. “We tried to look at a period of time which is very long because you cannot assess their presence and if they increase or decrease if you look back 10-20 years. So we looked back 140 years in the Eastern Mediterranean and in this context we saw with relative surprise I must say that we had at least 20 incidents with over 80 dead, some had 100, some 150, some 200, some 500 dead. What we have seen is that we have an average recurrence rate of once every 9 years in the wider Eastern Mediterranean region. So this seems to be quite a bit more common. If we go to the Balkans in our country and the rest of the Balkans we will see that we have an annual probability of about 2.5% of such an event occurring it is not very high but it is not as low as we would expect so there is realistically a chance of seeing something like this and in our country. And of course such a storm that will fall is of great importance, i.e. if it falls in an area such as the plain of Thessaly where the waters move more gently, where we have a lot of agricultural and forest areas and areas of natural vegetation and a smaller part of the urban environment, then the damages would certainly have been catastrophic but they would not have been as devastating as they could have been if they had fallen in an urban environment like that of the Athens basin, i.e. yes the destruction was gigantic but on the other hand if it had been in a very dense urban area like Athens then we would have many times more destruction like what we saw in Valencia”, underlines Mr. Diakakis.

For Mr. Diakakis, the phenomenon that hit eastern Spainit was more like the floods in Mandra. “It looks like Mandra’s but there are also some small differences. The first difference is that the size of the river in Valencia is much larger than that of Mandra, we are talking about 2/3 of the Pinios the river of Valencia, while that of Mandra was a very small catchment, a small dry river and also the extent of the flood phenomenon in Mandra occurred in a small town of 12,000 inhabitants, while in Valencia we are talking about a city of 800,000 – 1,000,000 inhabitants in the wider area. So the size, the sizes differ,” points out and emphasizes:

“It is certain that we will often see such phenomena. If you think in the last decade, how many times have we seen in our country, which is a small area of ​​the Mediterranean, such phenomena with dead people, as in Mandra, in Evia in the summer of 2020, in Daniel, in Janos. We see such phenomena very often now, if not every year almost year after year.”

Extremely dry October almost all over the country – Fires up 16% this October

At the same time, according to European Drought Observatory, until early October 2024, the Combined Drought Index (CDI) indicates drought warning conditions in a number of areas, including southern Greece, while some areas in the Mediterranean region – particularly southern Italy – eastern and southern Spain and Greece , are in “red”, under conditions of persistent drought, with effects on vegetation.

Indicatively, according to records of 118 stations of the network of the National Observatory of Athens/meteo.gr, this year’s October was extremely dry almost throughout the country:

• At 95 stations the amount of rain was zero or minimal, showing a deviation of 80 to 95 % with respect to normal October values.

• At no station was the monthly amount of rain higher than the average value of the last 15 years

It is also noted that according to the stations’ records, this year’s October was the driest of at least the last 15 years (with the exception of areas of Northwest Greece such as Corfu and Ioannina) where this year’s October was the second driest.

It is worth noting that especially fires are also increased in Greece this October. In particular, according to data from the Fire Department, fires show a 16% increase as in October this year there were 1007 fires compared to 867 in the corresponding month last year. In addition, as reported by competent officials from the Fire Department, the lack of rain, the prolonged drought and the increased number of of fires led to the extension of the ban on the use of fire (and not the fire season) until November 15 in many areas of the country.

What caused the deadly floods in Valencia

In the case of the wider region of Valencia, as Mr. Ziakopoulos explains, a thermodynamic cause worked, which is essentially related to a low, cut off from circulation, which stood over the region, the wider Spain-Morocco region.

“So that gave the root cause, the large-scale cause. However, two things worked against the great intensity of the storms. First, the morphology of the land, that is, the relief, and secondly, a warm and moist easterly, south-easterly current, which blew in the area of ​​eastern south-east Spain, which came from the Alboran Sea, but also mainly from the Balearic Sea . Therefore, since the sea was much warmer than the season and blowing this current, it first brought more moisture and heat to the Valencia region, with what this means for the intensity of the phenomena, but it also played a feeder role. That is, the warm and moist air masses over Valencia arrived, the condensation took place, that is, the expansion in the form of storms, but the water that fell, that the clouds lost, was constantly replenished by the new amounts of moisture and heat that came from the Mediterranean. This worked in terms of the duration of the phenomena, which was not short, it was quite long, as for eight hours we had this phenomenon continuously.” notes Mr. Ziakopoulos while pointing out that the hourly intensity of 160 mm of water per hour, which occurred in the Chiva region, is so great that in any region of the world it is almost impossible for the infrastructure to withstand it. “Of course we are also to blame for this, as a human species because we have increased the risk of floods. We have urbanized areas. Therefore, in an urban area, asphalt and cements, in effect, cease to absorb, prevent the absorption of water from the soil, increasing surface runoff, that is, flooding, the risk of flooding. Also, we have dammed up the riverbeds, we have reduced, we have almost eliminated in many areas, the riverbeds and the streams, which are the natural pathways of the water, and we are paying for it. There are the burnt ones, on the other hand, and, in general, the change of land use, there are the deforestations. All this has increased the dangerousness of the phenomena, and it is not only in Spain. In all countries, of course, including our country.” emphasizes Mr. Ziakopoulos.

According to Mr. Ziakopoulos, every autumn, the distribution of strong storms in all the Mediterranean regions shows a maximum, in terms of intensity and total rain heights.

“Climatology has shown us that from Spain to Turkey and Cyprus and in the northernmost countries, on the northern coast, on the southern coasts of Europe, flooding phenomena are observed during the autumn. This is the climate of the region and the causes are basically that the Mediterranean is a source of heat and humidity. In summer and autumn, warm and moist air masses accumulate in the lower layers of the atmosphere. Higher up the masses are dry but when a dynamic cause comes as was the low in Spain or another disturbance of a similar type then we have a release of this great instability”points out Mr. Ziakopoulos, however he emphasizes that now the patterns of planetary circulation have also begun to change, i.e. the patterns we knew until now. “The reasons are, first of all, that the atmospheric circulation “the planetary atmospheric circulation” has been “interrupted” by global warming with what this means for the intensity and distribution of the phenomena.

In addition, let’s take into account that the amount of water vapor, the moisture that the air can hold, has increased”, he emphasizes while adding that in addition to the change in global circulation patterns and the ability of the air to hold more moisture, in recent years in The Mediterranean is seeing a remarkable increase in the temperature of its waters.

For his part, regarding the phenomenon that affected the wider region of Valencia, Mr. Diakakis explains that it was a barometric low which persisted in the same area and had come in front of warm air masses which have a lot of moisture and which come from from the Mediterranean, which at this time of the year is unusually warm has unusually high temperatures due to very strong temperatures in recent years and especially in summers all over the planet. “So on the one hand the very warm sea two and three and four degrees above normal that feeds these systems with moisture the cold air mass that’s in the Valencia area and it’s been there for several days and that’s triggering a storm which becomes more intense precisely because it is fed by the warm sea. This is the essence of things and I say this because this is also related to climate change, the warm sea, that is.” notes.

About it how can we manage such kind phenomena, Mr. Diakakis emphasizes that it is not something that reverses or nullifies the risk. “The risk will remain high in the coming years and decades and the actions that humanity or our country in particular can take are on multiple time scales. We can follow the long-term strategy that will reverse climate change, which is the big problem we are facing, something that must be done at a global level, specifically for our country, of course, a long-term strategy of moving away from flood risk zones, that is, socio-economic activities our properties, our infrastructures to leave so that we can open more space for the water to go to the sea unhindered, of course to invest in anti-flooding projects and mainly those concerning mountain hydrology, i.e. to prevent erosion and to prevent the intense runoff from the mountain especially in relation to fires and from there on, of course the new technologies with early warning systems, applications such as 112 and of course the information and awareness of the world and its education plays a very important role mainly so that we do not have victims”he emphasizes.