Intense fear of an increase in the frequency of phenomena similar to the deadly floods that have hit the region of Valencia in Spain has been collectively expressed by the scientific community. The Mediterranean region in particular seems to be in the “red” of the forecasts as the increased temperatures of the seas in recent years cause an increase in instability throughout the region.
In an interview with APE, Dimitris Ziakopoulos, former director of the National Meteorological Center, speaks for an increase in prices in Mediterranean temperatures by 2-3 degrees. He even points out that this is something that leads to heavier rains when they do occur. Despite the reduction in rainy days, any rainfall is now more intense and frequent, he notes.
Michalis Diakakis, assistant professor of Natural Disasters, reports to APE, that extreme phenomena appear more and more frequently in the Eastern Mediterranean, with at least 20 events that caused more than 80 deaths in the last 140 years.
With regard to Greece, the probability of occurrence of such phenomena is 2.5% per year, which is not high, but not negligible either. Referring to the flood in Valencia, Mr. Diakakis compares it to the floods in Mandra, but notes that the differences are significant, mainly in the size of the rivers and the population of the affected areas.
He specifically predicts that such phenomena will continue to occur, pointing to the many cases that have been seen in the country in recent years.
Additionally, the drought situation in Greece is alarming, with October recording extremely low rainfall and a 16% increase in fires compared to last year.
As for the flooding in Valencia, Mr Ziakopoulos explains that it was caused by a detached barometric low and warm, moist air masses from the Mediterranean. This combined phenomenon produced heavy rainfall, with hourly intensity reaching 160 mm, a situation that exceeded the strength of the infrastructure.
Climate change, according to scientists, increases the risk of flooding, as the heat of the sea leads to more moisture in the atmosphere. Adopting strategies to adapt to climate change, moving away from risk areas and developing flood protection projects are critical. Finally, public awareness and education can help prevent deaths and injuries from such phenomena.
Extremely dry October almost all over the country – Fires up 16% this October
At the same time, according to the European Drought Monitor, until the beginning of 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 in the south 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% relative to normal October values.
In 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 the number of fires in Greece is also particularly high 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 area, with what this means for the intensity of the phenomena, but also played a feeder role. That is, the warm and moist air masses over Valencia arrived, the condensation took place, 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 on hour, which occurred in the Chiva region, is so great that in any part of the world it is observed it is almost impossible for the infrastructure to withstand. “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 the release of this great instability”, points out Mr. Ziakopoulos, however he emphasizes that now the patterns have also started to change planetary circulation, i.e. the patterns we have known so far. “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 In the Mediterranean, a noticeable increase in the temperature of its waters is observed.
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 is in the Valencia area and has been there for several days and that triggers 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, namely the warm sea”, he notes.
Regarding how we can manage such 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 unimpeded of course to invest in anti-flooding projects and especially those concerning mountain hydrology, that is 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.
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Recent natural disasters caused by climate change
**Interview with Dimitris Ziakopoulos and Michalis Diakakis on Climate Change in the Mediterranean**
**Interviewer:** Today, we’re joined by Dimitris Ziakopoulos, former director of the National Meteorological Center, and Michalis Diakakis, assistant professor of Natural Disasters. Thank you both for being here. Let’s start with a pressing issue: the recent deadly floods in Valencia. Dimitris, can you explain what caused these intense weather phenomena?
**Dimitris Ziakopoulos:** Thank you for having us. The floods in Valencia were primarily caused by a detached barometric low over the region, combined with warm, moist air masses from the Mediterranean Sea. This combination led to extreme rainfall, with intensities reaching 160 mm per hour in some areas. The warming of the Mediterranean is fueling more moisture in the atmosphere, which amplifies these events.
**Interviewer:** It sounds alarming. Michalis, you’ve noted that extreme weather events are becoming more frequent in the Eastern Mediterranean. Could you elaborate on that?
**Michalis Diakakis:** Certainly. Over the last 140 years, we’ve recorded at least 20 extreme weather events that have resulted in over 80 deaths. While the annual probability of such events in Greece is relatively low at 2.5%, it’s significant enough to warrant concern, particularly given the increasing trend of intensity and frequency. The floods in Valencia serve as a stark reminder of what we might expect.
**Interviewer:** Dimitris, you mentioned the role of urbanization in exacerbating flooding risks. Can you explain that further?
**Dimitris Ziakopoulos:** Yes, urbanization leads to increased impermeability in our landscapes—more asphalt and concrete mean less water absorption and, consequently, heightened surface runoff. Additionally, land-use changes and deforestation diminish the natural pathways for water, increasing flooding risks across the board. We have essentially altered the environment’s ability to manage heavy rainfall events.
**Interviewer:** Michalis, could you also touch on the current drought situation in Greece? How does this connect to the flooding events we’ve observed recently?
**Michalis Diakakis:** The drought situation this October is severe, with significant deviations from normal rainfall patterns. Some areas recorded no rain at all. This persistent drought, coupled with the increased frequency of extreme weather events, creates a heightened risk of both flooding and wildfires. For instance, we’ve seen a 16% increase in fires this October compared to last year.
**Interviewer:** It’s clear that climate change is deeply intertwined with these weather extremes. What kind of strategies should we be considering to mitigate these risks?
**Dimitris Ziakopoulos:** Adopting effective adaptation strategies is crucial. This includes improving urban infrastructure to manage heavy rainfall, developing flood protection projects, and relocating at-risk communities. Raising public awareness and educating citizens on these issues can also play a vital role in preventing casualties during such extreme events.
**Interviewer:** Thank you both for your insights. It’s evident that urgent actions are needed to combat these climate-related challenges. We appreciate your time and the valuable information you’ve shared.
