We find that extreme and severe weather phenomena have tripled in Thessalonikiin relation to previous years and their consequences due to climate change, but also due to man-made interventions and the lack of anti-flood measures, pointed out meteorologist Michalis Sioutas, at the TEE/TKM event for World Environment Day on the subject: “Climate Change – Effects on the Coastal Zone – Anti-flood shielding of Thessaloniki”. He also emphasized that “if current conditions are maintained, based on the most likely scenario, it is predicted that five to eight flooding episodes will occur per year in the Thessaloniki area in the next decade, 2023-33”.

In the past, as he said, extreme phenomena happened once or twice a year, maybe even none, while in recent years we have had six or seven such episodes with large-scale effects in Thessaloniki. The natural and urban environment has become very vulnerable to natural disasters and extreme weather events, resulting in frequent flooding, landslides, environmental changes in the coastal areas, where we find significant erosion.

The event was coordinated by the head of the Permanent Working Group for Physical, Technological and other Disasters of the TEE/TKM, Civil Engineer Vasilis Lekidis. Welcoming the event, the President of TEE/TKM, Giorgos Tsakoumis, underlined that coastal erosion is an issue that has recently begun to concern the scientific community with such intensity, as it is expected to significantly affect economic activity in the future. He also underlined the role of the chamber in submitting proposals and prompting rapid measures to mitigate the risks of the estimated effects.

The deputy governor of Technical Works of the Central Macedonia Region and former president of TEE/TKM, Paris Billias, during the greeting – also on behalf of the Regional Governor, Apostolos Tzizikostas – but also during his introduction, he underlined that the PKM has already set up an observatory of the evolution of the phenomenon of coastal erosion. “This is something that has always happened. The coastline today has nothing to do with what it was hundreds of years ago. However, today, and in the immediate future, the effects are recorded and will be much greater, due to the form and intensity of human activity” he underlined and noted that “there is ambiguity as to who is the body responsible for managing and dealing with the phenomenon “, while “the time required to mature related projects is long, since a coastal engineering study can take up to three years, a fact that definitely needs legislative regulation”.

Regarding the anti-flood projects, Mr. Billias emphasized that “the master plans we are drawing up are good, but they should be accompanied by the corresponding resources, both financial and in terms of scientific potential” and added that they are being developed by the Ministry of Infrastructure and the Ministry of Infrastructure and Transport 16 projects and studies concerning the anti-flood shielding of Thessaloniki, while proposals for 15 new studies have been submitted.

The need for immediate measures was also noted by the Deputy Mayor of Technical Works of the Municipality of Thessaloniki, Ephraim Kyrizidis, welcoming the event on behalf of the Mayor, Konstantinos Zervas. He noted that the Municipality has submitted several proposals, especially regarding the management of the streams, an issue that has created many dead ends, since until 1990 the streams were considered suitable for the location of constructions for public purposes.

In any case, according to the conclusions of the event, Greece faces the risk of “submergence” of important parts of the coastline in various regions (Attica, Thessaloniki, Peloponnese, Crete, Dodecanese, etc.) within the next decades – with the corresponding cost for the economy and for local communities – if measures to address the effects of climate change are not taken and pay off.

Referring to the recorded but also to the estimates for future effects of climate change, the Meteorologist Mr. Michalis Sioutas described a Thessaloniki with large areas around the current Delta of Axios, submerged by the rise of the sea level to a depth of 50-100 years, but also the Aristotelous square of Thessaloniki, submerged up to the height of Tsimiski street.

The recent UN report, Mr. Ciutas emphasized, highlighted the following: “Extreme weather events and man-made climate change in the last 50 years have claimed the lives of two million people and caused damages of 4.3 trillion. dollars in the period 1976-21. In the period 1976-21 there were 11,778 major disasters due to climate change. In 2020-21, deaths caused by extreme weather events were 22,607 globally, but would have been around 50,000 without early warnings, which save lives.”

He emphasized that more than 90% of deaths from these phenomena occurred in the poorest, developing countries. Rich countries have been hit hardest in economic, monetary damages. Deaths are falling, but the economic impact of weather-related disasters has skyrocketed. Economic losses had increased 7-fold from 1970 to 2019, rising from $49 million per day in the 1970-80s to $383 million per day in the last decade 2010-20.

Mr. Siutas added that, “Infrastructure such as rainwater drainage pipes were designed for smaller amounts of water and population and as a result are now insufficient. The necessary works must be done immediately, but also new technological means and early warnings that save lives must be used to prevent the risks of losing human lives”, he underlined.

The Professor of the Department of Agronomists and Topographical Engineers of AUTH Giorgos Vergos, presented the methodology and data of the Observatory of the Central Macedonia Region, which through the processing of geospatial and other data confirm the estimates for the risk of future submergence of areas of the coastline. As he said more specifically, “the area of ​​Axios, as well as the coastal areas of Perea, Epanomi and the airport “Macedonia” are at risk of severe flooding in the future”. Among the proposed intervention measures, he cited the need for new urban planning legislation with a review of land uses in coastal areas, measures to restore coastal habitats and new codes and regulations to build infrastructure to withstand coastal erosion and storm surges. .

The designer of Offshore Engineering – Port _ Hydraulic Works, Antonios Valsamidis, presented various models of simulations of measures to protect coastal areas, while referring to the effects of climate change he noted that “the general morphodynamic trend of the evolution of the coasts in combination with the rise of the sea level could destroy half of the sandy beaches worldwide by the end of the century” , while on the contrary “the noticeable reduction of greenhouse gases could reduce by 40% the tendency of coastlines to recede”.

The Head of the Directorate of Strategic Planning, Projects and Development of EYATH, Alexandros Mendes, presented the efforts of EYATH in the extensive water supply and drainage network that it controls, for its maintenance and cleaning, as a measure to prevent flooding phenomena. Speaking about the problems caused in recent years in Thessaloniki in rain events >15mm, he reported 929 problems (77.4 per year approximately) in the period 2010-2022, which mainly concern ground floor and basement flooding due to blocked grates or blocked ducts respectively. rain events >25mm in the same period, around the center at least 75 points where flooding was recorded more than twice are recorded.

Zisis Mallios, Assistant Professor of the Civil Engineering Department of AUTHspeaking about the socio-economic effects of climate change, presented climate scenarios for the next 50 years, according to which in Greece, the temperature will increase from 2°C (RCP 2.6) to 3.4°C (RCP 8.5), hot days in Greece will increase by 15-20 days per year, rainfall will decrease by 10% to 25%, high fire danger days will increase by 15% to as much as 70%, extreme weather events will be much more frequent and sea level rise predictions they will range from 0.2 to even 2 meters by 2100.