Above 3.5 degrees Celsius it is estimated that the average air temperature can increase in the wider urban planning complex of Athens during 2041-2070 in relation to the period 1971-2000, as a combination of the effects of climate change, based on the new scenarios and specifically the worst scenario of the United Nations Intergovernmental Panel on Climate Change, and the urban heat island.

This he finds among other things EKPA research and the professor and member of the European Union’s Scientific Committee on Climate Change, Constantinos Kartalis, in the context of the CLIMPACT 2 research project. At the same time, it is pointed out that an increase of this size will significantly worsen the thermal risk in Athens during the future period 2041-2070 . The focus of the research is the thermal risk in Athens with the wider urban complex of the city being categorized into five classes of thermal risk (very low, low, moderate, high and very high). Taking into account various parameters, the research also concludes that during the current time period, the central areas of the wider urban complex of Athens as well as Piraeus and municipalities in its wider area, show a very high thermal risk, while the thermal risk takes the lowest values ​​mainly in the areas to the northeast and east of Athens.

As the EKPA professor and member of the European Union’s Scientific Committee on Climate Change, Konstantinos Kartalis, points out to the Athenian-Macedonian News Agency “In recent years, there has been an increased frequency, intensity and duration of extreme weather events in the region of the Southeastern Mediterranean, with the effects of these phenomena also reflected in Attica. These phenomena are mainly related to very high temperatures and heat waves. These records do not constitute a climatic peculiarity of Greece, but essentially follow the temperature observations on a global scale, which demonstrate a distinct warming of the planet in the last 150 years due to human intervention. Additionally, it has been observed worldwide in recent decades a particularly high number of heat events, which also tend to be more frequent, last longer, and more intense. The heat episodes in Attica in the years 2022 and 2023 are characteristically mentioned, which combined high temperatures with a long duration, which worsened the thermal conditions in many urban areas.

According to Mr. Kartalis, in general cities are particularly vulnerable to climate change as this is added to the Urban Heat Island (UHT), i.e. the fact that urban areas are warmer than neighboring rural areas due to lower vegetation cover, stronger absorption of solar radiation and man-made heat sources (cars, buildings, industrial and craft sources).

With the Urban Heat Island as a whole generally being stronger at night, as it is largely shaped by the slower cooling rate of urban areas compared to the countryside, the most unfavorable heat load and higher energy consumption in buildings for cooling appears to occur during lunch hours.

As Mr. Kartalis underlines, a large number of studies by EKPA and other organizations in Greece have shown that climate change affects the demand for electricity. For example, he points out, electricity demand in urban areas has been estimated to increase from 0.5 to 4.5% (depending on the study area) for each degree of increase in air temperature. Specifically for Athens, the above increase in electricity consumption is of the order of 4.1% for an increase in temperature by one degree Celsius. In addition, according to Mr. Kartalis, the thermal effect of the city is closely related to a strong negative impact on the health of its inhabitants, especially regarding the most vulnerable groups of the population. “The comparative study of daily mortality data from cardiovascular and respiratory causes in Athens led to the result that the mortality of people over 65 increases in high and extreme temperatures by 20% and 35% respectively”he emphasizes.

In the context of the research project CLIMPACT 2, a project referred to the National Network for Climate Change and supported by the General Secretariat of Research and Innovation, the thermal risk in Athens was assessed by the EKPA using a combination of parameters such as the soil surface temperature (LST) , the vegetation index and the population density in terms of people over 65 years old. As a result, the wider urban complex of Athens was categorized into five (5) classes of thermal risk: very low, low, moderate, high and very high.

As can be seen in the following map, the central areas of the wider urban complex of Athens as well as the Municipalities in Piraeus, show a very high thermal risk, while the thermal risk takes the lowest values ​​mainly in the northeast and east.

At the same time it was also appreciated the temperature difference for the time period 2041-2070 compared to the period 1971 – 2000 using the SSP5-8.5 scenario which is part of the new set of United Nations Climate Change scenarios and is the most unfavorable (essentially assuming that it will continue unabated the use of fossil fuels and consequently will further increase the concentration of greenhouse gases, and especially carbon dioxide, in the atmosphere). In particular, for the assessment, as Mr. Kartalis explains, three climate models were used whose results were captured on an improved spatial scale of the order of 12.5 km x 12.5 km, with the use of machine learning and the use of a series of predictive parameters such as the average surface flux of solar radiation, wind speed at 10 meters from the surface, etc.

As can be seen in the figure below, attached, the increase in temperature for the wider urban complex of Athens exceeds 3.5 degrees Celsius, as a combination of climate change and the urban heat island with the exception of the coastal zones and the areas further north of Athens. It is reasonably estimated that an increase of this size will significantly worsen the thermal risk in Athens during the future period 2041-2070.

“In order to identify the solutions that will strengthen the resilience of a city to climate change, you need to study it in depth, using terrestrial and satellite data as well as the results of climate simulations. The CLIMPACT research program is an innovative research and synergy between Universities and Research Centers in Greece. Essentially, it gives space to advanced research on the extremely critical topic of climate change, helps to understand the complex atmospheric and climate processes and facilitates the development of innovative tools both to capture climate impacts and, above all, to identify the necessary solutions to strengthen resilience of Athens and other cities in Greece in the high temperatures and heatwaves”notes the professor of Environmental and Climate Physics at EKPA, Mr. Kartalis.