Introduction 

By 2050, it is estimated that 68% of the global population will live in urban areas, while in Europe, as of 2018, around 74% of the population lives in cities, a figure expected to rise to 85% by 2050. In Greece, half of the country’s population is concentrated in a limited number of urban centers, with a population of more than 50,000 inhabitants, and mainly in the two metropolitan areas, Athens and Thessaloniki. Based on EUROSTAT data, the metropolitan area of Athens is among the ten most populous regions of the European Union, with a population of approximately 3.5 million inhabitants. According to the latest population census (ΕΛΣΤΑΤ, 2021), the greater metropolitan area of Athens gathers approximately 1/3 of the country’s population. This trend is expected to remain stable in the coming years, given the estimates of population decline in medium and small-sized cities, primarily due to population aging, combined with an increase in population concentration in large urban centers.  

In Greece, the high population density and the densely built urban fabric found in large cities, combined with limited green spaces, strain the urban microclimate. For example, we find cities with a population density higher than 10,000 inhabitants/km2 and a green space coverage of less than 20% of their total area. Meanwhile, the building stock of the country, which consists predominately  (95.4%) of residential buildings, largely lacks any form of insulation, given that the majority of them were built before 1980 (1st application of the Buildings Thermal Insulation Regulation). As a result, they are particularly vulnerable to external weather conditions and their fluctuations.  

Impacts of Climate Change 

According to the sixth report of the Intergovernmental Panel on Climate Change (IPCC), in urban areas, the observed climate change has caused adverse effects, among others, on basic infrastructure. The impacts of climate change on the built environment are closely linked to both the increase in extreme weather events and the damage they inflict, as well as the alterations in living conditions within urban areas. These changes stem from anticipated shifts in climatic conditions, such as the rise in average temperatures and the frequency of heatwave phenomena.  

The increase in the mean temperature and the frequency of heatwaves is expected to raise energy demand for air conditioning and reduce thermal comfort in urban centers and in indoor spaces, while simultaneously intensifying the Urban Heat Island (UHI) effect. Due to the reduced frequency of rainfall in the summer, increased incidents of subsidence and prolonged periods of drought are expected. The problem of drought is exacerbated by the increased demand for water, particularly during the summer months. In the coming decades, Athens is projected to experience a decline in overall rainfall levels, while simultaneously facing an increase in the frequency of extreme rainfall events. This shift is likely to lead to significant changes in the annual total of precipitation. The increased frequency of storms is likely to cause damage to buildings and infrastructure, as well as congestion of drainage systems resulting in more severe flooding events. The expected increase in the frequency and intensity of extreme weather events is estimated to increase the risk of damage to the built environment (increased risk to human life, damage to infrastructure, cultural heritage monuments, etc.), while for coastal cities there is an additional risk due to rising sea levels. On the other hand, effects with a positive sign are also expected, such as the reduction of energy demand to cover heating needs in winter, due to the increase in mean temperature, as well as the reduction of damages caused by frost on buildings and roads network.  

Suggested Solutions 

The built environment sector is one of the fifteen (15) priority sectors included in the National Adaptation Strategy (NAS) (MEEN, 2016). The indicative actions and measures proposed in the Strategy for the sector’s adaptation to climate change impacts aim to:  

• integration of climate change adaptation in the legislative and regulatory framework of the sector (e.g. update of the Buildings Energy Performance Regulation), 

• integration of climate change adaptation consideration and actions into local level development planning (e.g. urban planning adaptation), 

• implementation of climate change adaptation measures, such as measures aiming at reducing pressures on critical resources (e.g. efficient use and saving of energy in buildings by using energy-saving technologies, energy-efficient systems and equipment, other energy-saving techniques, building buildings with zero energy consumption, as well as use of RES/alternative energy sources in buildings),  

• implementation of measures aiming at reducing the intensity of climate change impacts (e.g. improving thermal comfort and microclimate conditions in outdoor spaces through the redesign of public spaces based on bioclimatic principles and increasing greenness, improving thermal comfort conditions in buildings, by integrating greenery into the structural elements of buildings and using innovative materials in the renovation of old buildings and in the construction of new ones, reducing rainwater runoff by reducing impenetrable surfaces and changing the relationship between built space and greenery),  

• improvement and acquisition of innovative knowledge on the impacts of climate change and adaptation to it (e.g. identification of a holistic methodology for the assessment of the vulnerability of building infrastructures in the terrestrial and coastal environment),  

• citizen information and awareness (e.g. building user education and improved performance through behavioral changes).  

(*) The main purpose of the proposed measures and actions is to serve as general guidelines supporting adaptation efforts in the Built Environment sector and consequently the resilience of cities to the expected climate change impacts.  

Related Links

• Urban Agenda for the EU and European Urban Initiative
• European Platform for Adaptation to Climate Change – Climate-ADAPT – Urban Environment Sector 
• European Platform for Adaptation to Climate Change – Climate-ADAPT – Buildings Sector