Assessing vulnerability and strengthening the resilience of the urban fabric through blue and green infrastructures: The case of the Thessaloniki’s Urban Agglomeration

Abstract

Climate change is the greatest challenge facing humanity in the 21st century. The effects of its consequences become more visible in areas with intense human activity. Continuous urban expansion, occupation of vacant land for housing and increased energy consumption diversified the microclimate of cities. The Urban Complex of Thessaloniki, as a densely built, coastal urban network, is considered vulnerable to extreme weather events, especially in high temperatures. The dual objective of the present study is, firstly, the development of a spatial model which will assess the vulnerability of the Urban Development Complex of Thessaloniki from risks related to the climate and high temperatures, and in a second stage, the development of an infrastructure network based on the ecosystem approaches, which will contribute to vulnerability reduction. Data were collected from the "Landsat - 8" satellite and other scientific sources for visualization in a GIS environment, focusing on the urban heat island phenomenon and green infrastructure. The use of specific spectral indicators, related to the levels of vegetation, building stock, humidity and temperature, led to useful conclusions and statistical correlations, resulting in the identification of vulnerable areas due to high temperatures. In addition, the analysis of the green indicators of the urban complex of Thessaloniki, pointed out serious inequalities between spatial units, which increases the degree of vulnerability of specific areas. International experience has proven that the integration of ecosystem approaches in urban planning has the ability to make an area much more resistant to risks related to climate change. The introduction of "green" and "blue" infrastructures in the urban fabric has multiple benefits, as on the one hand it reduces vulnerability, on the other hand it contributes to upgrading the quality of life of the city's inhabitants. Taking into account the results of the analyzes as well as the special characteristics of the urban complex of Thessaloniki, it is proposed to create a network of "green" and "blue" infrastructures, in order to strengthen the resilience of Thessaloniki through ecosystem approaches.