Despite Being Distinguished as the 2020 European Green Capital, Lisbon Has Lost Public Green Areas over the Previous Decade

Abstract

With the objective of assessing Lisbon’s environmental improvement and sustainable development, we measured the changes in Lisbon’s vegetation cover over the 2010–2020 timeframe considering three categories: public green areas (PGA), street trees (ST), and urban green infrastructure (UGI). We calculated the vegetation cover (m2), vegetation cover per resident (m2 person−1), and % of vegetation cover. PGA and ST covers were made available by the municipality, while UGI cover was estimated from the NDVI calculated from multispectral satellite images (Landsat 7–8). Since only the PGA cover decreased 2% (the ST and UGI covers increased 38% and 5%, respectively), Lisbon has lost PGA over the previous decade. The values of PGA per resident were below the minimum value of 12 m2 person−1 at the city scale and in most parishes (19 parishes out of 24 in 2020). While the values of % of UGI were above the desired value of 30% at the city scale, in 2020 there were three parishes with values below the minimum of 5%. This information is important to prioritize measures that promote sustainable urbanization in those parishes. Our study raised many questions, suggesting the need to standardize the methods for measuring the urban vegetation.