Transformation towards Green Cities: Key Conditions to Accelerate Change

Cities worldwide are growing at unprecedented rates, compromising their surrounding landscapes, and consuming many scarce resources. In 2020, it is expected that 56% of the world’s total population will be living in urban areas [1], and this number is expected to increase to approximately 68% in 2050 [2]. As a consequence, this will increase the compactness of cities [3] and will also decrease the availability of urban green space. Vegetation in cities disappears, for example, through new housing, including through the infill of ‘empty’ spaces; adjusting of infrastructure; paving of squares with stone or cement; and the construction of business parks. Moreover, many people are also tiling their gardens [4]. In recent years, many Dutch municipalities have cut back on municipal green space and its maintenance. At the same time, due to changes in climate, temperatures in cities are rising and weather extremes are becoming a common phenomenon. Most (western-oriented) cities are facing a worrying loss of green space, decreasing levels of biodiversity, the increasing alienation of inhabitants (including children) from daily experiences of nature, the natural environment, food, and, lastly also, repercussions on health and the quality of life [5,6]. To offer a liveable environment in 30 to 50 years, cities must face these challenges head-on and strive to create green urban areas that build on liveable and coherent sustainable circular subsystems. In the WUR long read [6], seven reasons were identified whereby the importance of investing in green city development has been distinguished: reducing risk of flooding; cooling the city in the summer; contributing to better health and increased well-being; contributing to social cohesion; supporting biodiversity; attracting companies and investors; and, to conclude, boosting the value of houses and offices. Some practical starting points for the greening of cities can be found in papers by the likes of de Roo [7] and Tucci and Battisti [8].