There is an undeniable allure when it comes to natural green spaces, and it’s been shown that simply viewing vegetation can produce beneficial psychological and physiological effects on people. The relevance has never been more important as it is estimated nearly 70% of the world’s population will be urban dwellers by 2050. 

Historically, green spaces have been identified as a component of public health. Outdoor green spaces have been seen an an integral role in supporting citizens as a refuge from overcrowding and the proliferation of disease. In a journal article from Karen R. Jones (2018), she extracted an example from French history in which Henry IV “established the Place Royale (now Vosges) in 1605 out of concern that the people of Paris needed ‘a place to promenade’ as they were closely pressed together in their houses”, thus exemplifying the long held view of green spaces serving a function of health and restoration, and the need for people to have access to open spaces (p.44). This sentiment is extremely relevant by virtue of climate change, increasing urban density, and rising mental health concerns. 

Green infrastructure cools cities, manages water, reduces heat stress, noise pollution, and maintains biodiversity.

Green infrastructures such as green roofs, vertical greening, city parks, and urban gardens are an approach to help mitigate urban heat island effects (UHI) in the summer. UHI is a microclimate which explains the temperature in cities being hotter than the surrounding regions. This can be due to several factors such as: lack of green space, dark and impermeable materials used in the infrastructure of the city-roads, parking lots, sidewalks, buildings, and rooftop materials, and energy consumption, and high emissions of air pollutants. An enormous amount of urban landscapes consist of impermeable and dark materials which absorb energy from the sun and create heat, thus contributing to higher heat stress. This can be noted between urban dwellers and rural dwellers, where urban areas are usually hotter than the rural regions (Aram et al., 2019). 

In contrast to UHI, other microclimates such as Green Space Cool Island (GCI) and Pocket Space Island (PGS) have been identified as possible strategies to mitigate urban heating. These refer to the ability of large green spaces with trees, grass, shrubs, and water bodies (GCI) and small pocket spaces, such as a small city park (PGS), which can create a cooling dome that is cooler than the surrounding areas. Studies have shown reductions in air temperature in these green microclimates compared to the surrounding city temperatures, and these “green” microclimates can be integrated into urban design as a tool for public health to reduce heat stress (Aram et al., 2019, Wu et al., 2021). 

Incorporating green spaces into the city, also known as “urban greening” offers several benefits for city residents and workers to retreat and cool down in the scorching summer months. It brings to mind how people flock to the shade of a tree in a city park; trees and green foliage is a resource in combating the heat, and public park seating under the protection shade is a hot commodity compared to seating exposed to the afternoon sun. 

Among other benefits that green infrastructure provides is rainwater runoff management and further cooling of the air. Soil is permeable and helps filter water, allowing plant roots to absorb water through evapotranspiration, and then releasing water back up through vapor which cools the surface and air temperature. 

Furthermore, urban greening can produce and protect biodiversity through providing a habitat for wildlife such as birds, insects, butterflies, bees, and vegetation such as trees and shrubs provide noise reduction and air purification. 

Urban green space supports social and mental health. 

Connection with nature is an important aspect of our health and well-being. ‘Nature connectedness’ means the relationship we have to the natural environment, and this can be increased by our positive experiences with nature, and the more positive 'nature connectedness' one has, the more likely they will make pro-environmental decisions. 

We are very much a part of nature, however, our increasing urbanization and degradation of natural environments are cutting generations apart from a relationship and appreciation for the natural world. An increasing number of studies have found that people associate mental health and their general health with nature connectedness, and identified associations with mental distress decreasing with increased visits to green and blue spaces. 

White et al. (2021) found that “greater nature connectedness was positively associated with positive well-being and negatively associated with both mental distress and depression medication use” (p. 7). Nesbit et al. (2020) found that respondents who lived near high-density tree canopies reported more vitality and reported less mental distress. Research from Mittermüller et al. (2021) recommended cities to implement “visual green elements at eye level (e.g., green facades, shrubs, or planters) to increase the “naturalness” of stressful urban settings, since our results showed positive psychological benefits achieved by urban greenery” (p.49). In line with these results is the landmark research from Ulrich (1984) that found patients recovered from surgery faster and used less pain medication when their hospital room had a window with a natural landscape view, compared to those who had a window view of a brick wall. There is a health promoting element to viewing and being in proximity to nature. 

In urban areas, there is a greater potential for a nature disconnect to as accessibility to green spaces can be low. Urban areas are also high in potential stressors such as noise, air pollution, traffic, high temperatures, and social density stress. With this in mind, there is promising research demonstrating how beneficial the incorporation of urban green spaces is for mental and social health. The WHO report on urban green spaces and health included the positive association of quality green spaces and social connection in the community. Urban green spaces can be potential grounds for developing social cohesion, such as civic engagement, volunteer opportunities, citizen-initiated projects such as the local, free and open to all exercise and healthy cooking program Fürth Bewegt, citizen science projects, and community gardening.

Public parks can also be a fitting spot for social recreation. Safe and visually appealing, maintained parks have a potential to be a hub for social activity and recreation such as: family picnics, a stage for local plays and performances, the location for festivals and dance classes, a go-to for walks with friends, a space for socializing with other dog owners, a popular choice for physical activity and group exercise classes, a venue for sporting events, and the space for children to play and connect with nature. Inclusive access to safe and appealing green spaces is critical for urban residents, as it is uncommon that most residents have access to a private garden space, in which they may rely on city green spaces for recreation, leisure, and shade during hot days. 

Green urban space examples-Tempelhof and rewilding projects in German cities.

Urban spaces can be transformed into inclusive public green spaces for activity and leisure. A perfect example of this comes from Berlin, where the decommissioned Tempelhof Airport consisting of 358 hectares was transformed in 2010 into a public open green space Tempelhofer Feld. Rather than selling the massive vacant space to developers, it was transformed into a sprawling public space for leisure and sport, including gardening projects, miniature golf, walking paths, sports designated areas, and protected wildlife areas for the endangered species, such as the skylark. 

Städte Wagen Wildn isis a government-funded project with local university partners dedicated to rewilding empty spaces in the German cities of Dessau-Roßlau, Frankfurt am Main, and Hannover. The rewilding projects have transformed deserted lots into thriving wildflower meadows rich in biodiversity. The care of these spaces has a more hands-off approach because organizers decided not to impede the reclamation of nature, thus seeking the opportunity to learn more about rewilding processes through observation. 

Interested in learning more about urban green spaces and recommended approaches for integration of urban green spaces? Read the German Federal Government 2017 White Paper: Green Spaces in the City-for a more liveable city' from the Federal Ministry for the Environment, Nature Conservation, Building, and Nuclear Safety. 

References

Aram, F, García E, H, Solgi, E, Mansournia, S. (2017). Urban green space cooling effect in cities, Heliyon, Volume 5, Issue 4, e01339, ISSN 2405-8440,https://doi.org/10.1016/j.heliyon.2019.e01339.

Jones, Karen. (2018) 'The Lungs of the City': Green Space, Public Health and Bodily Metaphor in the Landscape of Urban Park History. Environment and History. 24. 39-58. 10.3197/096734018X15137949591837.

Mittermüller, J., Erlwein, S., Bauer, A., Trokai, T., Duschinger, S., & Schönemann, M. (2021). Context-specific, user-centred: Designing Urban Green Infrastructure to effectively mitigate urban density and heat stress. Urban Planning, 6(4), 40–53. https://doi.org/10.17645/up.v6i4.4393https>https://doi.org/10.1126/science.6143402https

White, M.P., Elliott, L.R., Grellier, J. et al. Associations between green/blue spaces and mental health across 18 countries. Sci Rep 11, 8903 (2021).

Wu C, Li J, Wang C, Song C, Haase D, Breuste J and Finka M. (2021). Estimating the Cooling Effect of Pocket Green Space in High Density Urban Areas in Shanghai, China. Front. Environ. Sci. 9:657969. doi: 10.3389/fenvs.2021.657969