Rona Schenk

Since there are more and more people living in urban areas it is important to provide worth living cities. This does not only require a highly developed public transport and a well-considered housing but also – and particularly – enough green area. Parks, roof gardens and green lanes for pedestrians and cyclists increase mental well-being, reduce health risks, may encourage a more sustainable lifestyle and support biodiversity (1). Therefore, green area is an effective element in order to achieve SDG number three and number eleven.

Urbanization and its challenges

The amount of people living in urban areas is increasing (2). Today more than half of the global population already live in cities2, estimations for the European region of the WHO even assume 75% (1). However, the trend did not reach an end. In the year 2050 more than 70% of the worldwide population is expected to be part of a city. (2)

The trend of urbanization brings several challenges humankind has to cope with. One of the most striking challenges is the increased exposure to pollution and noise which affects human health. But urban areas also reduce peoples access to nature what may have an impact on mental health. (1) Considering an increasing number of people is living in cities it is even more important to actively provide good surroundings. Otherwise the SDGs number three and number eleven – good health & well-being and sustainable cities & communities (3) – cannot be achieved. Hence urban management has to focus on infrastructure supporting people’s well-being.

Positive impact of green area on mental and physical health (4)

Studies in China by B. Jiang et al. evinced interesting results that are discussed in the following. Living in an urban environment can be stressful and unhealthy. The researchers showed that life in a city brings stress, pressure and distance to nature and that these factors can lead to psychological trouble. This produces on one hand mental and social problems such as suicide and violent crimes. One the other hand serious health problems such as cardiovascular diseases and diabetes can result. Furthermore, stress and mental trouble are known to trigger an unhealthy lifestyle, including less physical activity and an increased consumption of addictive substances such as cigarettes, drugs and alcohol. One apparent effect thereof is obesity which is monitored to be increasing. A further negative impact that life in cities has on human health is the pollution load.

According to B. Jiang et al. there are five benefits of urban green area on people’s health and well-being: green landscapes promote physical exercise, they relieve stress, they reduce mental fatigue, they provide ecological products or services and they improve social capital. These mechanisms and their impacts can be seen in figure 1. Moreover, they are further explained in the text below.

Fig. 1: Theoretical framework: mechanisms of impacts of urban green landscapes on public Health (4)

A green environment with vegetation is much more stimulating for doing sports than the typically grey and unnatural urban surrounding. That is why people tend to move more and longer, what does not only improve physical health but also cognitive functions and mental fitness, e.g. by positive emotions. Furthermore, it was shown that exercises in green area also have a positive impact on the immune system as the production of killer cells and anti-cancer active proteins is supported and as the level of adrenaline is minimized.

Green area is a good place to mentally recover. Already in 1991 researchers found that being in a green and natural surrounding can affect positively the psychological processing of stressful experiences. Indicators therefor are physical ones such as heart rate, skin contraction level, cortisol level and blood pressure as well as mental ones, specifically levels of optimistic emotions and anxiety. Studies could quantify this effect by a three times better stress relief in presence of vegetation (30% canopy cover), compared to an urban surrounding without any natural structures. This fact has got a particular importance in the environment of schools and hospitals. There are several indicators such as blood pressure, duration of the stay, required medicine and positive emotions clarifying the benefits of vegetation around hospitals.

A natural surrounding does not demand as much concentration as an urban one since it is much calmer and there are less stimuli. That is why green area is recognized as a helpful place to restore human cognitive abilities, namely capacities to concentrate and to pay attention. Again, there is a special interest to have green environment at school sites. It was shown that students could do better in school if there were natural surroundings.

Next to direct impacts on health there are also long-term benefits for humankind. Green landscapes help reduce the load of greenhouse gases and minimize the island heat effect. This is especially important considering the fact temperatures on earth are still increasing. In addition, the existing green environment motivates people to do their own urban gardening. This does not only augment the positive impact on climate and health due to the reduction of air pollution and temperatures but also supports people’s consumption of fresh and healthy products.

The presence of green area also fosters social contacts. It offers an ideal place to meet other people, both spontaneously and arranged. Researchers found that due to the arising contacts so-called social ties are built. Furthermore, it could be shown that there are less crimes in areas with more vegetation. The overall effect of the expanded and stronger social contacts is an increased social capital.

Current efforts towards greener cities

There are many diverse reasons for green space in cities as shown above. Fortunately, it does not stay with theorical approaches. Every year since 2010 the European Commission awards a city for its outstanding efforts in sustainability. These cities are flagships for many other towns, regions and villages which are actively engaged in becoming greener. Winner of 2021 is the Finnish city of Lahti which was chosen because of its exemplary behavior in the domains of air quality, waste, green growth, eco-innovation and governance. In the winner press release the presence of green area is explicitly listed as one of the outstanding points: “In Lahti, 99% of people live within 300 metres of green urban areas. The city enables its inhabitants to enjoy nature in many different ways, offering leisure activities such as skiing, fishing and wild berry and mushroom picking.”. The prominent statement clarifies once more the important role of the enclosure of green landscapes in cities. (5)

Another example for a development towards greener cities is the increasing number of Swiss citizens doing urban gardening. People seem to demand for green space, and they seem to enjoy the advantages that are offered by shared gardens. As mentioned in the text above they can directly benefit from urban gardening due to home-grown fruits, berries and vegetables, social contacts, physical exercise and a relieving environment. The trend is currently increasing further because people seek even more for these aspects in times of Covid19. However, the movement, that started in 2012, appears to be more than a short-term hype. The city of Bern realized the request and tries to provide more public space. Thus it took a step further towards a sustainable and green city. (6)

To conclude it can be said that there are several attempts all over the world aiming more green area in cities, both on a governmental and a population level. On one hand researchers could prove the positive impact of green space on human health and well-being as well as on climate. On the other hand – and this might be even more important – people seem to have an intrinsic motivation to keep or build natural structures in their urban surroundings. They actually demand for it. And both sides together – scientific research and people’s behavior – will hopefully further promote a development towards a more active green urban planning. This is absolutely in need as green spaces increase the value of a city. They improve human fitness, they minimize stress, they enhance concentration, they reduce greenhouse gas effect, they extend social networks, they mitigate pollution and noise load, they lift up emotions, they provide fresh food and they simply give pleasure. These factors are valid for everyone, but they seem to be even more important for people with impairment, children and elderly people. And of course, the positive impacts gain anymore meaningfulness in consideration of the increasing population and the urbanization. More and more people live in urban areas. Therefore, cities are required to be sustainable and worth to live in. And worth living cities include enough green space.

References:

1. Bundesamt für Naturschutz (BfN). Städtische Grünflächen : Eine Handlungsanleitung. 2018.
2. Taubenböck H. WM. Globale Urbanisierung. Springer Berlin Heidelberg; 2015. doi:10.1007/978-3-662-44841-0
3. UN Desa. Sustainable Development Goals: Knowledge Platform. https://sustainabledevelopment.un.org/?menu=1300. Accessed May 3, 2020.
4. Jiang B, Zhang T, Sullivan W. Healthy Cities: Mechanisms and research questions regarding the impacts of urban green landscapes on public health and well-being. Landsc Archit Front. 2015;3:24-35. doi:10.1007/slaf-0024-0301-xx#1
5. EuropeanCommission. Press Release – Green City Awards Go to Lahti, Limerick and Mechelen!; 2019. http://ec.europa.eu/environment/europeangreencapital/europeangreenleaf/. Accessed May 4, 2020.
6. Schott Y. Das Coronavirus sorgt für einen Run auf Urban Gardening. Bärnerbär. https://baernerbaer.ch/baern/das-coronavirus-sorgt-fuer-einen-run-auf-urban-gardening/. Published 2020. Accessed May 4, 2020.