The benefits of greenery in cities are plentiful, both environmental as well as social and health-related, from lowering temperatures to creating meeting spaces, which is why we should have more trees, more gardens and more parks in our cities.
The summer of 2022 was one of the hottest in many countries across Europe and the world: the UK exceeded 40 degrees for the first time ever; in Italy in July, it was 2.26 degrees above the average for the last thirty years, whereas the US has experienced its hottest nights in the last 150 years, since the data began to be collected. These extreme heat waves, the drought and bush fires have once again made it abundantly clear that we are already experiencing the devastating effects of the climate crisis and urban areas even became hostile to life on some days. In order to counter this emergency (which is just going to get worse), there is a need for mitigation (reduction of emissions) and adaptation at a profound and global level, but in the meantime urban greenery can be a great help - especially in the cities. Its benefits are not only environmental and climatic, but also social, health-related and psychological.
The environmental benefits of urban greenery
The positive aspects of urban greenery in terms of climate and the environment are the most well-known and obvious. In the piece of research The role of urban trees in reducing land surface temperatures in European cities which was published last year in Nature communications, a team of scientists measured the earth's surface temperature (using high-definition satellite data) in 293 European cities, to assess the link between the presence of trees and the drop in temperature. Well, compared to the areas where there are buildings and factories, in those where there are trees, the temperature in the summer falls between 0 and 4 degrees in southern Europe and even between 8 and 12 degrees in central Europe.
It should also be remembered that trees are extraordinary traps for carbon dioxide, one of the principal greenhouse gases responsible for the climate crisis. Urban greenery in the form of roof gardens on buildings and private houses can improve their insulation, allowing energy savings of between 10% and 25% depending on the season. Trees also lower noise pollution (reducing the reflection of sound in cities).
The social and health benefits
Cecil Konijnendijk, the co-founder of the Nature based solutions institute, created the 3-30-300 formula, according to which each person should be able to see at least 3 trees from their home, there should be 30 percent tree cover in each neighbourhood, and 300 metres is the maximum distance between each house and a public green space (this latter dimension is also recommended by the World Health Organization).
As a matter of fact, as stated by the European Environment Agency, parks, urban forests, gardens, tree-lined avenues and river banks support the well-being of the city by providing people with space to relax, play sports and socialise. Green spaces must increase in cities and must be well maintained, because only then can they be transformed into lively locations that are crucial to a better city life.
To mention another piece of research, Social benefits of urban green space, “the social benefits of urban greenery include recreational opportunities, entertainment, improved psychological well-being and physical health, increased social ties and educational opportunities”.
