Shortlisted for the Southwood Prize 2022
This post is also available in Brazilian Portuguese here.
Douglas Cirino discusses his and research colleagues’ article which explores how healthier urban landscapes are those that share city space with greenery.
São Paulo
Upon arriving in São Paulo, the largest metropolis in the world outside of Asia, I was shocked by the amount of concrete used to build the city. As a child sitting in the passenger seat of my father’s truck, which was slightly elevated above the ground level of the cars, I could clearly see an infinite number of buildings rising up from an endless amount of asphalt on a central eight-lane road. Everything seemed so massive that I barely noticed the tree lines alongside the polluted and garbage-filled river meeting another equally large and dirty river.
This is probably the image that millions of people who have arrived in São Paulo in the last seven or eight years have in mind, and it is likely the image that millions of others who have never been to the city have in their subconscious.
About ten years later, while living in São Paulo and taking off from the airport in the middle of the city, I had the same impression of the vastness of the city, but at the same time, I appreciated the balance between total chaos and natural self-organization, like a fungus colony, a buzzing site, or a termite nest. At that time, I noticed how some patches of green remained in the middle of the city, and how many streets and backyards were aligned with small amounts of vegetation.
Sharing and sparing
As a first-year undergraduate student, I could not have known that this pattern of land sharing and sparing between the city and green areas would become my research area and daily subject of work.
This pattern actually came from a landscape ecology perspective, which was first applied to crop yield and biodiversity conservation, and was later discussed in the strategies for growing modern cities around the world. The sparing is represented by delimited patches of green in the middle or borders of the city, like parks or natural remnants, separating green and grey. On the other hand, sharing is represented by the mixture of the constructed environment and small spots of green between buildings and city facilities.
When I first saw São Paulo from above, I sincerely hated the big city with all its grey, noise, and pollution. I was born and raised in the countryside, playing on my grandparent’s farm. I love biology and ecology, and studying in such a city made me depressed for some years. This scene shifted completely more than ten years later. Nowadays, I appreciate São Paulo and its complexity more than any other city in the world, and the health issues I faced made me question the relation between green in the city and people’s well-being.
The research
In my research, we found that the distribution of green across the city matters much more than the total amount of green. Adapting and measuring the land-sharing-sparing approach for the city, we related the hospitalization of São Paulo’s residents to the level of segregation and mixture between grey and green, controlling social variations.
We found that higher levels of land sharing – having green spaces between households, street afforestation, and small green patches – decreases, on average, 8% of the rates of cardiovascular diseases for each 10% of sharing level increment. For pulmonary diseases, neighbourhoods with a balance between sharing and sparing, with isolated trees and small urban forests, showed a significant decrease in hospitalization rates. Each 10% of this type of green coverage increment decreased the hospitalization rate by 17%.
The prevailing theory to explain these patterns is the offer of ecosystem services in the city, given by green areas, since cultural and regulatory ecosystem services are known to impact human welfare. Our main hypothesis is that this kind of sharing green and grey distribution seems to be key to understanding the connection between people and nature, with daily contact with natural attributes having a central role in the control of diseases.
The sharing-sparing pattern can be observed in many urban areas throughout the world, in a range of city sizes and levels of greenery, as well as the variation in disease occurrence between different neighbourhoods with different social characteristics and access to ecosystem services. Understand those spatial distributions and patterns could be a starting point for city policies and solutions based on nature to create more sustainable and equitable cities.
About the author
I myself began “sharing” the city with greenery when I moved to a more land sharing neighbourhood. I now proudly cultivate a private tropical garden in my backyard and have felt my health and quality of life increase with daily contact with nature.
This situation even inspired me to continue my research, now in my PhD, investigating and mapping the provision of ecosystem services in the city on a finer scale, taking into account people’s perceptions and experiences with greenery to understand their relation with the improvement in health. One of my main questions at the moment is whether moving to a neighbourhood with more ecosystem services could increase human health.
Recreational use and scenic appreciation of urban greenery may be a key to rethinking life in large urban centres. One of my main recreational activities involves cycling in a linear park alongside one of the rivers I described at the beginning of the text, which is currently undergoing total depollution and revitalization, demonstrating the recognition of cities in providing green services to the population.
Read the full article, “Balanced spatial distribution of green areas creates healthier urban landscapes” in Journal of Applied Ecology.
Find the other early career researchers and their articles that have been shortlisted for the 2022 Southwood Prize here!
