PS 48-256 - Scaling global urban greenspace

Abstract: Cites are novel ecosystems. Understanding the complex interactions between urban abiotic and biotic attributes is important for managing future urban expansion. Using urban scaling theory (UST) combined with global datasets raises the prospect of deriving predictive rules for scaling urban greenspace with city size. Aspects of the city, such as greenspace, are influenced by several social and ecological factors that scale with a city's size. Empirical data from European cities showed superlinear scaling, in which greenspace increased disproportionately with city size. However, the comprehension of global greenspace scaling still needs to be understood. A macroecological perspective using a scaling approach is needed to understand how urban environments function on broader spatial scales. We aim to develop predictive measures of how urban greenspace scales with various attributes by answering the following question: i) How does greenspace scale with city size and population globally? Our study is a first look at global greenspace scaling, providing statistical information about how greenspace is changing with city size globally. In this study, we use an open-access database called the Global Human Settlement Layer (GHSL) to analyze greenspace, population, and area in cities around the world. Using Rstudio and data from the GHSL, we examine the scaling properties of greenspace globally.

We evaluated the global greenspace area in cities using three attributes: built-up area, total urban area, and population. First, our results show superlinear scaling for greenspace against the built urban area for 4 countries out of 18 (China, Iran, Mexico, and Ukraine). Secondly, our results also show superlinear scaling for greenspace against the total urban area for 6 countries out of 19 (Bangladesh, China, Iran, Japan, Mexico, Russia, and Ukraine). Lastly, our results show that greenspace in all 19 countries scales superlinearly with population size. These results show that European cities show isometric scaling when greenspace is compared to a city's built and total urban area instead of the proposed superlinear scaling previously published. We present information for city planners to look beyond the scope of the Global North when thinking about greenspace in cities. Our next steps are to 1) explain the relationship between global urban greenspace, population density, and city size at the country level and 2) describe if there is a trade-off between greenspace and population density in cities globally. As the number of inhabitants continues to grow globally, this research is imperative to understanding the city as a living ecosystem.