Here we combine new and novel data sources to estimate the availability of green spaces in 5 625 urban agglomerations with 10 000 inhabitants and above. The rest of the report then uses this novel dataset to first evaluate the dynamics between urbanisation and green spaces, and second, explore the potential of green spaces to boost the resilience and sustainability of cities in the future. The results show that as urban agglomerations become larger and more compact, green spaces disappear, exacerbating their vulnerability to climate change and deteriorating liveability. However, building taller buildings (i.e., growing vertically), offers a way for cities to grow whilst minimising the loss of green space. Results show that more green space can boost sustainability by significantly lowering air pollution in African cities, which could be vital for public health in the future since outdoor air pollution is rising. The potential for green spaces to enhance resilience to climate events, like heat waves, depends on the location of green spaces throughout the city and the percentage of the population that lives close to a green space (i.e., within 300 metres).