Trading urban green spaces for brown space development in African cities: evidence from the Greater Accra Metropolitan Area, Ghana

Africa is projected to experience rapid urbanisation in the next three decades. This therefore requires integration of green spaces to make urban areas liveable and sustainable. This paper analyzed the inter-decadal replacement of green spaces with brown spaces in the quest for urbanisation from 1991 to 2021 in Accra, Ghana. The support vector machine learning algorithm was used to classify Landsat satellite images into greens and browns representing vegetation and non-vegetation areas respectively. The post-classification pixel modelling was performed with 80-92% map accuracy. In 1991, green spaces covered 1135.09 km² while brown spaces constituted 367.36 km². Brown areas which constituted 24.5% in 1991 increased to 81% in 2021 while during the same period, green areas reduced their land area from 75.5% to 19%. The study recommends making people pay for the cost of brown spaces, introducing edible greens and supporting green politics as innovative ways to stop vegetation loss.