Abdulhakim M Abdi

The human-environment connection in the mostly rural drylands of Africa forms a complex, interlinked system that provides ecosystem services. This system is susceptible to climatic variability that impacts the supply of its products, and high population growth, which impacts the demand for these products. When plants remove carbon dioxide from the atmosphere through the process of photosynthesis, they use some of this carbon to maintain plant cellular structure. The rest is stored as plant tissue and forms plant biomass. The annual accumulation of this plant biomass is called net primary production (NPP). On an annual basis, NPP supplies the provision of crops, animal feed and pasture. The societal implications of reduced NPP can be severe, possibly leading to crop failure and eventual food insecurity. This paper focuses on a method of quantifying the human impact on ecosystems using satellite-derived estimates of NPP and quantitative data on the demand for food, feed, and fuel. This work leans on three main sources (see footnote) and streamlines key concepts introduced therein. The first section is an introduction to the link between humans and the environment in the drylands of Africa. The second section describes the role of climate and the concept of primary production, and the history of its estimation using data from Earth-observing satellites. The third section presents the various consumable components necessary for human survival and their statistical derivation. The fourth section details the conceptual framework that is based on the supply and demand of NPP. The fifth section broadly discusses the framework’s advantages and limitations, other studies that attempt to quantify human impact on ecosystems as well as knowledge gaps and future research needs.