Determining the potential global sustainability outcomes of three Business-as-Usual scenarios 2016–2050 from a Doughnut model perspective

The Doughnut model of safe and just operating space (SJOS) has gained increasing prominence as a potential viable framework to foster sustainability. As a result, the Doughnut model has been the basis for the development of numerous new sustainability assessment frameworks. However, these frameworks have not thus far directly determined quantitatively the indicated level(s), nature, and dynamics of sustainability occurring. This is critical to address if the Doughnut model is to assist in fostering sustainability. Therefore, this paper develops and applies a new methodological approach, based upon the application of the Sustainability Dynamics Framework to a Doughnut-based SJOS assessment of three Business-as-Usual (BAU) scenarios (Lower, Middle, and Upper), at the global spatial scale for the period 2016–2050. The results obtained indicate very weak to weak unsustainability occurring in the Lower and Upper BAU scenarios (i.e., S(t) = +0.175 → −0.284 and S(t) = +0.135 → −0.064 respectively), and very weak sustainability trending towards unsustainability in the case of the Middle BAU scenario (i.e., S(t) = +0.151 → +0.115). However, the paper determines an outcome of potential significance. Specifically, these are the results of the Fourier analysis which obtained U-shaped t-plots for the Lower and Upper BAU scenarios. These t-plots are postulated as being the first quantitative indication of the process of systemic collapse occurring – societal in nature for the Lower BAU scenario, and environmental in nature for the Upper BAU scenario. The potential indication and risks of a systemic collapse occurring in the BAU scenarios reflects the perilous risks posed to humanity and the Earth System as a whole, if any of the BAU pathways continues to be followed.