The question of global sustainability is concerned with the nature of the environment-human relationship. However, evaluations of global sustainability have been based predominantly on subjective or professional judgement. In this paper, a mathematical model is applied to the data of the 2004 Environmental Vulnerability Index (EVI) conducted by SOPAC to obtain indicative weighted levels of ecological sustainability (SEc) at the global level. The paper uses and evaluates the results obtained within the context of four influencing factors: population size, population density, GDP and Human Development Index (HDI). The paper also determines whether there is a statistical relationship between SEc-levels and each of the influencing factors. The results highlight a significant quantitative and statistical relationship between population density and obtained levels of SEc, as well as a relationship between GDP and SEc. Furthermore, while HDI and SEc produced a non-statistical curvilinear relationship, it is suggested that this may be indicative of a 'tipping point' scenario as countries develop socioeconomically to the detriment of the environment and consequently sustainability. Based on the mean average of obtained weighted values of global SEc, the indicated global SEc-value is in the range of 0.261-0.299 with an error of ±0.060-0.094, indicating weak sustainability, depending on the inclusion of the most significant or all of the influencing factors evaluated.