The literatures and debates on human development on the one hand and sustainability on the other share much in common. Human development is essentially what sustainability advocates want to sustain and without sustainability, human development is not true human development. Yet the two strands of research have largely been separate and this paper shows how they can learn from each other. I put forward a concrete proposal on how human development and its measurement in the form of the Human Development Index (HDI) can be linked with measures of both weak and strong sustainability. Weak sustainability is built on the assumption that different forms of capital are substitutable, whereas strong sustainability rejects the notion of substitutability for certain critical forms of natural capital. Empirical results over the period 1980 to 2006 show that many of the lowest performing countries on the HDI also face problems of weak unsustainability, as measured by genuine savings. Countries with high to very high HDI performance, on the other hand, typically appear to be strongly unsustainable, as measured by ecological footprints, mostly because of unsustainably large carbon dioxide emissions. Two of the biggest challenges facing mankind this century will be to break the link between high human development and strongly unsustainable damage to natural capital on the one hand, requiring a very significant and rapid decarbonisation of their economies, and assisting countries with very low human development to overcome weak unsustainability by raising their investment levels into all forms of capital on the other.
