Sustainability and stability

There has been a burgeoning interest in the sustainability of many current trends – consumption, economic and demographic growth, and environmental change among them. While the origin of the term sustainable development is usually given as the report of the Brundtland Commission, Our Common Future (World Commission on Environment and Development 1987), its roots lie much deeper than that. One of the main precursors to the Brundtland Report, Herman Daly’s Towards a Steady State Economy (Daly 1973), directly appealed to John Stuart Mill’s mid-nineteenth-century thoughts on the stationary state. Mill saw a less growth-oriented strategy as the key to preserving at least some part of the natural environment (Mill 1909). Yet to do no more than maintain average incomes in many developing countries aggregate income is required to grow at rates up to 3.5 percent a year (i.e. to match the population growth rate), and increasing average incomes requires aggregate income to grow at rates above that. As Malthus had observed at the close of the eighteenth century, the consequences of failure to maintain average incomes have historically been severe (Malthus 1999). The challenge given to the global community by the Brundtland Commission was not just to avoid Malthusian crisis through the degradation of the resource base, but also to eliminate poverty worldwide.

The Brundtland definition of sustainable development – “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” – refers to the capacity of a system to maintain a flow of services over time (World Commission on Environment and Development 1987). This is a systems-level property that implies something both about system stability and about the value of system assets over time. What matters for the Brundtland definition is the capacity of the system to continue to deliver benefits over the expected range of environmental conditions.