Planetary boundaries: Using early warning signals for sustainable global governance

Over the past half-century, we have become adept at dealing with environmental problems at the local and regional scales. The worst excesses of the industrial revolution have, in many cases, been ameliorated. Rivers, such as the Thames in London, have been cleaned up and major urban air sheds, such as the Los Angeles basin, are now experiencing vastly improved air quality. DDT has been banned in most developed countries, and lead has been removed from petroleum-based fuels. These impressive successes have been celebrated in many quarters, perhaps most notably in Bjorn Lomborg’s book, The Sceptical Environmentalist (Lomborg, 2001). However, to say we have done enough globally would be false on two counts. Firstly, while these problems have been addressed in many European and North American nations, over three-quarters of the world’s people do not live in developed countries. For them, many of the local and regional environmental problems still exist and, in many cases, are worsening. Secondly, the environment – our life-support system – is under increasing threat from a wide range of human pressures, many of them emanating from high consumption levels in wealthy countries. The deterioration of the global environment puts even more pressure on the poorest countries to limit growth, even as they struggle to bring their populations out of poverty.