Concern about the state of the natural environment has deep historical roots, but the nature and scale of concerns, and their political importance, has grown and changed considerably since the wave of environmental protests which swept across developed countries during the 1960s. 1 These debates were directed primarily at local and occasionally regional problems; none appeared to exist at the global level. The lead issues primarily concerned toxic and chemical pollution, such as pesticides, issues which helped to launch the modern environmental movements. 2 Other local problems, such as urban air pollution, were often addressed either by technical fixes to clean up emissions and where necessary dump the residues, or by transferring pollutants into less critical environmental media or by spreading them over a wider area (eg. the ‘high chimney policy’ adopted to disperse stack emissions). Regulations for some environmental media were developed, but different areas were generally considered separately with little attention paid to their interrelation and interaction. Many years later, limitations to waste dumping, and the potentially devastating effects of the steady accumulation of pollutants in the biosphere became recognised, eg. the acidification of woodlands and lakes, and development of the Antarctic ‘ozone hole’ and broader ozone depletion. 3