INTRODUCTION

The protection of the atmosphere was a relative latecomer to international environmental regulation but is now well established. With limited exceptions, until 1979 no treaty sought, as its primary purpose, to place limits on the right of states to allow atmospheric emissions that caused environmental damage. Some treaties had, however, called for general preventive strategies. Since 1979, numerous treaties and other international acts have addressed the protection of the atmosphere. Although there is no atmospheric equivalent to the 1982 UN Convention on the Law of the Sea, international legal instruments have been adopted at the regional and global level which address a range of issues, including: transboundary pollution by sulphur dioxide, nitrogen oxide, volatile organic compounds, heavy metals and persistent organic pollutants (POPs); the protection of the ozone layer; the prevention of climate change; and the protection of the environment of outer space. The precedents set by treaties relating to the protection of other environmental media, in particular the marine environment, have contributed to the development of these rules.

Landmarks in the development of international law in this area include: the 1938 and 1941 decisions in the Trail Smelter case; the applications brought to the ICJ by Australia and New Zealand against France with respect to French atmospheric nuclear tests in the Pacific Ocean region; growing evidence in Europe and North America in the 1970s of acid rain damage from atmospheric emissions of sulphur compounds; the 1986 Chernobyl accident; growing evidence in the 1980s of depletion of the ozone layer; greater awareness of the threats posed by forest fires with transnational effects, such as those in Indonesia in 1997 which caused widespread regional problems, and, mostly recently, consolidation of scientific evidence that increased atmospheric concentrations of carbon dioxide and other greenhouse gases are likely to cause temperatures to increase worldwide with consequential adverse effects.