1.2 Multidisciplinary nature
It is clear from the breadth of subject areas covered by international environmental law that, as a field of law it is inherently multidisciplinary. Decision-making on questions of international environmental law is usually influenced by various factors including scientific concepts, economic effects of decisions, and other moral and social imperatives. Increasingly, decision-makers and implementers of international environmental law are required to balance opposing interests in interpreting and applying international environmental legal norms. The Preamble of the United Nations Framework Convention on Climate Change (UNFCCC 1992), for example, recognises that, 'steps required to understand and address climate change will be environmentally, socially and economically most effective if they are based on relevant scientific, technical and economic considerations and continually re-evaluated in the light of new findings in these areas'.
International environmental treaties typically establish legal obligations on the basis of scientific evidence with varying degrees of uncertainty. The threshold of environmental harm is commonly undetermined or a matter of disagreement. For example, the USA and the European Union (EU) differ on restrictions to international trade of fish products or genetically treated beef products based on environmental and health grounds. The USA considers economic benefits and favours hard scientific evidence to justify such limitations on international trade. Conversely, the EU takes a precautionary position accommodating scientific uncertainties. Accordingly, scientific doubts justify banning the importation of hormone-treated beef from the United States to the EU in the Beef Hormones Case (WTO 1998).