The precautionary principle, often cited as one of the principles of sustainability, implies that decisions by governments, institutions and individuals need to allow for and recognize conditions of uncertainty, particularly with respect to the potential effect on the environment of policies and projects proposing physical development. The principle has been adopted in the Rio Declaration, in the EU's Environmental Action Plan, and in the UK in the government's Environmental Strategy and Sustainable Development Strategy.
However, there has been very little discussion of its application to such important policy areas as the future form of urban settlements, including the arguments around the compact city. There is, as yet, insufficient understanding of what is meant by the adoption of a precautionary stance, and how this is to be integrated into decision-making on development policies and projects. Various standards for risk assessment for nuclear facilities and for major accidents have been developed, but these may not be appropriate to other types of projects or policy areas, and in particular for the selection of alternative development or settlement patterns, or urban forms such as the compact city.
Moreover, there is evidence that there is considerable difference of opinion over the meaning of precaution between scientists, regulators, elected representatives and the general public. The furore caused by Greenpeace's opposition to Shell UK's proposed deep sea disposal of the Brent Spar North Sea oil platform confirms that scientific judgements of risk and uncertainty need to recognise the political dimension (in this case both international and national).
Major decisions need to be taken over the next few years, for example by the UK government for the accommodation of new households, in the light of household forecasts, and we therefore need to pay attention to what acting in a precautionary way might mean, and the different perceptions of decision-makers and potential residents. How far can we reach agreement over the risks associated with future forms of urban development?