Implementing an uncertainty-based risk conceptualisation in the context of environmental risk assessment, with emphasis on the bias of uncertain assumptions

ABSTRACT Environmental risk assessments are routinely carried out in the Norwegian petroleum industry. As this industry is moving north, towards the Arctic and into areas with differing vulnerabilities and new risk sources compared to the now well-developed areas, previous operational experience and analytical practice may become less relevant. Reflecting the lack of knowledge (i.e. the uncertainty) that exists, and the strength of the available knowledge, then becomes critical. In the present paper, we review and discuss the industry guideline that for a long time has formed the methodological basis for these assessments, focusing on its foundation concerning risk and uncertainty. We conclude that there is a potential for improvement, and to contribute to improving the guideline, we describe how to implement – in the context of environmental risk assessment – a framework for conceptualising risk and its description that is consistent with the new uncertainty-based risk perspective recently adopted by the Petroleum Safety Authority Norway and in the Society for Risk Analysis glossary. The implementation includes a description and exemplification of a method for assessing the bias of uncertain risk assessment assumptions.