An environmental risk assessment/management framework for climate change impact assessments

This paper presents an environmental risk assessment/risk management framework to assess the impacts of climate change on individual exposure units identified as potentially vulnerable to climate change. This framework is designed specifically to manage the systematic uncertainties that accompany the propagation of climate change scenarios through a sequence of biophysical and socio-economic climate impacts. Risk analysis methods consistent with the IPCC Technical Guidelines for Assessing Climate Change Impacts and Adaptations are set within a larger framework that involves stakeholders in the identification, assessment and implementation of adaptation measures. Extensive consultation between parties occurs in a flexible structure that embeds scientific methods of risk analysis within a broad setting of social decision-making. This format is consistent with recent forms of environmental risk assessment/management frameworks. The risk analysis links key climatic variables expressed as projected ranges of climate change with an upper and lower limit, with impact thresholds identified collaboratively by researchers and stakeholders. The conditional probabilities of exceeding these thresholds are then assessed (probabilities using this method are conditional as the full range of uncertainty for the various drivers of climate change, and their probability distributions, remains unknown). An example based on exceeding irrigation demand limited by an annual farm cap is used to show how conditional probabilities for the exceedance of a critical threshold can be used to assess the need for adaptation. The time between the identification of an acceptable level of risk and its exceedance is identified as a window of adaptation. The treatment of risk consists of two complementary actions, adaptation to anticipated changes in climate and the mitigation of climate change through reductions in greenhouse gas emissions. Both of these actions will reduce the risk of critical thresholds being exceeded. The potential of this framework for addressing specific requirements of the United Nations Framework Convention for Climate Change is discussed.