Seminar Abstract

Stewart Cohen

Tuesday, November 4, 2008

Moving beyond the damage report: Adapting to climate change in the Okanagan region, British Columbia

Climate change impacts research provides an approach to describe potential changes in risk for individual watersheds, thereby offering a way for incorporating future climate change scenarios into long-range planning and management. This process could be enhanced using participatory approaches which combine research and practitioner knowledge to determine impacts on specific aspects of water systems, and to assess the effectiveness of adaptation measures on these systems.

This participatory assessment method was used in a case study of the Okanagan region of British Columbia. Climate change scenarios were used as inputs to a number of other tools for projecting impacts on hydrology, water supply, agricultural water demand, and residential water demand. These impacts scenarios, combined with system information on managed supply and in-stream flows, provided the basis for embarking on a group-based model building exercise with local water practitioners. The software used in the construction of this model was the stock and flow STELLA™ software.

The first scenario tested, based on the HadCM3 A2 (high emissions) climate scenario, combined with a range of population growth scenarios, showed that without interventions, regional water demands would not be met in the future. Demand would exceed supply by the 2050s, and as early as the 2020s in relatively dry years. Aggressive implementation of residential conservation measures could reduce total demand in the 2050's, but this would not be enough on its own to offset the supply-demand gap. Supplemental use of Okanagan Lake would be of benefit to meeting future agricultural and residential user demands. However, system performance for meeting future instream flow requirements would deteriorate, and Okanagan Lake levels would decline. This indicates that on its own, additional withdrawal from Okanagan Lake would lead to mining of the lake and increased risks to aquatic ecosystems. This does not mean that supplemental use of the lake should be rejected as a possible adaptation option. If used in conjunction with demand side management, overall system performance could improve. However, this would be a more complex portfolio to manage.

In the search for the ‘best' adaptation portfolio for the Okanagan water system as a whole, the water system design process will need to consider both local and basin-scale dimensions, as well as external drivers influencing individual and community choices. This means that in order to adapt to climate change, planning for climate change will need to be more closely integrated with long term community and regional development planning. We need to ask questions about the potential effects of development paths themselves on the water balance of the 2050s and beyond. What new risks and opportunities may emerge from these? Moving beyond the climate change damage report requires an approach that explicitly integrates climate change response and sustainable development initiatives.

Speaker bio:

Dr. Stewart J. Cohen is senior researcher with the Adaptation and Impacts Research Division of Environment Canada, and an Adjunct Professor with the Department of Forest Resources Management of the University of British Columbia (UBC). Dr. Cohen's research interests are in climate change impacts and adaptation at the regional scale, and exploring how climate change can affect sustainable development. Recent work includes a case study on climate change and water management in the Okanagan region of British Columbia , and the study on climate change visualization led by Professor Stephen Sheppard of UBC. He is currently a member of the advisory committee for the Columbia Basin Trust climate change adaptation program. Previously, he led the Mackenzie Basin Impact Study (MBIS), a 7-year effort focused on climate change impacts in the western Canadian Arctic, completed in 1997. His earlier work included research on impacts in the Great Lakes and Saskatchewan River Basins . He has been a Lead Author for the Intergovernmental Panel on Climate Change (IPCC) Third and Fourth Assessment Reports and has contributed to other IPCC documents and technical workshops since 1992. Dr. Cohen is a geographer having received his B.Sc., M.Sc. and Ph.D. from McGill University , University of Alberta , and University of Illinois , respectively.