Assessing the Effects of Climate Change on Northern River Basins: Northern Watershed Ecosystem Response to Climate Change (North‐Watch) Workshop I: Climatic Drivers and Hydrological Regimes; Dorset, Ontario, Canada, 30 August to 3 September 2009

There is compelling evidence that climate change is affecting water resources in many parts of the world. Managing the societal consequences of this is one of the 21st century's major challenges to the prosperity and security of the international community. In few places will the changes and challenges be greater than in the boreal/subarctic region (defined broadly as the higher midlatitudes) of the Northern Hemisphere. In this circumpolar, transitional climatic zone, slight temperature differences determine the status of frozen ground, whether precipitation falls as rain or snow, and the degree to which winter snowpacks accumulate and subsequently melt.