The snow that fell last year - was it the last? Snow cover as an indicator of climate change

Summary

Transient changes in snow cover depth and duration have been simulated for several small catchments in different altitude zones in south-western Norway, based on dynamically downscaled data from the ECHAM4/OPYC3 Atmosphere-Ocean General Circulation Model run with the IS92a emission scenario. The HBV model has been used for simulation of snow cover, and the runs cover the period up to the middle of this century. The results are less clear-cut than could be expected, especially at low and intermediate altitudes, where “normal” variability to a large extent masks the climate change signal. As snow cover is a very visible climatic indicator, and the Nordic public relates strongly to it, it has the potential to convey strong messages about climatic change. These messages may however in practice be quite confusing. Implications of this and lessons about how to communicate climate change to the public are discussed.