Climate variability, climate change and the Australian snow season

Maximum winter snow depth at Spencers Creek in the Snowy Mountains of southeastern Australia has decreased somewhat since 1962, but the snow depth in spring has declined strongly (by about 40 per cent). The stronger decrease in spring snow depth is largely attributable to warming during July-September. The slight decline in precipitation that has been observed during this season is too weak to account for the decline in snow depth. Interannual variations in regional surface air pressure are closely related to snow depth, but there is only a weak trend in pressure and this trend is insufficient to account for the decline in spring snow depth. Thus the warming that is the proximate cause of the decline in spring snow depth is not simply reflecting a change in the synoptic patterns. In the light of recent studies implicating the enhanced greenhouse effect in the warming trend over Australia, the results of this study suggest that the Australian alpine region may already be experiencing significant effects of greenhouse climate change.