Climate warming means that lowland lakes typically are experiencing longer ice-free periods, promoting greater biological productivity. However, despite this warming trend, biological productivity may be reduced, at least temporarily, in alpine areas with increased winter precipitation. During years with high winter precipitation in alpine areas of western Norway, in spite of higher temperatures, fish growth and recruitment were lower than in low-snowfall years. Annual fish growth rates were negatively correlated with spring snow depth – the greater the snow depth, the less the fish grew. During the years 1992 to 1995, a period with mean spring snow depth of 275 cm, fish growth was reduced by 50% compared to years with much less spring snow accumulation (1991 and 1996). A further increase in winter snowfall in these regions, as projected by climatic scenarios, would be expected to result in further reductions in biological production.
From collection: Global Outlook for Ice and Snow
Hugo Ahlenius, UNEP/GRID-Arendal