INFLUENCE OF CLIMATIC AND ANTHROPOGENIC FACTORS ON THE WHITE SEA – CATCHMENT SYSTEM

Abstract

Variability of the regional climate is investigated, and its impact on river runoff and some economic processes in the catchment, including fisheries – one of the main livelihoods of the local population – is evaluated. Warming of the regional climate over the past 60 years has not led to any tangible change in mean annual river runoff (no significant trend observed), but was evident in the increase of the water temperature in rivers and the White Sea. The greatest temperature increase is typical for winter months, especially January (mean values over 1991–2017 exceed the climatic norms by 1.7–2.5 °С). The change in flow over the past decades (since 1997) as compared to the preceding period is multidirectional and not significant. During the maximal climate warming in the catchment in 1987–2015, total river runoff varied within 200–310 km3/yr, the average over this period being ca. 230 km3/yr. The water temperature in rivers in the catchment has increased since the mid-1980’s by an average of 1 °С; these variations are coherent to air temperature fluctuations over the catchments of the respective rivers. The observed excessive summer heating of the White Sea under climate warming unfavorably affects the productivity of herring and navaga, fish of the Arctic origin. Since the 1990’s, ecological parameters such as atmospheric emissions and effluent discharges have changed for the better because of the regional economy decline, and since the 2000’s – owing to changes in the structure of the economy and investments in technological upgrade and nature conservation measures.