Will an increased greenhouse impact in Fennoscandia give rise to more humic and coloured lakes ?

Increased discharges of humic material during the 1970s and 1980s had contributed to the increase in colour in Swedish surface waters. Although increased precipitation was the major cause of the changes, up to 40 per cent of the increase in river transport of coloured material was independent of discharge. Factors potentially responsible for the increase included higher groundwater levels in direct contact with organic soils, the contribution of iron compounds and reduced capacity of soils to absorb organic matter due to acidification. The possibility that large-scale changes in humus flux might be strengthened by global warming is considered.