ON SOLAR FORCING OF HOLOCENE CLIMATE - EVIDENCE FROM SCANDINAVIA

The focus of this study is the possible correlation between changes in the climate of Scandinavian and changes in solar irradiation. Reliabl e information about Holocene climatic change in Sweden and Norway is c urrently available from two main sources: the C-14 dating of pine wood retrieved from above the present pine-tree limit and studies of glaci er variations based on proglacial lacustrine sediments and on moraines . The reconstructed alpine tree-limit reveals that summer temperature in general was warmer during the early Holocene than it was during the late Holocene. Superimposed on this general trend are several fluctua tions of a few hundred years' duration. Relatively cold periods with a duration of the order of 300-600 years occurred frequently during the Holocene. In this paper, dates of the major climatic events are compa red with an index of solar activity, the so-called delta(14)C anomalie s. For most of the last 9000 years a good correspondence is demonstrat ed between the tinting of cold events in Scandinavia and the timing of major delta(14)C anomalies (low solar irradiation). The general Holoc ene cooling trend is believed to be partly a result of land uplift fol lowing deglaciation and partly a result of orbitally forced changes in irradiation. Large fluctuations in Scandinavian summer temperature ca n be reconciled with the pattern of climatic change presented in sever al recent studies in the North Atlantic region. A link between these a reas could be provided by changes in the production of North Atlantic Deep Water.