Evidence from the Scandinavian Tree Line Since the Last Ice Age

The focus of this paper is to investigate the possible correlation between changes in the Scandinavian climate and solar activity. Information about climatic changes in Sweden and Norway has been obtained from three sources: the carbon-14 dating of pine wood retrieved from above the present pine tree limit, studies of glacial sediments and the carbon dating of alpine glacier moraines. Alpine tree limits reveal that summer temperatures in general were warmer during the millennia following the last ice age. Superimposed on this general trend are fluctuations of a few hundred years duration. A period probably as cold as the last several hundred years occurred around 8200 years ago. Other severe cooling took place around 4500,2200 and 1200 years ago. The timing of major climatic events has been compared with solar activity as measured by carbn-14 changes and shows a good correlation with cold periods in Scandinavia for most of the last 8000 years. Deviations between carbn-14 anomalies and the climatic record may be due to volcanic eruptions increasing the concentration of sulfate aerosols in the atmosphere.

A similarity between the periods of cold climate and carbon-14 levels indicates that solar variability may be an important factor for climate change.