The role of climate in settlement and landscape change in the north Atlantic islands:: An assessment of cumulative deviations in high-resolution proxy climate records

In order to assess possible contributions of climate change to the human ecology of the North Atlantic islands we evaluate the utility of cumulative deviations from the mean, calculated for the Greenland ice core storm frequency proxy (GISP2 Na+) and sea ice proxy (GISP2 chloride excess). Our aim is to identify episodes of unpredictable change in the context of long-term trends of cultural and environmental development. Key changes are identified in the proxy climate records in 975 and 980 AD, 1025 and 1040 AD, 1180 AD, 1425 and 1450 AD, and 1520 and 1525 AD. Some of these changes are consistent with those inferred from new studies of the palaeoecological record of the Faroes. This indicates that the cumulative deviation measure could give greatest prominence to the most important climate changes affecting landscapes and settlement (such as the changes of 1425 and 1450 AD and their immediate aftermath), rather than extreme events, such as great single storms.