Ice Core Evidence of Regionalization of Holocene Climate in the Circum-Arctic Region

Comparison of high resolution Holocene glaciochemical ice core records recovered from the Penny Ice Cap, Baffin Island with those from Summit, Greenland reveal distinct differences that can be related to different source regions and/or transport distances. These records can therefore be used to investigate different aspects of the Arctic climate system. For example, the Penny sea-salt sodium records shows an overall decrease during the Little Ice Age due to an increase in sea ice extent in the nearby source regions in Baffin Bay and Davis Strait, while the GISP2 record shows an overall increase in sea-salt sodium related to an intensification of atmospheric circulation during cold periods. A new high resolution five thousand year glaciochemical record has been developed from the Devon Ice Cap in the eastern Canadian Arctic and is compared and contrasted with the Penny and Summit records. In addition to considerable decadal and century scale variability and a decrease in sea-salt concentrations during the Little Ice Age, the Devon and Penny sea-salt records also show a long-term decrease since the mid-Holocene, suggesting a long-term regional increase in sea ice extent. We also investigate dust deposition and recent anthropogenic signals at the three sites. We conclude that glaciochemical records developed from small ice caps throughout the circum-Arctic region provide valuable measures of regional-scale paleoenvironmental change that are critical for our understanding of the climate change in the region over the mid to late Holocene.