1. Arctic catastrophes: sea ice changes and impacts in the Eastern Arctic during the past 4,000 years Mudie, P.J. 1, Levac, E. 2, and Rochon, A. 3 1 Geological Survey Canada Atlantic, 2 St. Mary’s University, Halifax; 3 IFREMER, Rimouski SUMMARY Climate warming and reduction of sea ice in the last 30 years has forced major changes on the traditional way of living for Inuit people of the Eastern Canadian Arctic. Large breaks in archaeo- logical records also suggest that drastic climate changes forced abandonment of settlements and life style shifts in Paleo- and Neo- eskimo societies. However, the low, century-scale time resolution of these records does not allow testing of this hypothesis of climate-driven cultural changes (Mudie et al. 2005). In this study, we looked at decadal-scale paleoclimatic changes recorded by palynological data in unbroken 6,500 year records from Coburg Polynya near sites on the North Devon Lowlands (Panel A), and from the North Water Polynya near S.E. Ellesmere Island (Panel B). Paleotransfer function data from dinoflagellate cyst assemblages provide estimates of changes in surface temperature (SST) and sea ice cover (SIC) with a precision of +/- 1C and 1 month, respectively. The proxy-data for both marine sites show that abrupt temperature changes of 2 – 4 o C correspond to major shifts in hunting modes of Paleo- and Neo-Eskimo peoples and to occupation-abandonment cycles recorded for Devon and Ellesmere Islands by Helmer (1991; 1992) and Schledermann (1990). From ~6500 to 2600 BP, there were large swings in summer SST from 2-4 o C cooler than now to 6 o C warmer. Annual variations in SIC ranged from times of a 2-month longer pack ice season to intervals with a 4-month longer open water season. The warmer times were when the pre-Dorset Palaeoeskimos hunted mostly land animals: muskox, caribou and fox. The switch to marine-based hunting (seal, whale, bear) by the later Dorset and Neo-Eskimo people corresponds to progressively cooler intervals with more sea ice. These past climate warming events took ~50-200 years to reach peak temperatures: this is only about half as fast as the current global warming. A) RESULTS: JONES SOUND-DEVON ISLAND CORE 6 B) RESULTS: NORTH WATER- ELLESMERE ISLAND Core 6 is from eastern Jones Sound, about 10 km SE of the northermost Inuit village at Grise Fiord (Fig. 1). Six AMS radiocarbon ages were used to date the 11 m core of marine mud. Abundant dinoflagellate cysts, the organic walled resting spores of phytoplankton and sea ice algae, were used to quantify past winter and summer temp- eratures (red fill), and amount of sea ice cover (blue fill), using the 607 coretop databases of Mudie and Rochon (2001) and De Vernal et al. (2001). Grey shading shows the intervals when summer temperatures were warmer than now, up to 6 o C. The green bars show occupation times of land-based hunters; blue bars show marine-based hunters. Fig. 1Fig. 2 Two cores were obtained from the North Water (Levac et al., 2001), about 50 km south of Alexandra Fiord, Bache Peninsula (Fig. 2). Nine radiocarbon ages were used to date the 8 meter-long section, and dinoflagellate cysts were used to reconstruct SST and SIC, as for Core 6 (see Panel A). Temperature changes at this more northern location are smaller than off Devon Island, but the alternating warmer and colder periods roughly coincide. In S.E. Ellesmere, however, we see slightly earlier evidence of the marine hunters (blue bars) and an earlier start of more severe sea ice conditions. REFERENCES: De Vernal et al., 2001. J. Quaternary Science 16: 681- 698; Helmer,,JW, 1991, Arctic 44:301-317; Ibid, 1992. J. Field Archaeology 19: 291- 313; Levac, E. et al., 2001. J. Quaternary Sci. 16:353-363; Mudie & Rochon, 2001. J. Quaternary Sci 16: 603-620; Mudie et al., 2005. Environmental Archaeology 10 (2); Schledermann, P., 1990. Crossroads to Greenland, AINA, Calgary, 364 pp. CONCLUSIONS: Forecasts of future Arctic climate change predict an increase of +4 to 6 ºC and summer open channels by year 2030 C.E., and there has already been a temperature rise of 1.5ºC in the past 30 years, while sea ice has shrunk by 14%. Some of the recent change is part of the natural long-term cycles that Arctic people have adapted to for 4,000 years. But the change is much faster now than the natural warming rate of 50-200 years, and the big question is “Can traditional hunting ways survive such rapid climate change?” Arctic dinoflagellates Location Map Study Areas