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

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.31 Geological Survey Canada Atlantic, 2 St.
Marys 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 4oC
  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 2-4oC cooler
  than now to 6oC 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.

Location Map
Study Areas

Arctic dinoflagellates

• B) RESULTS NORTH WATER- ELLESMERE ISLAND

A) RESULTS JONES SOUND-DEVON ISLAND CORE 6
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.
Fig. 1
Fig. 2
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 6oC. The green bars show
occupation times of land-based hunters blue bars
show marine-based hunters.
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?
REFERENCES De Vernal et al., 2001. J. Quaternary
Science 16 681-698 Helmer, ,JW, 1991, Arctic
44301-317 Ibid, 1992. J. Field Archaeology 19
291-313 Levac, E. et al., 2001. J. Quaternary
Sci. 16353-363 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.