Tracking the flow of ice in the Arctic is difficult. Reconstructing the extent and flow in times past is even more difficult. An interesting new report has turned to driftwood, embedded in the Arctic pack ice, as a way of deciphering Arctic climate conditions over the last 10,000 years. The researchers found a climate record that is in good agreement with previous histories, including such events as the Medieval Warm Period, the Little Ice Age and the Holocene Thermal Maximum. In fact, they found temperatures during the HTM to be 2° to 4°C higher than today. They also found a complementarity oscillation in sea-ice abundance between East and West that is not correctly simulated by current ice models.
Appearing in the August 5th, 2011, issue of Science, a report entitled “A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View from the Beach
” uses driftwood, originating in northern Asia and America, as an indicator of Arctic ice flows in times past. Svend Funder and colleagues analyzed samples of driftwood that accumulated on Greenland’s raised beaches and shores using the wood type and carbon dating. The voyage around the Arctic can take several years and can only occur when wood is incorporated in sea ice from the beginning with land fast ice preventing the wood from landing elsewhere. The driftwood in Greenland is therefore an indicator of multiyear pack ice.
“Our key to the mystery of the extent of sea ice during earlier epochs lies in the driftwood we found along the coast,” said team leader Sven Funder. “One might think that it had floated across sea, but such a journey takes several years, and driftwood would not be able to stay afloat for that long.”
Using this driftwood record, the researchers discovered a couple of interesting anomalies. Unsurprisingly, current ice models do not account for these new finds. The paper's abstract summarizes the results.