| Summary: | Arctic sea ice is rapidly declining in area and volume, with impacts on local and global climatic and ecological conditions. Without knowledge of past changes, this modern trend cannot be placed within a broader context that would aid future predictions for Arctic sea ice. Driftwood forms an under-utilised proxy for reconstructing Arctic sea ice extent over the Holocene (~12,000 yrs ago to present): its transport and deposition is determined by sea ice and surface current dynamics; making it a robust proxy for sea ice reconstructions. Driftwood in the Arctic results from the falling of trees into the large rivers that drain the circum-Arctic, which upon flowing into the Arctic Ocean can then become locked up in forming sea ice. This enables the driftwood to travel across the Arctic Ocean without sinking, making it an invaluable proxy for sea ice extent by recording variations in Arctic Ocean surface currents (and therefore sea ice drift) and ice cover. Given it takes on average multiple years for driftwood to travel from origin to destination in a high Arctic beach, multi-year sea ice is required for its transport. Driftwood is abundant on many raised Arctic beaches, as it is captured on shorelines that have risen out of the sea due to the retreat of the weight of glaciers at the end of the last ice age. Analysis of the driftwood’s age and provenance can be used to form a reconstruction of the driftwood transport routes through time, and therefore Arctic sea ice extent and dynamics. I present a first pan-Arctic collation of Holocene driftwood data providing a reconstruction of higher spatial and temporal resolution than other proxy-based methods. The collation of 913 driftwood samples from across the western Arctic with spatiotemporal distribution and available provenance data enabled the production of a proxy-based reconstruction of Holocene Arctic Ocean surface current and sea ice dynamics. This revealed that Holocene sea ice extent and drift is characterised by a gradual progression from millennial to ...
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