Leaf wax δH and varve-thickness climate proxies from proglacial lake sediments, Baffin Island, Arctic Canada.

We present a multiproxy paleoclimate record using leaf wax hydrogen isotopes (δH) and varve thickness from Arctic proglacial lake sediments. We also provide one of the first evaluations of the utility of δH as a paleoclimate proxy in Arctic proglacial lakes. We compare varve thickness and δH at sub-decadal resolution from 1948 to 2004 AD, and at sub-centennial resolution from 1450 to 2004 AD. Varve thickness and δH both contain large interannual variability and are anti-correlated during the late twentieth century, suggesting that both proxies respond rapidly, but by different mechanisms, to catchment-scale forcings. At longer time scales, varve thickness exhibits a strong response to Little Ice Age cooling (1661-1827 AD in this record) but does not show evidence for twentieth century warming recorded throughout the Arctic. δH does record regional-scale temperature changes, with more H-depleted values during the Little Ice Age and an abrupt change to more H-enriched values in the twentieth century. This corresponds well with a recent Arctic-wide temperature reconstruction in which the seventeenth century is the coldest interval, and the twentieth century is the warmest interval. Our results suggest that δH is a promising proxy that can be applied at high resolution in proglacial Arctic lakes. [ABSTRACT FROM AUTHOR]