NOAA/WDS Paleoclimatology - Lake N3, Greenland 7,800 Year Leaf Wax d2H and Geochemical Data

Precipitation is predicted to increase in the Arctic as temperature increases and sea ice retreats. Yet, the mechanisms controlling precipitation in the Arctic are poorly understood and quantified only by the short, sparse instrumental record. We use hydrogen isotope ratios (d2H) of lipid biomarkers in lake sediments from western Greenland to reconstruct precipitation seasonality and summer temperature during the past 8 kyr. Aquatic biomarker d2H was 100 per mil more negative from 6 to 4ka than during the early and late Holocene, which we interpret to reflect increased winter snowfall. The middle Holocene also had high summer air temperature, decreased early winter sea ice in Baffin Bay and the Labrador Sea, and a strong, warm West Greenland Current. These results corroborate model predictions of winter snowfall increases caused by sea ice retreat, and furthermore suggest that warm currents advecting more heat into the polar seas may enhance Arctic evaporation and snowfall.