Glacier Loss and Climate Change in Southwest Greenland: Long-term Perspectives from Lake Sediments

Climate is warming faster over the arctic than any other region on earth. These changes have global consequences, most notably via the accelerating loss of ice from the Greenland Ice Sheet, one of the largest sources of future sea level rise. Despite Greenland’s global importance, direct observations of its climate and environment date back only a few decades, leaving open the question of how unusual current changes in Greenland really are. For example, mountain glaciers and ice caps in the proposed study area appear to be in a state of retreat that suggests they will disappear if present-day climate conditions continue. Are these threatened glaciers long-lived features of Greenland’s landscape, making their imminent disappearance unprecedented over millennia? Or are they short-lived, transient features that date back only a few centuries into the recent Little Ice Age? Similarly, few quantitative temperature reconstructions exist for Greenland beyond those inferred from the ice sheet itself, leaving many questions about Greenland’s long-term temperature history unanswered. The proposed study aims to address these unknowns, and to place recent climate change in a long-term context, by reconstructing mountain glacier fluctuations and accompanying temperature changes in southwest Greenland over the past several thousand years (the late Holocene epoch). Sediment cores will be obtained from remote glacial and non-glacial lakes south of Nuuk. The investigators will use preserved temperature-sensitive insect species to reconstruct temperatures through the late Holocene, and will examine the sediments of neighboring glacier-fed lakes to reconstruct the history of the region’s threatened mountain glaciers.