Surface Mass Balance of the Greenland Ice Sheet

This research aims to quantify changes in snowfall, temperature, snow density, surface melt, and snow reflectivity (albedo) across the Greenland Ice Sheet, to better understand how modern climate change is affecting Greenland mass balance (how fast is it melting?) and global sea-level rise. These projects provide valuable field data needed to validate climate models used to predict future melting of the ice sheet with continued warming. Our latest project is called “GreenTrACS” (Greenland Traverse for Accumulation and Climate Studies), and includes 1000+ km snowmobile traverses across western Greenland in 2016 and 2017 (see figure). Along the traverses we are collecting snow/ice radar data showing annual snowfall layers, high-precision surface elevation data to track the lowering of the ice sheet, snow reflectivity data to see how pollution and warming are darkening the ice sheet surface, and a series of 16 ice cores to track snowfall and snow melting over the past 40-50 years. Check out our blog, and this YouTube video about the traverse.

Publications: Lewis et al., 2021Meehan et al., 2020; Lewis et al., 2019Lewis et al., 2017; Osterberg et al., 2015; Hawley et al., 2014; Wong et al., 2013

Response of the NW Greenland Ice Sheet to Holocene Climate Change

The aim of this collaborative project between researchers at Dartmouth, Northwestern and UMaine is to develop records of past climate in northwest (NW) Greenland and synthesize them with records of the ice margin position to evaluate the response of the Greenland Ice Sheet to past warm periods, such as the Holocene Climatic Optimum (approximately 5 to 9 thousand years ago). The research integrates multiple climate proxies collected from the Thule region with glaciological modeling experiments to address the following research objectives: (1) reconstruct Holocene climate in NW Greenland via inferences from reconstructed local ice cap extents (North Ice Cap, Tuto Ice Cap), ice core stable isotope and precipitation records, and data from nearby lake sediments; (2) Examine the sensitivity of the NW Greenland Ice Sheet (GIS) to Holocene climate changes by developing the history of the areal extent of the GIS and synthesizing proxy data with glaciological modeling experiments to examine past GIS changes and predict future GIS retreat. Results from this project will enable a more accurate prediction of the NW Greenland cryospheric response to a future warmer world and provide information directly relevant to predictions of future sea-­level rise.

Publications: Axford et al., 2019; McFarlin et al., 2018Lasher et al., 2017; Osterberg et al., 2015; Wong et al., 2015

The Decline of Alpine Glaciers

With rare exceptions, mountain glaciers worldwide have been melting and receding in recent decades, contributing to sea-level rise and reducing freshwater availability in glacier-fed river basins that rely on consistent summer melt. These losses can have harmful effects on hydropower generation, agriculture, and the health of aquatic ecosystems, and can even lead to downstream flash flooding. We aim to better understand the rates of ice loss and, collaborating with Professor Bob Hawley, we have done field work to estimate volume loss on the Athabasca and Peyto Glaciers in the Canadian Rocky Mountains. Yearly flows from these glaciers are essential in providing water to the agricultural lands of the Canadian prairie provinces, but our research has shown that mountain glaciers in the Canadian Rockies will lose 80-90% of their present-day volume by 2100.

Publications: Raphael et al., In Prep; Kerhl et al., 2014