Recent and ongoing research themes

Holocene climate and glacier reconstruction.

My recent work has largely focused on analysis of physical and geochemical properties of proglacial lake sediment to infer changes in glacier size over the Holocene. I use these sedimentary indicators alongside geomorphic evidence of past glacier extent (e.g., the positions of moraines and trimlines) to model past glacier surfaces and their associated equilibrium–line altitudes (ELAs; a mass–balance modulated parameter) to develop quantitative reconstructions of past climate conditions. 

Historical climate and glacier change.

Owing to their remote and logistically challenging setting, direct field measurements on Arctic glaciers are very rare. Rather, most studies have relied on satellite imagery and other space–based observations to estimate glacier area, volume, or length change, but are inherently restricted to the satellite era, which began in the late 1970s. I combine geomorphic evidence (e.g., moraines and trimlines) and historical observations (e.g., air photos) with modern satellite imagery to extend the limited time frame of observational records of glacier change.

Contemporary glacier status and future change.

The nearly worldwide contraction of glaciers is considered one of the most visible signs of ongoing anthropogenic warming. In recent decades, glaciers and ice caps distinct from Earth's ice sheets have been responsible for roughly one-third of the observed rise in eustatic sea-level. My postdoctoral research is focused on better understanding the Arctic's glaciers contemporary and future status.  Ultimately, this work aims to identify which of the Arctic’s 50,000+ land–based glaciers are most at risk of melting away first under different future warming scenarios. Along with raising global sea level, glacier loss is expected to have a myriad of sociocultural and economic ramifications for Arctic communities, and to negatively alter hydrological systems at a local scale (affecting water availability and quality, as well as downstream aquatic ecosystems). 

Data syntheses. 

To date, there are relatively few continuous records of glacier variations inferred from lake sediments over the Holocene across the Arctic—a vast area, which hosts a wide range of modern climates. I recently compiled all available lake-based glacier records (n = 66) from seven Arctic regions. The work summarizes evidence for when glaciers were smaller than today or absent altogether, and evidence for when glaciers regrew in lake catchments. Most importantly, the synthesis strongly reinforces that relatively modest summer warming (compared with projections of larger future climate change) drove major environmental changes across the Arctic including the widespread loss of smalll mountain glaciers.