Documenting and Predicting Glacier Loss and Resulting Impacts

Left image

Kennicott Glacier, 1938

Right image

Kennicott Glacier, 2022

Kennicott Glacier and tributaries as seen obliquely from the south in 1938 (left) and 2022 (right). Note the extensive development of proglacial lakes downstream of the debris-covered lower glacier in the modern image, reflecting significant thinning and terminus retreat since the end of the mining era.

Two new papers document past and future glacier change in Wrangell-St. Elias National Park and Preserve. Kennicott Glacier and its tributary Root Glacier, both easily accessed from Kennecott Mines National Historic Landmark, were the subjects of both studies. The two papers use historic and recently acquired data to track changes over the past 85 years. They show that before 1957, the glaciers were mostly stable but have since then been shrinking faster and faster. Weather data, lake bathymetry measurements, and melt records help to explain the causes and consequences of these changes.

In one paper, the researchers used these observations to constrain glacier models that, depending on how much greenhouse gas is released into the atmosphere, project

Kennicott Glacier could lose between 38% and 63% of its ice by the year 2100.

Root Glacier could lose between 38% and 58% of its ice by 2100.

What’s important is that these new predictions are more accurate than older ones because they use a much longer history of glacier changes—not just the last 20 years. This helps scientists better understand how glaciers respond to climate change and how that affects things like sea level rise, water supplies, and natural hazards. Park management and local residents can use these findings to guide decisions about development and infrastructure in the Kennicott Valley and at the Historic Landmark.

This work was supported by the Central Alaska Inventory & Monitoring Network and conducted by National Park Service geologists Michael Loso and Chad Hults, along with lead authors Albin Wells from Carnegie Mellon University and Eric Petersen from the University of Alaska Fairbanks, and with additional collaborators from Pennsylvania, Alaska, Colorado, Arizona, Utah, Norway, and China.

An 85-year record of glacier change and refined projections for Kennicott and Root Glaciers, Alaska

Abstract

Long-term historical records of glacier mass change are key to advancing understanding of glaciers’ response to climate change and improving predictions of their future. Here, we use historical aerial photographs and new bed topography measurements to provide an 85-year record of glacier change on Kennicott and Root Glaciers in Alaska. At the glacier terminus, little change is observed in the two decades prior to 1957, followed by ongoing and accelerating mass loss with dynamically driven spatial variability. Glacier projections, constrained by these mass loss estimates, predict that Kennicott Glacier will lose 38 ± 14% to 63 ± 18% of its mass by 2100, relative to 2000, and Root Glacier will lose 38 ± 11% to 58 ± 12%, depending on the emissions scenario. These results differ by up to 22% from similar predictions made by projections calibrated from the past two decades of glacier change only. This highlights the importance of long-term glacier mass-loss records that help us better project far-reaching consequences of climate change related to sea level rise, water resources, natural hazards, climate, and culture.

Wells, A., B. S. Tober, S. F. Child, D. R. Rounce, M. G. Loso, C. P. Hults, M. Truffer, J. W. Holt, and M. S. Christoffersen. 2025. An 85-year record of glacier change and refined projections for Kennicott and Root glaciers, Alaska. Nature Communications 16: 7835.

Multi-Year Glaciological and Meteorological Observations on Debris-Covered Kennicott Glacier, Alaska, 2016–2023

Abstract

Despite increasing availability of satellite-derived products, in situ glacier observations are pivotal to accurately monitor glacier change and to calibrate and validate glacier models. However, comprehensive multi-variable field observations are especially rare on large glaciers and on debris-covered glaciers. Here we present extensive field observations from Kennicott Glacier, a heavily debris-covered glacier in central Alaska covering more than 400 km2. The multi-year data set includes point glacier mass balances, meteorological data from several weather stations on and off the glacier, debris thickness and temperature, ice cliff back wasting derived from time-lapse photography of horizontal stakes drilled into several cliffs, and bathymetry, water temperature, and water level of proglacial and supraglacial lakes. Cumulated summer melt of more than 8 m was observed at the lowest clean-ice sites. Melt rates over clean ice correlate well with elevation, while the rates over debris-covered ice lack any strong elevation dependence. Melt rates drop exponentially with increasing debris thickness and tend to be much lower than for clean ice at similar elevations. Melt rates determined for ice cliffs in areas of otherwise continuous debris cover were up to 10× those for debris-covered ice, and even exceeded standard clean ice melt rates. Debris-cover thickness measurements at 150 sites vary from < 1 to 69 cm with an average of 17 ± 11 cm (±standard deviation). Debris thickens down-glacier, but with high spatial variability–thickness was observed to vary by tens of cm within a ~15 m radius. Depth-averaged thermal heat conductivity derived from supraglacial debris temperature profiles at 12 sites ranges from 0.53 to 1.86 W m−1 K−1. Interconnected proglacial lakes covered 1.61 km2 in 2018 with observed water depths of more than 60 m in the two largest lakes.

Petersen, E. I., R. Hock, M. G. Loso, W. Guo, C. Markovsky, R. Yang, H. Han, D. Shangguan, and S. Kang. 2025. Multi-year glaciological and meteorological observations on debris-covered Kennicott Glacier, Alaska, 2016-2023. Geoscience Data Journal 12(4): e70032.

Download the dataset

Petersen, E., R. Hock, M. Loso, W. Guo, C. Markovsky, R. Yang, H. Han, S. Donghui, and K. Shichang. 2025. Data products associated with "Multi-year glaciological and meteorological observations on debris-covered Kennicott Glacier, Alaska, 2016-2023."

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