Case Study 04 – Mountain glaciers: Áakʼw Tʼáak Sítʼ (Mendenhall Glacier) in Global Tipping Points Report 2025

• Mountain glacier tipping behaviour depends on a complex interplay between topography and climate, with mountain glaciers that experience similar external forcing having the potential to respond differently depending on local conditions.
• Áakʼw Tʼáak Sítʼ as well as the broader Juneau Icefield and its outlet glaciers have been suggested as a potential mountain glacier tipping system, with the segmentation of the glacier into multiple components (“glacier disconnection”) and the bedrock hypsometry leading to nonlinear mass loss and glacial retreat.
• Rapid deglaciation of Áakʼw Tʼáak Sít’ and other glaciers disrupts the relationship between Indigenous communities, glaciers, and glacial landscapes, depriving future generations of this component of their identity and history, which are inseparable from the land.
• The retreat of Áakʼw Tʼáak Sítʼ’s tributary glaciers has led to annual outburst floods in Juneau; future occurrence of these floods will depend on the rates and pattern of ice retreat.
• Rapid mass loss of Áakʼw Tʼáak Sítʼ could negatively impact tourism in Juneau as the glacier retreats from the Mendenhall Glacier Visitor Center viewshed, which is visited, on average, by every third visitor to the state of Alaska.
• The economic consequences of crossing a glaciological tipping point on fishing and salmon stocks are less clear, given the complex interplay of water temperature, air temperature, nutrient availability, and riverbed scouring in glacially influenced aquatic ecosystems.

Citation

Dennis D. P, Davies B. J., Ehrenfeucht S., Ely J. C., Nicholson L., Ord A., Ramos J. D., Winkelmann R.. 2025. Case Study 04 – Mountain glaciers: Áakʼw Tʼáak Sítʼ (Mendenhall Glacier) in Global Tipping Points Report 2025. Global Tipping Points Report 2025. 267-280. https://global-tipping-points.org/download/1418/.