Citation
Columbia Glacier Photographic Collection
TL;DR
Columbia Glacier terminus stable for 200+ years at 67km from source
Documents the 20km retreat of Columbia Glacier from 1980-2020, providing the empirical foundation for the chapter's central biological metaphor. The photographic record spanning nearly two centuries demonstrates how a system can remain stable for extended periods before entering catastrophic positive feedback.
Post's work shows that the trigger for Columbia Glacier's retreat was geometric (retreating off a shallow underwater ridge into deep water), not climatic - a crucial insight for understanding that organizational calving triggers are often structural rather than external.
Key Findings from Post & al. (2011)
- Columbia Glacier terminus stable for 200+ years at 67km from source
- Retreat began 1982, accelerated through 2020
- 20km retreat in 40 years exceeded previous 10,000 years of change
- Geometric trigger: terminus retreated off shallow ridge into deep water