Understanding drivers of glacier-length variability over the last millennium

Alan Huston, Nicholas Siler*, Gerard H. Roe, Erin Pettit, Nathan J. Steiger

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Changes in glacier length reflect the integrated response to local fluctuations in temperature and precipitation resulting from both external forcing (e.g., volcanic eruptions or anthropogenic CO2) and internal climate variability. In order to interpret the climate history reflected in the glacier moraine record, the influence of both sources of climate variability must therefore be considered. Here we study the last millennium of glacier-length variability across the globe using a simple dynamic glacier model, which we force with temperature and precipitation time series from a 13-member ensemble of simulations from a global climate model. The ensemble allows us to quantify the contributions to glacier-length variability from external forcing (given by the ensemble mean) and internal variability (given by the ensemble spread). Within this framework, we find that internal variability is the predominant source of length fluctuations for glaciers with a shorter response time (less than a few decades). However, for glaciers with longer response timescales (more than a few decades) external forcing has a greater influence than internal variability. We further find that external forcing also dominates when the response of glaciers from widely separated regions is averaged. Singleforcing simulations indicate that, for this climate model, most of the forced response over the last millennium, preanthropogenic warming, has been driven by global-scale temperature change associated with volcanic aerosols.

Original languageAmerican English
Pages (from-to)1645-1662
Number of pages18
Issue number3
StatePublished - 1 Apr 2021

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