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Termini of calving glaciers as self-organized critical systems

November 10, 2014

Over the next century, one of the largest contributions to sea level rise will come from ice sheets and glaciers calving ice into the ocean1. Factors controlling the rapid and nonlinear variations in calving fluxes are poorly understood, and therefore difficult to include in prognostic climate-forced land-ice models. Here we analyse globally distributed calving data sets from Svalbard, Alaska (USA), Greenland and Antarctica in combination with simulations from a first-principles, particle-based numerical calving model to investigate the size and inter-event time of calving events. We find that calving events triggered by the brittle fracture of glacier ice are governed by the same power-law distributions as avalanches in the canonical Abelian sandpile model2. This similarity suggests that calving termini behave as self-organized critical systems that readily flip between states of sub-critical advance and super-critical retreat in response to changes in climate and geometric conditions. Observations of sudden ice-shelf collapse and tidewater glacier retreat in response to gradual warming of their environment3 are consistent with a system fluctuating around its critical point in response to changing external forcing. We propose that self-organized criticality provides a yet unexplored framework for investigations into calving and projections of sea level rise.

Publication Year 2014
Title Termini of calving glaciers as self-organized critical systems
DOI 10.1038/ngeo2290
Authors J. Astrom, D. Vallot, M. Schafer, E. Welty, Shad O'Neel, T.C. Bartholomaus, Y. Liu, T. Riikila, T. Zwinger, J. Timonen, Johnnie N. Moore
Publication Type Article
Publication Subtype Journal Article
Series Title Nature Geoscience
Index ID 70133363
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center