Sack Lunch Seminar (SLS)

Abstract:
Glaciers are captivating and consequential elements of the climate system, and in many parts of the world their history forms the primary record of paleoclimate against which other proxy records are interpreted. However glaciers are not simply passive recorders of climate; they have a finite response time that is set by their dynamics and geometry. Like any such system, a glacier will integrate stochastic, year-to-year fluctuations in accumulation and melting, and produce more persistent fluctuations away from equilibrium. In other words, there will be natural glacier variability that occurs in a constant climate. The question then becomes how large or frequent are the natural fluctuations relative to those interpreted to have required a climate change? I'll present a newly developed, simple glacier model that effectively emulates the behavior of numerical models that lays bare how the natural variability depends on glacier geometry and climate variance; and apply the model to two well-documented glaciers: Franz Josef, New Zealand, and Nigardsbreen, Norway.