Abstract
Abstract. Evolution of glaciers in response to climate change has mostly been simulated using simplified dynamical models. Because these models do not account for the influence of high-order physics, corresponding results may exhibit some biases. For Haig Glacier in the Canadian Rocky Mountains, we test this hypothesis by comparing simulation results obtained from 3-D numerical models that deal with different assumptions concerning physics, ranging from simple shear deformation to comprehensive Stokes flow. In glacier retreat scenarios, we find a minimal role of high-order mechanics in glacier evolution, as geometric effects at our site (the presence of an overdeepened bed) result in limited horizontal movement of ice (flow speed on the order of a few meters per year). Consequently, high-order and reduced models all predict that Haig Glacier ceases to exist by ca. 2080 under ongoing climate warming. The influence of high-order mechanics is evident, however, in glacier advance scenarios, where ice speeds are greater and ice dynamical effects become more important. Although similar studies on other glaciers are essential to generalize such findings, we advise that high-order mechanics are important and therefore should be considered while modeling the evolution of active glaciers. Reduced model predictions may be adequate for other glaciologic and topographic settings, particularly where flow speeds are low and where mass balance changes dominate over ice dynamics in determining glacier geometry.
Highlights
Over the past several decades, glaciers and ice caps have been shrinking in most regions of the world (e.g., Paul et al, 2004; Lemke et al, 2007; Scherler et al, 2011) as they try to equilibrate with ongoing climate warming (e.g., Hansen et al, 2006)
It appears that glaciers retreat in response to warming climate, glacier–climate interactions involve the complex nature of mass balance (e.g., Zemp et al, 2011), ice dynamical adjustments (e.g., Schneeberger et al, 2001), and associated time lags (Jóhannesson et al, 1989)
We examine the transient response of Haig Glacier for both (i) specified changes in climate and (ii) climate forcing under Representative Concentration Pathway (RCP) future emission scenarios 4.5 and 8.5 for the 21st century
Summary
Over the past several decades, glaciers and ice caps have been shrinking in most regions of the world (e.g., Paul et al, 2004; Lemke et al, 2007; Scherler et al, 2011) as they try to equilibrate with ongoing climate warming (e.g., Hansen et al, 2006). Changes in glacial systems will have a large impact on global sea level (e.g., Raper and Braithwaite, 2006; Meier et al, 2007; Radicand Hock, 2011; Jacob et al, 2012) and regional water resources (e.g., Huss, 2011; Marshall et al, 2011; Bolch et al, 2012) It appears that glaciers retreat in response to warming climate, glacier–climate interactions involve the complex nature of mass balance (e.g., Zemp et al, 2011), ice dynamical adjustments (e.g., Schneeberger et al, 2001), and associated time lags (Jóhannesson et al, 1989).
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