3 Retreat, Stabilization, and Regrowth of Crane Glacier
Remote sensing observations collected around the collapse event have
been thoroughly discussed in the literature. Ice shelf terminus retreat
and thinning preceded the rapid collapse of the LBIS in February to
March of 2002 (Glasser & Scambos, 2008). We refine the following record
found in the literature, which showed little change at Crane immediately
post-collapse in 2002 (Scambos et al., 2004), followed by accelerated
mass loss from 2003-2007 (Scambos et al., 2011), and a slow deceleration
of ice loss from 2008-2013 (Wuite et al., 2015).
The MICI hypothesis, invoked for Crane, is predicated on the idea that
calving by cliff failure (and terminus retreat into thicker ice with
taller cliffs) causes an acceleration of the calving rate that outpaces
the ability of Crane to viscously thin and inhibit calving. Below, we
reframe and extend the observational record of Crane Glacier from
2002-2021 to highlight three distinct periods with the MICI hypothesis
in mind: the initiation of fracture processes and accelerating terminus
retreat, the stabilization of the glacier terminus, and the regrowth and
return to glacier equilibrium with the modern climate. We argue these
data show the disequilibrium behavior of Crane Glacier during retreat,
including a positive geometric feedback as retreat accelerates, and
hysteresis in its response as it returns to an advanced but thin
configuration within the modern climate.