Fig. 3: Grounding line retreat and irreversibility.
From: Ocean warming as a trigger for irreversible retreat of the Antarctic ice sheet
a, Grounding line positions through time at ten-year intervals during the 100-year NEMO4 perturbed simulation using the Mmat parameterization (Methods). The background is bed topography from BedMachine v229 in meters above sea level (m a.s.l.) shown on x and y coordinates in polar stereographic (ps) projection. White lines show profiles along key ice streams, and white dots are at 20-km intervals inland of the initial grounding lines. Coloured circles show the location of reversibility experiments, which correspond to the coloured circles shown in panels b–g. b–d, The grounding line positions extracted along these profiles during the forward-in-time experiments, for the Möller ice stream (b), Thwaites Glacier (c) and Bindschadler ice stream (d) profiles. Coloured lines represent the different forward perturbation experiments (legend in c). Grey shading shows phases of accelerated retreat. e–g, The grounding line positions during the reversibility experiments (the timing of which is denoted by the coloured circles), where purple and orange lines are when the melt rates were reverted to control conditions for the NEMO4 and \({{\rm{FESOM}}}_{\sigma }^{{\rm{high}}}\) experiments, respectively. Red lines are where the control melt rates were reduced by 50%. The line style in b–g denotes the choice of melt rate parameterization (legend in e). The shaded orange shows periods of continued retreat during the reversibility experiments. In g, the grey shaded region is a period of re-advance. Note the difference in y-axis scales for Thwaites Glacier (c,f).
