[Retra]

Because the crack isn't the fundamental problem. The problem is that the ice sheet is too small to resist temperature changes. Purposefully making the ice sheet smaller yet only exacerbates the problem.

The only reason anyone cares that there is a crack is because it implies that the ice is shrinking.

[euyyn]

Why does a bigger span of ice make it more resistant to temperature changes?

[Retra]

Lower surface area and higher albedo.

[euyyn]

Why does albedo increase the larger the shell is? I would have thought it'd only depend on whether the surface was in the form of snow or ice.

And wouldn't a larger shell expose a bigger surface area?