I think you need remember that the first ice lost is cork in a very large bottle of bubbly?
It may need the blunt tool of 'temperature' alone to melt it/remove it but once it's gone?
But the vast majority of the next phase of losses will be gravity driven and not need temp's help at all?
Though 'small', as a percentage of the total mass of contents , that there cork needs be removed before the real action can begin?
As we advance in our understanding of 'glaciation/de-glaciation' I've met with some head slapping realisations about just how rapidly an ice sheet can destabilize/disappear?
Just remove those corks eh?