The reason the SSD was destroyed was the auxialiary command crew couldn't get to the reserve bridge in time to stop the garavitic pull of the DSII to stop it 'falling' into the station. The same would happen with an ESSD, and i suspect the Imperials learnt a valuable lesson about crewing reserve bridges.
It's very unlikely that it would happen over the period of a few days. Whilst a catastrophic event could in theory cause an ice age in a matter of weeks, it's much more likely to be a long term degredation into one.
I remember listening to an article on Radio 4 (yes Jahled i'm that sad) about it where they were saying that they were quite aware it wasn't realistic, much like pretty much every other film. Ever.