The two biggest melts for Greenland were in 1889 and 2012. We didn't know why the entire surface of Greenland turned to slush in a 96 hour period back when it happened, but now we know it was warm, ash laden air and that a similar event happened in 1889. This is double the normal maximum summer melt area.
Greenland melting is an issue on a scale of centuries to maybe a whole millennium, but there are other icy places that are much closer to fires. The Himalayas, which translates into The Abode of Snow, are commonly called Asia’s water tower. I have already mentioned the Kashmir Conflict, which affects the headwater’s of the Indus river valley at the far western end of the range. The Ganges and the Brahmaputra also originate in the Himalayas and well over a billion people depend on the mountain glaciers as a buffer for precipitation.