In my opinion, there has not yet been enough increase in temperature in the northern hemisphere to account for all the documented melting here and there.
The worst- known/suspected melting agent at this point seems to be the large increase in sunray- absorbing black soot emitted by coal- fired generation in emerging nations. Western nations do a fair job of removing soot particulates, while those coming late to the party haven’t made any efforts to control black soot and other particulates, not yet, at least. They do promise to do something about it after their economies catch up to ours.