Question

On molecular level what I causing the glaciers to melt

Answer 1

Glaciers capture large amount of carbon dioxide from atmosphere. When concentration of carbon dioxide molecules in glaciers increase, then strength and fracture toughness of ice are decreased and that make glaciers vulnerable to cracking and splitting into fragments.
That is because hydrogen bonds between water molecules in glaciers is decreased under increasing concentrations of carbon dioxide who competes with the water molecules connected in the ice crystal.