“Scientists discovered that the glacier’s underwater base has been eroding due to the increase in the Earth’s temperature...”
The glacier is about the size of Florida, so, first of all, the scientists need to make plain just how they managed to scan the entire land base of the glacier, then map out just how global warming can penetrate miles of a thick sheets of ice and thaw it all out from the bottom. The warming would have to come from below, out of contact with carbon dioxide in the atmosphere.
Aha, so the glacier has an “underwater base” meaning it actually is situated in water and not on land.
Please see basic physics 101:
https://www.miniphysics.com/does-water-level-rises-when-ice-cube-is.html