The "market" that economists say about is their model of what they believe a market is, it's a mathematical model with a good amount of gaps, this is why you will always find economists disagreeing among them, it's not like physics because they have to decide to rely on more assumptions and less experimentation.

I used to work in earth sciences although not in glaciology, and their models are very sound to say about the now, not so much about the future, that glaciers retreats and expands is common knowledge (the Missoula flooding event is a good example), but I am sure with a warming planet, if that's the case, more glaciers would be retreating than expanding, this is easier to search for, but I know the World Glacier Monitoring Service have good data about that.