Does "globalism" really play a role here? There are self-proclaimed nationalist parties today and in history that also caused great environmental destruction. And to a certain extent, shipping freight from say China to west-coast USA is equally as polluting as shipping from west-coast USA to east-coast USA.

Consumption causes externalities, yes, but I believe a global trade economy is overall more efficient than nationalist segmented economies, thus the overall pollution load should theoretically be lower with globalism.