Alternative theory for globalization.

I am watching 'The day after tomorrow' and I am at the part where the Americans are trying to cross the Mexican border to escape the storms when something came to my mind. Could globalization be for more than just corporations? The Mexican government closed their border because of too many Americans which made me think; Could the Unions such as European Union, African Union, etc... Are the being established for more than free internal trade but also for stopping borders in case of an impending or potential disaster that could force the evacuation of millions maybe billions of people? Instead of keeping borders closed they have a reason to force other nations to keep their borders open.

This is just a theory and I would like feedback.

I would really like some input on this theory.