Actually, Epidemic, you are but partly correct
you little troublemaker as although Canada
does export a great deal of atmosphere, they are not alone in this normal trade operation.
Britain imports a great deal of THEIR atmosphere as well, although the pickens' in the far Atlantic are so slim, all they usually get is this dense 'London Fog'...at least that's what the label in my dad's long coat said.
And if I can't trust the label in dad's coat, what can I trust?
Furthermore, there are many other countries who import/export atmosphere. We export a great deal of acid rain to Canada. They hate it. Perhaps they had a reason, as you suggest, for this gratuitous export of surplus cold atmosphere?