This whole global warming thing
...is totally NOT and open and shut case. And even if it happens, Canada will be a winner so SWEET!...
I certainly wouldn't let facts confuse the issue, but global warming is a measurable fact. As is the fact that the magnetic pole is shifting southward (as it once was) and that earthquakes, volcanoes, tsunamis, hurricanes, etc will continue.
Another fact is that the exponential increase of greenhouse gas is well correlated with the onset and evolution of the industrial revolution.
The only thing we can do anything about all of the above is the greenhouse gas issue.
As for Canada being a winner, it depends on exactly which part of Canada you are talking about and at what point in the future.