What makes you think that all pollutants are attracted to Canada like a Duck to Water? Does Canada have a Huge heat and pollution magnet somewhere?
i don't think such silliness.
the fact that the u.s. appears to be immune from the higher temps in 1998 and 2010 is likely explained by el nino. because temps tend to be cooler in the u.s. during el nino, whereas they tend to be higher during la nina years, like 2005. they provide an el nino vs. la nina chart, take a look and tell me if you agree.
as far as the heat near the poles, *yawn*. the poles have seasonal ozone. thus they get more and more hotter when they get hotter, and more and more cooler when they get cooler. just like how your soil has a hotter internal temperature at the last 100 degree day of a heat wave than it does at the first 100 degree day of the heat wave. the lows in the winter are marginally warmer, and the highs in the summer are marginally hotter. thus, the overall average, which is what you see represented in the pretty pictures, is overall hotter.
but it goes beyond that....the hots are hotter AND the cools are cooler. climate change is always happening, but not this rapidly. the line on the graph is getting steeper IN BOTH DIRECTIONS. it is not really human caused climate change, which is a stupid term because the climate ALWAYS chnages....it is more like human caused climate instability.