I saw this link mentioned by a prominent left-wing columnist at Facebook, and was very interested in it.

This is a picture of a proposed ad Avaaz.org wishes to run in the Wednesday version of the Washington Post a day before Obama is scheduled to visit Canada (to prevent eye injury from squinting, click on ad to enlarge and read in full):

Their mission statement on this ad reads as follows:

When Barack Obama visits Canada on Thursday, Harper will desperately try to push him to agree to exempt dirty tar sands oil from global regulation – effectively undermining the global deal we need to stop catastrophic climate [...]