On Jan. 24, 1984, the CBC television program The Journal broadcast a full edition documentary called "The Greenhouse Effect and Planet Earth." It was hosted, narrated and written by Peter Kent, who is now Canada's environment minister.
You can find the program here.
And you may want to hurry. Evidence of this sort has a tendency to mysteriously disappear from the web.
In his introduction to the documentary, Kent says that it may seem like science fiction but "the scientific community is virtually unanimous": the planet is getting warmer.