All of this nonsense was started "Billions and Billions" of years ago by Carl Sagan. (Well, OK, 35 years ago in his
Cosmos TV program.) Or, at least, that's when he began popularizing it. As far back as the '60s, he speculated that the temperatures on Venus were much higher than thought at the time. This was confirmed by the Mariner probes. He eventually blamed "Greenhouse Gasses" for the runaway overheating of Venus. The "Global Cooling" and "Nuclear Winter" crowd switched to warming after Sagan's TV show became so popular.
Here's a good essay on Sagan's contribution to what became a fraud:
The Original Sin of Global Warming
Pat