Venus is a perfect example of the greenhouse effect. Sunlight passes through the clouds in the form of radiation. The sunlight is absorbed by the surface causing it to heat. The cloud layer, which is opaque, traps the heat causing the greenhouse effect. Because of the heavy cloud layer, only about 2% of the sunlight reaches the surface of Venus. Imagine what it would be like if 100% of the light reached the surface.
A place which receives almost no light and is very hot, is obviously not being heated by the greenhouse effect. Venusian nights last for months, there is no incoming SW radiation, yet the temperature never cools down at all. Only a complete moron would blame the heat on Venus on “the greenhouse effect.”
Enter Sagan and Hansen.