Earth is about the same size as Venus, but temperatures are much cooler here. The primary difference between Earth and Venus is that we have oceans which absorb CO2 and form limestone – CACO3. Without the massive limestone deposits we have on Earth, the atmosphere would be much denser and temperatures would be much higher.
Venus is too close to the Sun to have liquid water. The water evaporated away, so volcanic CO2 kept accumulating, and their atmosphere became 100X more dense that of Earth.
The world’s leading climatologist – James Hansen – based his PhD dissertation on the idea that Venus was hot because of aerosols. Carl “Reefer Madness” Sagan later convinced him that Venus was hot because of a “runaway greenhouse effect” and now Hansen says the exact opposite – that Chinese aerosols make earth cool.
In order to become the world’s leading climatologist, you have to demonstrate that you have no clue about atmospheric physics.