Yes, the greenhouse effect exists on both Earth and Venus. The greenhouse effect is a natural process by which certain gases in a planet's atmosphere, known as greenhouse gases, trap and re-radiate heat, leading to an increase in surface temperature. The primary greenhouse gases on Earth are carbon dioxide (CO2), methane (CH4), and water vapor (H2O), among others. On Venus, the main greenhouse gas is carbon dioxide, with an atmosphere composed mostly of it.
In terms of which planet experiences a stronger greenhouse effect, Venus has a much more pronounced greenhouse effect compared to Earth. Venus has an extremely dense atmosphere predominantly composed of carbon dioxide, which creates a very strong greenhouse effect. The thick atmosphere traps a significant amount of heat, causing Venus to have a surface temperature of around 462 degrees Celsius (864 degrees Fahrenheit), making it the hottest planet in our solar system.
On Earth, while the greenhouse effect is essential for maintaining habitable temperatures, human activities have significantly increased the concentration of greenhouse gases, particularly carbon dioxide, leading to enhanced warming. This anthropogenic influence has contributed to global climate change. However, the intensity of the greenhouse effect on Earth is not as extreme as on Venus, and the surface temperatures are within a range suitable for life as we know it.