How does the proportion of carbon dioxide in the atmosphere differ between Earth and Venus?
The proportion of carbon dioxide (CO2) in the atmosphere differs significantly between Earth and Venus.
On Earth, the current average concentration of carbon dioxide is about 410 parts per million (ppm), which means that for every million air molecules, approximately 410 molecules are carbon dioxide. This accounts for about 0.041% of the Earth's atmosphere.
In contrast, Venus has an extremely high concentration of carbon dioxide, making it the planet with the highest CO2 content in its atmosphere. Venus' atmosphere is composed of around 96.5% carbon dioxide, which is equivalent to more than 965,000 ppm. This means that for every million air molecules, over 965,000 molecules are carbon dioxide.
Therefore, the proportion of carbon dioxide in Venus' atmosphere is almost 2500 times higher than that of Earth. This extreme level of CO2 is responsible for Venus' intense greenhouse effect, leading to extreme temperatures and a runaway greenhouse effect on the planet.