Most of the “greenhouse effect” is provided by water vapor, CO2 is indeed a small component of the effect by itself. CO2 is the point of concern because the ca

Most of the “greenhouse effect” is provided by water vapor, CO2 is indeed a small component of the effect by itself. CO2 is the point of concern because the carbon cycle is slow. Any CO2 we add will be there for many decades. So it’s like compound interest: a small change over time adds up to a noticeable effect. The water cycle is very short, extra water vapor rains out quickly. This explains the physics: https://en.m.wikipedia.org/wiki/Greenhouse_effect https://en.m.wikipedia.org/wiki/Greenhouse_effect