[Illustrations, footnotes and references available in PDF version]
The Earth’s atmosphere differs in essence from that of Venus and Mars. Our atmosphere is not totally cloud-covered, as is Venus: globally, about 40% of the sky is always clear. Also we have huge ocean surfaces that serve as a practically unlimited reservoir of water vapor for the air.
With the help of these two conditions, the Earth’s atmosphere attains what the other two planets cannot: a constant, maximized, saturated greenhouse effect, so that adding more greenhouse gases to the mix will not increase the magnitude of the greenhouse effect and, therefore, will not cause any further “global warming”.