Global warming results not from the emission of greenhouse gases into the atmosphere, but from an unusually high level of solar radiation and a lengthy - almost throughout the last century - growth in its intensity.

Mars has global warming, but without a greenhouse and without the participation of Martians. These parallel global warmings - observed simultaneously on Mars and on Earth - can only be a straightline consequence of the effect of the one same factor: a long-time change in solar irradiance.