And who exactly created them to invalidate Velikovsky?
please see this post
The Discovery of Global Warming June 2011
Venus & Mars
In the 1960s and 1970s, observations of Mars and Venus showed that planets that seemed much like the Earth could have frightfully different atmospheres. The greenhouse effect had made Venus a furnace, while lack of atmosphere had locked Mars in a deep freeze. This was visible evidence that climate can be delicately balanced, so that a planet's atmosphere could flip from a livable state to a deadly one.
Already back in 1940, Rupert Wildt had made a rough calculation of the greenhouse effect from the large amount of CO2 that others had found in telescope studies of Venus; he predicted the effect could raise the surface temperature above the boiling point of water. But raising it as high as 600°K seemed impossible.(4*) Nobody mounted a serious attack on the problem (after all, very few people were doing any kind of planetary astronomy in those decades). Finally in 1960 a young doctoral student, Carl Sagan, took up the problem and got a solution that made his name known among astronomers. Using what he later recalled as "embarrassingly crude" methods, taking data from tables designed for steam boiler engineering, he confirmed that Venus could indeed be a greenhouse effect furnace.(5) The atmosphere would have to be almost totally opaque, and this "very efficient greenhouse effect" couldn't all be due to CO2. He pointed to absorption of radiation by water vapor as the likely culprit
So Carl Sagan was wrong about "Venusian warming"
His starting assumption was that Venus was always where it is
The discovery that Venus's atmosphere had a composition, and probably a history, very different from Earth's prompted scientists to abandon their old assumption that planetary atmospheres were fixed forever by simple chemistry[/b
What?????? a different history!!
what on Venus could that possibly mean?
The atmosphere of Venus was filled not only with CO2 but also with an opaque haze. Its nature was unknown, and in the 1960s scientists could only say that the haze was probably caused by some kind of tiny particles.(10) "The clouds on Venus had long been a mystery," as one expert recalled, "in which stratospheric aerosols now appeared to play a key role. The unraveling of the precise role of aerosols in the Venus atmosphere would certainly benefit studies of chemical contamination of Earth's atmosphere." (11*) In the early 1970s, ground-based telescope observations produced extraordinarily precise data on the optical properties of these aerosols, and at last they were identified. The haze was from sulfur compounds.(12*)
The greenhouse effect of the sulfates could be calculated, and by the late 1970s, NASA climate modeler James Hansen stated confidently that the sulfates together with CO2 "are responsible for the basic climatic state on Venus." Hansen had originally become interested in the greenhouse effect when, in response to Sagan's primitive calculations, he tried to derive a better explanation of why the planet's atmosphere was so hot. Now Hansen's findings about sulfate aerosols strengthened his belief that these particles could make a serious difference for the Earth's climate as well. Sulfates were emitted by volcanoes and, increasingly, by human industry, so Venus had things to tell us about climate change at home.(13*) (CO2 was by far the largest factor in warming Venus, and the effect of sulfates would be debated for decades. It turned out that the greenhouse effect of sulfate clouds reflecting heat back to the surface of Venus was outweighed by cooling due to their reflection of incoming sunlight.)
So Hansen was wound up about sulfate aerosols........
Sagan was encouraged by those wanting a different reason for Venus being warm
his explanation was readily accepted, even though it was simplistic and wrong
He became famous for having the wrong but politically correct answer (something to refute Velikovsky)
the how and whys of "global warming" change over time
but the belief in it exists soesn't