
I hadn’t seen this before – this is classic.
Apparently Hansen claimed in 1983 that the opacity of Venus atmosphere to IR is 100 times greater than Earth.
What utter tripe. In the year 1900, Angstrom demonstrated that IR absorption in a tube of CO2 became saturated at one atmosphere, and that adding more CO2 had very little effect on opacity. Not to mention the fact that CO2 absorption bands almost completely overlap with much broader (and much more abundant) H2O absorption bands.
The atmosphere is 70-85% opaque to IR radiation. The largest possible increase is less than 50%, not 10,000% as Hansen claims.

File:Atmospheric Transmission.png – Global Warming Art
Perhaps he was confusing opacity with transparency? If Earth’s atmosphere was 0.01% transparent, and Venus atmosphere was 0.0001% transparent – then he could say that Venus atmosphere is 100X less transparent. But that difference would have almost no effect on the temperature.


Projecting future sea level rise: methodology, estimates to the year 2100
No Homer, the lapse rate on Venus is nearly identical to Earth. If opacity was the problem, the lapse rate would have to be much higher on Venus.
The reason that Venus is hot is because it has a very thick atmosphere. If the composition of Venus atmosphere was identical to Earth’s atmosphere, temperatures would still be extremely hot on Venus.
This wasn’t Hansen’s first trip into Venusian stupid space. His doctoral dissertation claimed that Venus was very hot due to aerosols – the same aerosols which he now says cool Earth and hide the missing heat.
Sometimes I wonder how this guy made it past high school.