Home > Data, Omniclimate, Science, Skepticism > Venus Missing Greenhouse Warming

Venus Missing Greenhouse Warming

(third post in a series dedicated to the planet Venus as “example” of runaway greenhouse warming)
Venus post #1: Venus: Cool Greenhouse?
Venus post #2: Venus Warming Revisited
Venus post #3: Venus Missing Greenhouse Warming
Venus post #4: Venus and a Thicker-Atmosphere Earth

Let’s compute (in a simplified manner!) what would happen were Earth suddenly equipped with an atmosphere as massive as Venus’ (ie 90 times more than ours).

Given the similarities in mass and diameter of the two planets, we can assume this new atmosphere would behave similarly to Venus’, and in particular, purely adiabatically below 60km (instead of below 12km as at present).

For another simplification, let’s also imagine the new atmosphere to be just as our current one but without any water.

The lapse rate for dry Earth atmosphere is known and is 9.760 K/km.

How higher would the surface temperature be, with a dry atmosphere and a 60-km-thick troposphere?

9.760 * (60-12) = 468K higher than at present (288K)

The total for Earth is then 756K. Compare that to Venus’ surface temperature of 735K.

For an amazing coincidence, that’s 97% of the above, whilst the ratio of absorbed Solar radiation at Venus compared to Earth is… 96%.


Note how the increase in temperature doesn’t depend on any greenhouse gas.

And so do we really need to believe in greenhouse warming when mere mass can explain the observations?

  1. 2009/04/08 at 02:36

    Apologies for any typos in the preceding … it’s late and been a long day!

    BTW, this is a great site!

  2. 2009/04/08 at 02:35

    “Runaway Greenhouse” … an impossibility for very long. Runaway (as in “out of control, … rising rapidly” applied to the misnamed “Greenhouse” effect suggests temperatures rising rapidly out of control … forever. Obviously, if rising temperatures abated and temperature stabilized, then there is no “runaway” … and … if the rising temperature continued, then it would reach a point where whatever substance were being heated would melt/vaporize!

    Of course, none of the “true believers” can suggest how CO2 in the Venus atmosphere came to increase rapidly to cause even a temporary “runaway” effect.

    But the best part is the clear exposure of the temperature caused by the shear weight of Venus’ atmosphere, regardless of its constituents.

    What alarmists fail to comprehend is the differing roles of “greenhouse” gases and the forces that cause climate change. Earth’s greenhouse gases contribute to the background atmospheric warmth that creates an environment suitable for life on Earth within a range of temperatures consistent with the heat retention capacity of those gases. However, climate change is an entirely different beast … and “palaeoclimatology does not show any causal link between greenhouse gases and temperature” (M. Leroux, “Global Warming, Myth or Reality – The Erring Ways of Climatology”).

    It is scientifically illiterate to believe that suddenly, in the latter 20th Century, the entire history of climatology on Earth should suddenly be changed by the addition of another 15-20 ppm (0.0015% to 0.002%) of atmospheric CO2 (that is the amount added by human activity, according to the best estimates).

    Because CO2 has a residency in the atmosphere of about 5 years (+/- 3 years … it varies), and because water vapor is responsible for the vast portion (~95% in most inhabited latitudes) of greenhouse gas heat retention, and because the ability of additional CO2 added to the atmosphere to provide additional atmospheric heat retention declines logarithmically as more CO2 is added to the atmosphere, it is clear that the AGW theory based on the greenhouse effect of fossil fuel’s CO2 byproduct is absurd on its face.

    The fact that not a single study has ever been performed that identifies how much warming is due to human-generated CO2 from fossil fuels suggests that such a study cannot be performed because the underlying assumption is invalid (that human produced CO2 can change climate “catastrophically”).

    Where has all the sanity gone? Perhaps … up in smoke at the end of a pipe?

  3. 2008/03/04 at 01:31

    Now that you have done Venus, how about Mars? (I’d do it myself but my degree’s in a liberal art and they didn’t expect us to know much math.)

  1. 2010/05/07 at 21:52
  2. 2009/11/09 at 22:59
  3. 2008/03/08 at 11:48
  4. 2008/03/06 at 00:23
  5. 2008/03/02 at 21:30

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