**Take Our World Back**

September 30, 2013

There is no denying that the atmospheres of Earth and Venus are responsible for a “greenhouse effect” that raises their surface temperatures significantly above their black body or effective temperatures. However, claims by anthropogenic global warming (AGW) alarmists about excess CO2 being responsible for temperature anomalies in the order of 1 °C are contradicted by the fact that Mars has more CO2 than Earth, but has no greenhouse effect.

**The Inner Planets Data**

Data is mostly sourced from NASA. The solar irradiance at 1 astronomical unit (AU) from the Sun is taken as 1,366 W/m2, from World Radiation Center measurements. For the other orbital radii of Mercury, Venus and Mars, an inverse square law adjustment is applied. Since we want to obtain the average solar flux received over the entire planet’s surface as opposed to at some point where the Sun is directly overhead, the figure is then divided by four, being the ratio of the surface area of a sphere to its cross-section. In order to obtain the absorbed radiation after allowing for reflected sunlight, the solar irradiance per square meter of the planet’s surface is multiplied by a factor of one minus its Bond albedo. The effective temperature, i.e., the temperature of a black body emitting the same flux as the absorbed radiation and hence in thermal equilibrium, is calculated from the Stefan Boltzmann law according to:

T = [Pd / σ]1/4 where T is the absolute temperature (K), Pd is the flux or power density (W/m2), and σ is the Stefan-Boltzmann constant of 5.6703×10-8 W/m2.K4.

Mercury’s atmosphere is essentially a vacuum, and so the mean surface temperature equals the effective temperature, although there is of course a large difference between the sun-facing side and the regions experiencing a long night. For the next three planets, it may be seen that the excess temperature over the effective temperature is more strongly correlated with the quantity of all atmospheric gases, or with the nitrogen, rather than the so-called greenhouse gases CO2 or H2O. At 210 K, Mars has the same mean surface temperature as its effective or black body temperature. Yet it has 167.6 kg/m2 of CO2, which is 28.1 times the 5.96 kg/m2 for Earth, which has an excess temperature of some 34 K or 13.3% over its black body temperature. But Venus has 1,021,000 kg/m2 of CO2, which is 171,000 times the value for Earth, whilst the surface temperature of Venus is 737 K, which is 4 times its black body temperature.

The proportions of each gas are generally quoted by volume, so these values were adjusted by a factor comparing the molecular mass of the gas with the molecular mass of the planet’s atmosphere, to find the mass quantity for each gas. Water vapor on Earth is reckoned to average about 1% by volume albeit highly variable, whereas H2O has a molecular weight of 20.04 compared to the average MW of 28.97 for Earth’s air, so the mass fraction is taken as 0.69%.