Much of the “global warming” confusion stems from conditions on the planet Venus- a planet about which little is known, but probes have successfully gathered some data.
The atmosphere of Venus has a high percentage of CO2 at very high pressure and extremely hot temperatures. At first glance, there may seem to be some correlation between high CO2 percentages and high atmospheric temperatures. However, the two conditions are unrelated.
Serious problems arise when equating conditions on Venus with potential future conditions on Earth. Venus evolved under completely different conditions than did Earth. Some of the evolution is very recent on the Solar System’s time scale. The only remaining similarity between Earth and Venus is planet size. Some of the many differences follow.
1) Venus has no moon and rotates about its axis very slowly. Subsequently, Venus cannot have
Earth’s level of tectonic activity or Earth’s level of magma flow. Even though internally molten, there is no reason to expect any significant magma flow inside Venus.
2) In the absence of tectonic activity, Venus has a minimal or actually, a zero measured magnetic field. The near-surface mantle is hot enough to exclude residual magnetism- hotter than the Curie temperature. Venus is even hotter toward its core. Without a magnetic field to deflect them, high-energy cosmic rays continually strike the surface of Venus and there is no protection from the eroding effects of solar wind.
3) Venus suffered a large impact and the impact’s substantial residual heat continues to dissipate into Venus’s atmosphere. Venus’s surface is much hotter than it could be due to solar energy especially with its continuously clouded condition and subsequent high albedo (reflectivity). The impact from less than 100,000 years ago heated all water into its gas state and solar wind rapidly swept it all away leaving Venus dry. However, Venus still has a great deal of atmosphere although much more exposed to Solar Wind than is Earth. This is indicative of a relatively recent impact since in the long-term Venus will have very little atmosphere.
4) Without surface water or vegetation, Venus has no means of storing away CO2; Venus has no carbon dioxide cycle.
5) Venus has no remaining condensable gases, gases such as water vapor that effectively transport heat from the planet’s surface to the outer reaches of its atmosphere; a complete absence of any gas operating in a refrigerant range; a temperature and pressure range allowing both condensation and evaporation.
6) Venus rotates very slowly; there are no significant Coriolis wind currents near its surface; a day on Venus is 243 Earth days.
7) There is very little wind at Venus’s surface, yet at high levels, global winds are strong enough to distribute the planet’s sunlit-side solar heat gains throughout its upper atmosphere. High atmospheric levels offer the only temperature differences that cause significant winds.
8) No part of Venus’s surface shows signs of erosion. The planet itself is the primary source of atmospheric heat. Since the surface heat is uniformly from the planet itself, there are no convection winds near the planet’s surface.
9) Venus is in closer proximity to the Sun’s energy than is Earth.
The maximum temperature that can occur on Venus due to insolation is far lower than its seven and eight hundred degrees Celsius surface temperature. A little warmer than Earth would be the temperature of Venus. To account for the temperature difference, one must assume that the planet’s surface is radiating the difference. This is at current albedo levels and at any atmospheric gas percentage and pressure.
CO2 has no magic means of holding heat. Any gas in non-condensable temperature ranges would have the same effect as CO2, which is, except for its pressure contribution, no real effect at all. On Venus, even CO2’s atmospheric pressure contribution has well exceeded its influence since at its high pressures, nothing on Venus exhibits a refrigerant cycle. Like all elements and compounds, CO2 heats up and cools off to match surrounding temperatures; atmospheric CO2 loses net stored heat in every cooler direction but always much more away from the planet it surrounds.
As to whether the mantle of Venus is hot relative to its atmosphere, the planet Mercury, even with its low albedo, is cooler than Venus during its daylight period (its hottest period), yet Mercury is much closer to the Sun than is Venus. There is an energy imbalance in the Venus System that is not attributable to gas percentages.
Venus has not yet cooled enough to have the major rifts and surface cracks that are inherent with the contraction of cooling rock. The cracks in a cooled basaltic surface might sum up to be in excess of 5 meters per kilometer in every direction on its surface and cracks would often be lumped together forming immense gorges. In fact, the
massive strike that made Venus hot occurred perhaps just outside Earth’s modern recorded history- 5 or 10 thousand years ago. Because of its visibly spectacular nature, a more recent occurrence would have been recorded in some fashion.
The heat emanating from the surface of Venus controls the temperature of the atmosphere of Venus- not the Sun. The Sun is merely supplemental heat. Atmospheric gases, including CO2, moderate temperatures at both Venus’s surface and Earth’s surface; they keep us cool in daylight and warm at night. Unlike Venus with its extremely high pressures, if anything is warming Earth’s surface, the rain cycle becomes more active overwhelmingly removing the added heat.