It is commonly claimed that the Earth can be treated as a black body which is in equilibrium with the incoming radiation of the sun and the outgoing radiation into space from the black body Earth. Calculations based on this simple model indicate the Earth has an average temperature 33C warmer than it should be. It is said to be this much warmer due to its atmosphere, in particular due to water vapor primarily and other greenhouse gases such as CO2 secondarily.
A black body absorbs 100% of the energy that falls upon it and it re-emits energy based on the Stefan-Boltzmann formula. When the black body is in thermal equilibrium, it emits energy at the same rate as energy is absorbed. The theory assumes the outer surface of the black body is extremely thin, though this matters little to the calculation provided the underlying material has a fixed temperature gradient with the maximum temperature on the outside surface and a radiation absorption length which is extremely short. For the surface depth to be unimportant, the amount of radiation falling on the surface should also not be changing in time.
These are not conditions satisfied by the moon or the Earth. The moon surface heats up when radiation from the sun is incident upon it and that heat is conducted downward into the rock and dust of the moon surface. The local topography of the surface, the distribution of rock and dust minerals, and the local particle sizes will all affect the local depth to which heat will penetrate, the absorptivity of the surface, and the emissivity of the surface. In addition, the moon rotates so that the amount of energy from the sun, or reflected from Earth, varies over time upon a given area. Thus, the gradient of energy below the surface will change as the surface cools when sunlight is not incident on it. This sub-surface heat reservoir acts to warm the surface. This introduces a heat convection source, which is not consistent with a black body radiation source.
The situation with the Earth is much worse. All of the problems of the moon exist for the Earth. To which are added the fact that the Earth has a substantial atmosphere in which the radiation absorption length is long. Large thermal gradients will exist in the atmosphere even if it were of uniform composition. It is not. The most important way in which is not is the wide variation of water vapor in it, and still worse, the wide variations in cloud cover. The absorptivity of the atmosphere for solar radiation varies from place to place, as does the emissivity. Compared to the moon, the Earth's surface also has a great variability in the important properties of absorptivity and emissivity from area to area. The South Pacific is different than the Rocky Mountains, Antarctica is different than the Great Plains, the Siberian tundra is different than the Sahara or the Amazon rain forest. These differences alone would create great flows of heat in convection currents even if the Earth did not rotate. In addition, there is much more variation in the depth to which heat will be absorbed in the land areas than on the moon due to more varied compositions. Then, the oceans and water bodies hold very large amounts of energy which is absorbed to comparative large depths straight from incoming radiation and then further distributed in convection currents to great depths and over large lateral distances. All of these large heat flows on Earth cause it to fit the requirements of a black body radiator very poorly.
Let us return to the much simpler case of the moon. It has no atmosphere, no vegetation, and no oceans to muck things up. There is a paper by Martin Hertzberg, Hans Schreuder, and Alan Siddons called A Greenhouse Effect on the Moon?, which Dr. Hertzberg was kind enough to draw my attention to in early June and I have had in mind discussing its very important results ever since. The paper notes that NASA scientists needed to calculate the expected temperatures on the moon's surface prior to a landing. Taking into account the changing radiation on a point on the surface and assuming no heat was absorbed into the surface, the first result is:
When no radiation is incident upon the spot on the surface, the temperature falls to absolute zero! A later calculation took into account some light reflected from Earth when sunlight was not incident. Under that condition, the low temperature was between 30 and 40 Kelvin. But the moon does absorb heat for some depth into its surface and that heat flows to the outer surface as the outer surface cools at "night." So, what did NASA find the temperature profile over the course of day and night to be?
Because the Earth has an atmosphere and because it has oceans over 70% of its surface and the oceans retain huge reservoirs of heat, the variation in temperature throughout a day is much less on Earth than on the moon. But, there is still a rise in the average temperature due to heat convection on land, in the oceans, and in the atmosphere. Heat convection in 3-dimensions creates an effect that looks like the greenhouse effect. Similar effects are observed for all of the planets.
It appears that if any "greenhouse effect" occurs due to CO2 in our atmosphere, that effect is very small compared to the 3-dimensional effects of distributed heat with convection heat transfer. That this is so has long been known by NASA, which nonetheless has played a very major role in the promotion of AGW alarmism on the basis of greenhouse gases! Once again, we find that government is not worthy of our trust. It has promoted terrible damage to our economy on the basis of this greenhouse gas catastrophic warming nonsense. It has been willing to put companies and many employees out of business. It has been happy to promote programs for alternative energy that greatly increase our energy costs and threaten to degrade the quality of our energy systems in use. It has declared CO2 a pollutant and is about to start draconian regulations at great expense, with huge additions to the bureaucracy, and terrible hours of additional paperwork, expert fees, and lawyer fees for many, many companies. Cap and trade schemes have been put forth in its name which will enrich the politically connected, while the average family sees its energy bill go up between $1,700 and $3,500 a year. As Obama says, our energy costs will necessarily skyrocket.
Obama may be fine with skyrocketing energy costs, but you and I should be very angry about it. Not only is the basis in CO2 greenhouse gas theory all wrong, but none of the remediation schemes are even thought likely to benefit the climate in any significant way. Even if the greenhouse effect were substantial, which it is not, all of the energy use restrictions are all pain and no gain. Are we all suddenly masochists? Don't we all have lives to live, places to go, and things we want to make or own? What is this madness that has overcome so many of us? Well, for some it is simple robbery. There are those who are very happy to take advantage of the fact that most people and most Americans in particular, do not know enough science to understand how badly the wool has been pulled over their eyes. There are no two ways about this. The catastrophic man-made global warming scare has been a massive fraud. There are many very evil people promoting this fraud and most of the impetus for it is coming from Democrats. It is very important to make them pay in the elections of 2010 and 2012.
Posts
