‘Greenhouse Gases’: Three Impossible Outcomes
Written by Alan Siddons
A teacher in South Korea wrote to ask me for more information about global warming theory, to help his class. Below is an excerpt of my reply.
In regard to CO2 and global warming, the two have become so linked in the public mind that the warming mechanism itself (the Greenhouse Effect) is seldom referred to or discussed. Rather, it’s taken for granted. For a detailed explanation of this mechanism, then, I’d refer your students to MIT professor Richard Lindzen’s essay Greenhouse Effect.
In Lindzen’s piece your students will discover that the popular notion of the Greenhouse Effect differs from the accepted scientific explanation. The popular view has it that gases like carbon dioxide absorb and trap thermal radiation (infrared light), thus keeping the Earth warm by reducing its ability to release heat-rays to outer space.
In this view “greenhouse gases” function much like a blanket or winter clothing. As this infrared image suggests, after all, a body that’s inhibited from releasing heat-rays will cool off more slowly, which is the same as saying “will stay warmer.”
But here’s the snag: satellites report that the Earth emits to space the same amount of thermal energy as it receives from the sun. In other words, there is no evidence of radiative insulation, no physical sign of “greenhouse gases” acting like a heat-retaining blanket. An alternative understanding of the Greenhouse Effect is therefore demanded, which professor Lindzen’s essay provides.
How the model works:
The Earth absorbs, on average, about 239 watts per square meter (W/m²) of sunlight and,
emits the same average intensity of heat-rays outward. But
due to an atmospheric layer (composed of “greenhouse gases”) that absorbs this energy, the sky reaches the same temperature as the Earth and
emits 239 W/m² in both directions, i.e., outward to space and inward to Earth.
Exposed to this second 239 W/m² light source, then, the Earth’s surface reaches a higher temperature.
This is the Greenhouse Effect that climate experts talk about. As a growing number of scientists are recognizing, though, such a heating mechanism depends on three impossible outcomes.
First, take a closer look at the emission from that two-sided atmospheric layer. In actual fact, when a given intensity of light (watts per square meter) is absorbed by a plane that’s free to release this energy from both of its surfaces, the emission from each surface is cut in half. In other words, a 1 square meter plane releasing the energy of 1 W/m² will radiate half a watt from one side and half a watt from the other — not 1 watt from each side! Otherwise, two watts would be emitted for each watt absorbed.
The section I’ve highlighted in blue describes the radiative response of a fully-absorptive flat plate. With a radiant barrier affixed to its backside, the 1-s plate can only radiate in one direction. Stimulated by a 1367 W/m² light beam, then, this one-sided surface responds with a 1367 W/m² infrared emission, a 100% return. The same plate without a radiant barrier (2-s) is able to radiate from both surfaces, however. So, having twice the area to radiate with, it yields only a 50% response from each side.
As you see, it’s simply a matter of dilution: the same bundle of energy has been spread over a larger surface area. Please observe that a larger area of emission also prevents the two-sided plate from getting as warm as a single surface target. In short, the standard greenhouse diagram depicts a two-sided atmospheric layer that is impossibly warm and radiating an impossibly large amount of energy.
Now for the second impossible outcome. Even if that hovering greenhouse layer did match the temperature of the surface whose radiation it is responding to, its own radiation would be unable to raise the surface’s temperature… for the simple fact that its temperature is the SAME as the surface. It is an axiom of physics that heat is only transferred when a temperature difference exists. Since the diagram has a minus 18° body (the greenhouse layer) facing a minus 18° body (the surface), therefore, neither body can make the other reach a higher temperature.
It shouldn’t come as a surprise, moreover, that no one has ever demonstrated (let alone explained) how body X, which is as warm as body Y, can manage to raise the temperature of Y… while the now-warmer Y cannot manage to raise the temperature of X, even though thermal law dictates that it HAS TO because a temperature difference now exists.
Which leads to Impossible Outcome 3. In greenhouse physics, the sky responds to the surface by matching its temperature and emission. The surface then responds to the sky by getting warmer and radiating twice as much as it would without the influence of “greenhouse gases.” But then, why is it that these gases cease to respond to the surface’s higher temperature and emission? Facing a body that’s radiating 478 W/m², this infrared-absorbing layer should supposedly stay in character and radiate 478 W/m² back to the surface and another 478 W/m² out to space. Yet it stubbornly remains at -18° although the surface it responds to has reached 30°.
Well, that’s three impossible outcomes too many. The theory of the Greenhouse Effect utterly lacks scientific merit. I do hope, then, that the considerations I’ve outlined will stimulate debate among your students and elicit some honest doubt about what many authorities have called “a settled science.”
Tags: Alan Siddons, David Archer, Derek Alker, European Space Agency, Gavin Schmidt, greenhouse gas theory, richard lindzen