One of the many problems with the Catastrophic Anthropogenic Global Warming theory–now disguised under the anodyne title of “climate change,” which includes both drought and floods, among other things–is that the impact of a greenhouse gas like CO2 on the Earth’s temperature is logarithmic. That is to say, the effect is largest with the first molecules of CO2, and diminishes as the concentration of CO2 in the atmosphere grows.
The principle is simple: CO2 warms the atmosphere, slightly, because it absorbs radiation that is otherwise escaping from the atmosphere within a certain frequency. The more molecules of CO2 that are added to the atmosphere, the greater the chance that radiation emanating from the Earth has already encountered a CO2 molecule along the way, and the relevant frequency has already been absorbed. At some point, adding more CO2 has no impact on global temperatures. It is widely thought, I believe, that the large majority of whatever change might be brought about by increasing concentrations of CO2 has already been achieved.
That is the context for these observations from the Science and Environmental Policy Project’s The Week That Was:
Greenhouse gases absorb and re-emit infrared radiation in specific wavelengths (absorption bands). Widths [Note: The band is (say) 12 to 18 microns; the bandwidth is 6 microns.] For example, carbon dioxide has three main bandwidths of infrared absorption – 1.8 to 2 microns; 4 to 5 microns; and 12 to 18 microns, this last being the one that can block IR emanating from the surface. If 99% + of the infrared energy for a particular band width is interfered with by existing greenhouse gases, then the band is said to be “saturated,” and the energy is released at the top of the atmosphere, where there are no molecules of greenhouse gas to interfere with it.
Using computer simulations from HITRAN (high-resolution transmission molecular absorption database), developed at the Atomic and Molecular Physics Division, Harvard-Smithsonian Center for Astrophysics under the direction of Dr. Iouli E. Gordon, the next TWTW (dated June 15) will begin to discuss how existing carbon dioxide and existing water vapor in the atmosphere reduce the ability of additional carbon dioxide to interfere with outgoing infrared radiation because the absorption bands are already saturated. As one scientist stated: “the glass is already on this greenhouse – another layer has little to do.”
We will continue to monitor this issue. I suspect that the logarithmic nature of CO2’s impact on the climate is one of several reasons why the models that are the sole basis for climate hysteria have proven to be wrong.