In his attempt to give scientific justification to the global warming scare (Basic science explains why we must cut our emissions
, January 24), Mark Swanepoel ignores the fundamental scientific reasons why rising carbon dioxide (CO² ) is not causing, and cannot cause, dangerous climate change.
The Earth cools itself mainly by emitting infrared radiation into space. Greenhouse gases reduce this cooling.
CO² , a weak greenhouse gas, has only one significant absorption band for this infrared, at 15 micron. But the band is already saturated. All of the 15 micron radiation leaving the Earth’s surface is already absorbed. So adding more CO² has a small and diminishing effect (lowering the height of absorption and slightly increasing it in the shoulders of the band).
Standard radiation heat transfer shows that the direct effect of doubling the amount of CO² in the air from present levels (390 parts per million, or ppm) would increase the global temperature about 1°C.
However, there would be feedback (response to change) and it would be negative (countering the change), and so the actual temperature increase would be much less than 1°C.
All observation and records confirms this, and this is consistent with satellite measurements.