A CO2 Concentration Problem
A popular current scientific model claims that climate change is being induced by global warming mediated by increased greenhouse gases. Advocates commonly identify greenhouse gases as causing atmospheric heating by absorption of infrared photons radiating from the Earthís surface. Atmospheric temperature rises and changes the weather. Cold air can hold little water vapor, the most important greenhouse gas. If greenhouse gases heated the atmosphere directly, water vapor concentration should rise, setting up further warming. Lack of atmospheric warming by greenhouse gases is also supported by the adiabatic nature of dry, dust-free troposphere. It expands and cools when it rises and compresses and warms when it falls without change in its energy content.
Many scientists are well aware of the lack of local heating but point to the spectral reduction in infrared radiation detectable by orbiting satellites. Water vapor and clouds play the largest reduction roles and an ozone-mediated loss is clearly seen. Carbon dioxide is responsible for a larger loss than ozone, but its rising concentrationís contribution to this reduction is disputed.
The use of the term global warming generates the most confusion. Measurements by polar orbiting satellites since 1978 indicate that temperature rise is predominantly in the Northern third of the Earthís troposphere. This strongly suggests that human activity plays a direct role since two thirds of humans live on this third of the planetís surface. But the carbon dioxide model argues that the entire planet should be warming. CO2 is rapidly spread into both hemispheres. If its rising concentration acted to reduce the Earthís infrared loss its effect should be global. Directly important is the unambiguous cooling of the south polar troposphere (60-85o South latitude) that has also been found. While South Polar carbon dioxide content has been rising its air has been cooling. Current CO2 infrared models offer no explanation for this. We should not presume that a reduction of atmospheric carbon dioxide will benefit the planetís weather until we understand both the Northern warming and Southern cooling.