OZONE HOLES IN THE THEORY

For some two hundred years or more, the flux of energy from the sun per unit area and unit time (in watts per square meter) at the outer reaches of the terrestrial atmosphere was thought to be constant, and the corresponding value was therefore called the "solar constant."

But about a decade ago, a satellite called "Solar Max" reported otherwise. The solar constant was not constant at all: it fluctuated with flares and other phenomena on the ever turbulent sun, but these small fluctuations were damped out by the absorption (also small) of the atmosphere, so that they could not be observed on the earth.

Now comes news that the solar constant (renamed to "solar irradiance") not only fluctuates, but has declined perceptibly over the five years 1980-84 as measured by sophisticated equipment on board NASA spacecraft. ["Long-term downward trend in total solar irradiance" by R.C. Willison and others, Science, 11/28/86, pp. 1114-1117]. The decline amounts to almost 0.02% per year.

From what we know about the past climate on earth, it is quite out of the question that this decline is something that has been going on for a lengthy period (like a century or two). It is evidently part of a fluctuation: what has gone up is now coming down. The most obvious speculation (and it is only speculation) is that the changes are associated with the cycle of solar activity, which averages 11 years in length.

Most things in nature fluctuate, and the example of solar irradiance illustrates how other alleged trends may well be simply misunderstood fluctuations. In 1985 a hole in the ozone layer above the Antarctic was discovered, causing the Sunday supplements, egged on by irresponsible scientists, to lament the use of chlorofluorocarbons in refrigerators and, outside the US, as propellants in some spray cans.

But the theory is unproven and subject to criticism. Among the ozone holes in the theory is the incorrect assumption that if the present ozone layer were removed, the UV radiation would find nothing in the atmosphere to dissipate its energy on. It is also hard to swallow that the amounts of chlorofluorocarbons reaching the layer from human activity could compete with the gigantic natural forces at work: the variations of the ozone layer by latitude and season are larger than those predicted from human activity. It therefore seems quite conceivable that the observed changes in the ozone layer are, like those of the solar irradiance above, natural variations of unknown origin; but man in his conceit ascribes them to himself.

Nevertheless, the US has proposed to take steps preventing the depletion of the ozone layer, and as we go to press, international negotiations begin in Geneva, the US being represented by R.E. Benedick, the State Departments Deputy Assistant Secretary for Environment, Health, and Natural Resources (did you know there was such a thing?). The results, if any, will be insignificant, for the "environmentalists" in the US no longer have the clout to forbid chlorofluorocarbons in refrigerators, and in much of the rest of the world they don't even have it to forbid them in hair sprays.