In her letter published June 26, Danielle Holliday has confused two quite distinct atmospheric problems consequent to human activity. As I have found this confusion to be fairly common, it may be worthwhile to take a moment to straighten out some of the misconceptions in her letter.
The ozone layer consists of a region of the atmosphere between 15 and 35 kilometers above the surface in which the relative concentration of triatomic oxygen, ozone, is greater than at lower altitudes.
This increase is thought to occur as a consequence of interaction between “normal” diatomic oxygen molecules and ultraviolet solar radiation. The ozone molecules produced are particularly good at absorbing the shorter wavelength ultraviolet radiation and keeping it from reaching the surface, where they would cause an increase in cataracts of the eye, sunburn, and skin cancer.
Ozone depletion is a problem first noticed in the late 1970”s and was traced by atmospheric chemists to chlorofluorocarbon molecules, CFCs, such as Freon, acting as catalysts to convert ozone back into diatomic oxygen. CFCs are all of human origin, not occurring in the natural world.
Global warming is an effect caused by the release into the atmosphere of “greenhouse gases” like carbon dioxide and methane. Greenhouse gases are transparent to incoming visible solar radiation, but absorb and reradiate longer wavelength infrared radiation produced by the sun-heated surface. More thermal energy stays near the surface, so temperatures increase.
Carbon atoms that have been locked up in petroleum and coal for millions of years are released after being combined with oxygen to produce carbon dioxide in the combustion process. Once again, humans are the agents of change as we burn these fossil fuels as a source of energy. Some scientist project that our current global warming woes are minor compared to what may happen should we decide to exploit the vast quantities of methyl hydrate, so-called “methane ice” now trapped in cold, deep ocean water.
There are some linkages between these two problems, for instance CFCs are “greenhouse gases”, but, for the most part, these problems are independent of one another.
The concern expressed about the Sun”s hydrogen becoming a combustion hazard in Earth”s atmosphere is without scientific foundation.
I yield to Ms. Holliday any expertise concerning the prophecies of the Book of Revelation.
Steve Harness
Upper Lake
