Quote[/b] (The "Ozone hole" Controversy @ Chapter 2, page 28 in science textbook; ISBN=?)]
in the late 1980s, a few scientists and environmentalists announced the discovery of a "hole" in the ozone layer over the south pole. the environmentalists claimed that it was caused by a worldwide depletion of the ozone layer and predicted drastic increases in UV radiation. they blamed the depletion on man made chemicals called chlorofluorocarbons [CFS's] such as the well known refrigerants called freons and the fire extinguishing gases known as halons. according to the environmentalists, CFS's that escape into the atmosphere drift up into the ozone layer, where they are broken down sunlight into chlorine and other compounds. Certain forms of chlorine can change 2 molecules of O3 into 3 molecules of O2, resulting in a decrease in ozone and an increase in oxygen. Environmentalists called for a worldwide ban on CFC's, warning that millions of people would die if drastic actions were not taken.
in response to their outcry, world leaders, including British prime minister Margaret thatcher and president George bush, hastily signed the Montreal-London protocol, which called for the elimination of all CFC production by the year 2000 (2010 for third world nations)
. In 1992 president bush announced that CFC production in the US would be halted in 1995, 5 years ahead of schedule.
Unfortunately, there is yet no good substitute for these chemicals; proposed replacements are either toxic, flammable, or extremely expensive. The cost of converting from CFC's to replacements may reach $5 trillion worldwide many developing nations may not be able to afford the cost of conversion, but without refrigeration, food poisoning and starvation could claim millions of lives in those countries.
The ozone hole is actually a thinning of the ozone layer rather than a hole and appears to be a natural phenomenon.
Was the supposed threat of ozone depletion worth the cost of outlawing CFC's? the environmentalists say that it was, but what they did NOT say casts much doubt on the truth of CFC related ozone depletion.
The hole was first discovered in 1956, before CFC's came into widespread use. The scientist who first discovered the hole, dr. Gordon dobson, concluded that it was a natural phenomenon that appeared annually near the end of winter, lasted three to five weeks, and then vanished suddenly with the onset of spring.
The hole is confined to Antarctica. scientists who studied the hole in the 1950s concluded that it is caused by an Antarctic high altitude weather phenomenon called the polar vortex, noting that the hole appears and disappears with the vortex,. the north polar region, which lacks the vortex, has never developed an ozone "hole"
The hole is not a hole. The ozone hole is actually a thinning of the ozone layer rather than an actual hole. the lowest ozone concentration ever recorded in the hole was about 30% of the normal level, but levels this low are rare. Even when ozone levels are reduced, UVC absorption by O2 molecules (producing ozone) continues unabated.
Worldwide ozone levels are actually INCREASING as you read this. average ozone levels are higher right now then they were in 1962, even though CFC production reached a maximum in 1974. average ozone concentrations have been rising about 0.30% per year since 1986. measurements taken by the national cancer institute showed that between 1974 and 1985, the amount of UVB radiation penetrating the ozone layer declined by about 0.7% each year! a European study indicated a decrease of up to 0.9% in UV radiation reaching the surface between 1968 and 1982.
Man's production of chlorine containing compounds is insignificant compared to nature's. If every molecule of CFCs produced by man drifted up into the atmosphere and released its chlorine, man would have added about 750,000 tons of chlorine to the atmosphere during the peak year of CFC production. The oceans ALONE put 600 MILLION tons of chlorine (from sea salt) into the atmosphere every year, and volcanoes have been known to contribute over 200 million tons in a SINGLE ERUPTION (Mount Tambora) Even nonviolent volcanoes such as Mount Erebus in Antarctica, contribute to the total; Erebus has been pumping over 360,000 tons of chlorine into the atmosphere every single year since 1972. Other natural sources of atmospheric chlorine contribute an additional 13.4 million tons annually.
Nature contributes far mote chlorine to the atmosphere than man does.
The worst case ozone depletion scenarios of the environmentalists are insignificant compared to daily variations due to changes in the weather, solar activity, and latitude. Variations in solar UV output and the changing seasons of the year strongly effect ozone levels. ozone concentrations in portions of the ozone layer can fluctuate weekly by 40%, but this does not endanger life on the earths surface. Ozone levels also fluctuate year by year; by 20-40%, and ultraviolet exposure increases 50% for every 250 miles you move closer to the equator. The "global disaster" that environmentalists predicted was a decrease in average ozone levels BY LESS THAN 10% OVER THE NEXT 100 YEARS.
The Montreal-London protocol seems to have been based on hysteria, faulty science, and hasty conclusions. Unfortunately, we are now stuck with its consequences, but we can learn from its example. We are responsible to be good stewards of the planet God has given us, and being good stewards means taking care of our environment however, our decisions should BE BASED not ON PANIC AND HASTY JUDGMENT, but on SOUND SCIENCE AND COMMON SENSE.
Atmospheric Sources of Clorine* (millions of tons per year)
Oceanic Evaporation : 600.0
Volcanoes : 36.0
Burning of organic substances : 8.4
Plankton : 5.0
Total Natural Sources : 649.4
Chlorine in man made CFC's : 0.75
Chlorine theoretically released by the alleged breakup of man made CFC's : 0.0075
*Adapted from Rogelio A. Maduro and Ralf Schauerhammer, "The Holes in the Ozone Scare" (Washington D.C.: 21st Century Science Associates), 12.