The "hole in the ozone layer" was first discovered in 1956, long before there was a big buzz about it.

Remember, it's called the ozone "layer" not the ozone "shield". That's because it is not a whole piece. Ozone is formed when sunlight hits oxygen. So wherever there's sunlight and oxygen, ozone is formed. Sunlight also breaks down ozone (i'll go into more detail later). So the ozone layer is constantly being broken down and regenerated. So the ozone we measure now is not the same as we measured before.

This "hole" in the ozone layer occurs every late winter in the Antarctic. Sometimes it happens to a greater extent than others. This all has to do with chlorine in the air, the temperature, and the fact that no sunlight reaches the south pole in winter to form ozone in the first place.

On September 16, 1987, a NASA ER-2 research aircraft measured a drop in ozone concentration and a rise in the levels of chlorine monoxide while in the stratospheric altitude above the Antarctic. Many groups like the EPA and NASA distorted this reading as proof that CFCs (chlorofluorocarbons) were destroying the ozone layer. They predicted mass cases of skin cancer causing millions of deaths and crop damage if CFC produciton was not halted. There was no evidence at all, though, that CFCs were doing any damage. The chief U.S. negotiator, Richard Benedick, in his book Ozone Diplomacy is quoted as saying "...the most extraordinary aspect of the treaty was the imposition os significant costs against unproven future dangers...dangers that rested on scientific theories rather than on firm data. At the time od the negotiations and signing no measurable evidence of damage existed." 13 years later, there is still no measurable evidence of damage.

The public was left with a distorted view of chlorofluorocarbons and the ozone layer.

Their theory was based on a fact, however. CFCs will break down in ultraviolet radiation and release reactive chlorine. The theory was that if the CFCs oculd be lifted into the air 10,000 meters where the level of UV would increase dramatically. CFCs would probably remain stable until they reached the onzone layer where it would be too vulnerable then break down and destroy the all-important ozone layer. It's a very unstable theory but that did not stop environmentalists. The case was most difficult for the defense which needed to prove that this does not happen. All the prosecution needed was a theory backed with highly emotional and exaggerated disaster scenarios.

When the ozone hole didn't show up during the winters of 1989 and 1992, the debate began to disentegrate but NASA came back in 1992 with new reports of high levels of chlorine in the north pole. Something that had never been seen before, an ozone hole in the arctic! But still, 8 years later there has never been an ozone hole in the north pole.

The ban on CFCs had planned to phase them out completely by 1992. Some say there was no hole because of that ban. That simply just doesn't work. The ozone doesn't change from year to year based on things that humans do. CFCs have a halflife of about a century!

The big problem the environmentalists and the public had was the "infamous, deadly UV rays". Well there are different kinds of UV rays. The shorter wavelength type, UVC, is responsible for splitting oxygen molecules, and creating billions of tons of ozone per second. The longer wavelength type, UVB, breaks it down. Both UVC and UVB are effectively blocked by the ozone layer. The longest wavelength, UVA, is not affected by oxygen or the ozone layer and passes through freely. Ironically, this is the wavelength proven to be the cause of melanoma, the deadly skin cancer.

Skin cancer was the main drive of environmentalists. And now, it is proven that the ozone layer has nothing to do with protecting us from cancer! Well, imagine if suddenly (magically), what we call the ozone layer, was completely eliminated. What would happen? More ozone would form immediately below it in the troposphere. Protective oxygen is always there, and it is the source of our ozone.

Our manmade materials have not have a true effect on the atmosphere. We would have to try really hard if we wanted to make a dent. So much more of this chlorine (which is the bad part in CFCs) occurs naturally than we make. A large volcanic blast can contribute 100 to 1000 million tons of active chlorine to the atmosphere, and a large portion of it may very well reach the stratosphere. Slower eruptions make a slow stream of chlorine, like Mount Erebus which has released 300,000 tons per year for the past 30 years Salt spray from oceans, forest and brush fires contribute an average of 700 million tons annually! All of these natural contributions add up to make a total four to five orders of magnitude greater than the man-made contribution. Also, take into fact that only a very minor portion of CFCs actually make into the stratosphere. The molecules are 4 to 8 times heavier than air and adhere easily to the ground and other things attached to the ground.

On a final note, remember that the first major hole in the ozone above the Antarctic (that we noticed) was in 1956, long before chlorofluorocarbons were in widespread use. This "hole" is a naturally occurring event that happens periodically.

Update: concerning the writeup below by mricicle, I do not trust the EPA. I would not rely on the facts that they give me. However, there is no way I can disprove them.
Sources: NASA (National Aeronautics and Space Administration) http://www.nasa.gov Global Warming in a Politically Correct Climate, M. Mihkel Mathiesen EPA (Environmental Protection Agency) http://www.epa.gov

After carefully reading the EPA web site, I find major contradictions with the facts in the above writeup by BigHoliday. Note that BigHoliday mentions EPA as source!

Facts from the EPA web site (http://www.epa.gov/ozone/) about the ozone hole:

  • There was no ozone hole in 1956. The EPA site refers to the British Atlantic Survey (BAS).

    See http://www.epa.gov/ozone/science/hole/holehome.html
    and http://www.nbs.ac.uk/public/icd/jds/ozone/history.html

  • The ozone layer DOES protect us from cancer:

    Laboratory and epidemiological studies demonstrate that UVB causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. In addition, UVB has been linked to cataracts. All sunlight contains some UVB, even with normal ozone levels. It is always important to limit exposure to the sun. However, ozone depletion will increase the amount of UVB, which will then increase the risk of health effects. Furthermore, UVB harms some crops, plastics and other materials, and certain types of marine life.

    Quote from http://www.epa.gov/ozone/science/sc_fact.html

  • Volcanoes are not the primary cause for ozone depletion:
    First, the vast majority of volcanic eruptions are too weak to reach the stratosphere, around 10 km above the surface. Thus, any HCl emitted in the eruption begins in the troposphere. Sea salt from the oceans is also released very low in the atmosphere. These compounds would have to remain airborne for 2-5 years to be carried to the stratosphere. However, both sea salt and HCl are extremely soluble in water, as opposed to CFCs which do not dissolve in water. Rain effectively scrubs the troposphere, removing both of these forms of chlorine. Steam in volcanic plumes can act the same way, removing HCl long before it reaches the ozone layer. Measurements have shown that concentrations of these substances vanish very rapidly as altitude increases. Neither sea salt from the oceans nor tropospheric-level volcanic eruptions (like Mt. Erebus in Antarctica) contribute significantly to stratospheric chlorine levels. Some sea life does produce methyl chloride, a more stable form of chlorine than sea salt, but its contribution is small, as explained below.

    CFCs, on the other hand, do not dissolve in rain. In addition, no chemical processes have been found that aggressively remove them from the troposphere. In fact, one of the advantages of the CFCs was their stability. However, it is this very stability that poses a threat to the ozone layer.

    Quote from http://www.epa.gov/ozone/science/volcano.html


All information was gathered on March 24, 2001 from:
EPA, http://www.epa.gov/ozone/science/
British Antarctic Survey Ozone, http://www.nbs.ac.uk/public/icd/jds/ozone/index.html

If you find any errors or inconsistencies in my writeup, please tell me immediately!

The hole in the ozone layer developed mainly due to high emissions of chlorofluorocarbons, or CFCs, which break into radicals in UV light, usually Cl radicals, which then react with ozone like so (' represents a radical):

Cl'(g) + O3(g) --> O2(g) + ClO'(g)
ClO'(g)+ 2O3(g) --> 2O2(g) + Cl'(g)

As you can see, one chlorine radical can theoretically break down an infinite amount of ozone, which is why it is so destructive. The only way to stop the reaction is if two radicals meet, and form a stable compound.

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