The "Hole" in the Ozone Layer

Introduction
In February of 1992, the National Aeronautics of Space Administration (NASA) shocked the world by reporting that they had evidence of a hole in the ozone layer. As time went on, they backed up their report by showing many graphs of data.

The above image was taken on September 26, 1999, and as you can see this figure shows the concentration of ozone in the ozone layer over the southern hemisphere of the world on that date. The color bar below the figure is a legend indicating the ozone concentration level represented by the colors that you see on the graph. Ozone concentration is measured in a unit called the "Dobson unit". Notice that white and pink area in the middle of the graph. Centered directly over Antarctica, it represents an area of low ozone concentration.

This, ladies and gentlemen, is the "hole" that NASA found.

Why It Is There

In a series of very clever experiments, scientists eventually connected this decrease in ozone concentration to chlorine in the stratosphere. They found that under certain conditions, chlorine atoms can break ozone down into oxygen, and the found such chlorine atoms in the ozone layer above Antarctica.

Well, once scientists connected the "ozone hole" to chlorine, the next question became where did the chlorine come from? It turns out that there are many sources that will put chlorine into the stratosphere, but one source that got a lot of attention during the first panic was a class of substances called chlorofluorocarbons, or CFCs.

But What Are CFCs?

Before I get ahead of myself, I must explain what CFCs are. These substances are human-made, and turn out to be incredibly useful. The CFC known as "Freon", for example, is used in refrigeration and air conditioning. Other CFCs are used in surgical sterilizers, and still others are used as fire-fighting agents. In all of their applications, these chemicals are significantly more efficient than what was used before CFCs were invented.

But, not only are CFCs incredibly useful, they are also completely non-toxic. CFCs are so chemically inert that they do not react with our bodies or the bodies of animals. In fact, with the exception of certain microscopic organisms that tend to break CFCs down, these chemicals do not really interact with any living organisms. Since CFCs are so incredibly useful and at the same time non-toxic, they became very widely used in just a few years.

What Happened To CFCs

Since scientists linked the "ozone hole" to chlorine, and since they determined that at least some of this chlorine came from CFCs, many people immediately called for the elimination of CFCs. As a result, many world leaders signed a treaty called the "Montreal-London Protocol," which called for the elimination of CFC production by the year 2000 for industrialized countries and the year 2010 for developing countries. President George Bush actually required the United States to move ahead of the schedule, and CFC production in the U.S. was halted in 1995. Please note that "production" is different than "use". It is still legal to use CFCs in the U.S., but no one is allowed to make them any more. Eventually, then, we will run our of CFCs entirely, but we have not yet.

Will This Help?

Now that CFC production is eliminated in the U.S. and will soon be eliminated in other countries, lives will be saved, right? After all, if CFCs are destroying the ozone in the ozone layer, then the elimination of CFCs will be a good thing, right?

Believe it or not, the elimination of CFCs will result in a significantly larger loss of human life than if CFCs were not eliminated. If you were to do a cost/benefit analysis on the elimination of CFCs, you will see that the costs far outweigh the benefit.

The Cost/Benefit Analysis -

Lets start with the benefits of CFC elimination.

The Benefits

When CFCs are eliminated, the ozone hole will decrease, and lives will be saved, right? Not exactly. Remember, the "ozone hole" is caused by chlorine atoms under certain conditions. The important party of that phrase is "under certain conditions." You see, the "ozone hole" was actually discovered by Dobson (the scientist after whom the ozone concentration unit is named) back in 1956, before CFCs were being widely used. At that time, Dobson noted that the "hole" on the ozone layer appears over Antarctica each year from August to November. The "hole" then fills up again by November, bringing the ozone layer back to full strength.

First of all, it is important to realize that back when Dobson first discovered the "ozone hole," CFCs were not being widely used, as I said before. Thus, the "ozone hole" itself cannot be traced completely back to CFCs. It seems to be, in part, a natural phenomenon. It is also important to note, however, that over the years, the "hole" has gotten deeper and deeper. In other words, the concentration of ozone in the ozone layer over Antarctica during the months of August to November is significantly (about 20%) lower today than it was when Dobson first discovered the "ozone hole." Obviously, then, something has been happening to make the "ozone hole" worse than it used to be.

"Under Certain Conditions"

At the same time, however, the concentration of ozone in the ozone layer over Antarctica during the rest of the year has not changed. In other words, even though the "ozone hole" is deeper than it used to be, it is only deeper for about 3 and a half months out of the year. Once November passes, the ozone concentration returns to essentially the same level it has been since ozone levels have been measured. How can this be? Well, remember the phrase "under certain conditions?" That's the key. In early August of every year, a weather phenomenon known as the Polar Vortex occurs. In the Polar Vortex, winds blowing around the South Pole prevent warmer air from entering the South Pole region, and the result is constant low temperatures, as low as -90 degrees Celsius (-130 degrees Fahrenheit) and a steady rush of wind blowing upwards.

How It Works

Under the conditions of the Polar Vortex, water droplets freeze into tiny ice particles and the winds push them up into the stratosphere. If these tiny ice particles happen to have trapped any molecules that have chlorine atoms in them, and if those chlorine-containing molecules survive the tip up to the stratosphere, certain chemical reactions occur on the surface of the tiny molecules, and the result is chlorine that can destroy ozone. By November, however, the Polar Vortex is gone, and with it these conditions that produce ozone-destroying chlorine in the stratosphere.

In the end, then, the "ozone hole" is a seasonal phenomenon that happens only 4 months out of the year. Also, the "ozone hole" only appears over Antarctica, because that's the only place in the world where the Polar Vortex exists. The Polar Vortex doesn't even exist in the North Pole.

Now think about it. How many people are living in Antarctica? Not many! Thus, the CFC ban will reduce the depth of the ozone hole (it won't eliminate the ozone hole because it was there before CFCs were really popular) for four months of the year over a region of the world where very few people actually live. As a result, the ban on CFCs will not really save any lives. IN fact, not a single malady has ever been linked to the "ozone hole," so the elimination of CFCs will not even improve anyone's life!

The Costs

What about the costs of the CFC ban? Well, as I mentioned before, CFCs are the most efficient refrigerant, surgical sterilizers, and fire-fighting agents in the world. When they are completely banned, refrigeration, surgical sterilizers, and fire-fighting will be less efficient. As a result, people will die. There is question about that. Fires will last longer before they are put out, resulting in loss of property and death. Surgical procedures will be less sterile, causing more infection, which will cause sickness and death. Finally, refrigerators will be so inefficient that third-world food distribution will be reduced, resulting in starvation! Not only is starvation due to poor food distribution a concern, but so is food spoilage. Even one of the big supporters of the CFC ban (Robert Watson) has admitted that "... probably more people would die from food poisoning as a consequence of inadequate refrigeration than would die from the depleting ozone."

Misinformation

So what does our cost/benefit analysis tell us? The ban on CFCs will result in essentially no lives saved because of less seasonal ozone destruction, but it will certainly result in a significant loss of human life! Why in the world, then, did the Montreal-London Protocol get signed? Why have we already banned CFC production? Mostly because the people who make the laws are completely ignorant about real science. Unless you hear the whole story, it is very easy to be misinformed. If you ask any of the legislators who support a CFC ban, you will find that none of them know the details of the "ozone hole". As a result, they can be easily misinformed by those who are pushing some other agenda.

Please realize, though, that misinformation exists on both sides of the issue. Those who are against a CFC ban often quote the statistic that only 0.1% of all chlorine-containing molecules released into the atmosphere come from human-made sources. This statistic is true, but it is entirely irrelevant in the "ozone hole" debate. You see, the vast majority of chlorine-containing molecules cannot survive the trip up the Polar Vortex because most chlorine-containing molecules are so chemically-reactive that they tent to react with other substances in the atmosphere long before they reach the ozone layer. Because CFCs are relatively inert, they tent to survive the trip. As a result, human sources are responsible for about 81% of the chlorine in the ozone layer. Since the chlorine in the ozone layer is what is important in terms of ozone-destruction, 81% is the important statistic, not 0.1%.

As a sidelight, the reason that CFCs became so popular was that they were so efficient as certain tasks, and at the same time they were non-toxic. The reason CFCs are non-toxic is because they are relatively inert. Well, what makes it possible for CFCs to survive the long trip up to the ozone layer in the Polar Vortex? The fact that they are relatively inert. We see, then, an example of an unintended consequence. CFCs were hailed as a wonder chemical because they were useful and non-toxic. The same property that makes them non-toxic, however, also makes them great ozone destroyers.

The Result

In the end, then, the "ozone hole" situation is a great example of how poorly-educated our world leaders are in the sciences. Anyone with a rudimentary knowledge of science and an ability to do literature research could have easily found out the same facts that I'm telling you. However, because our leaders are so ignorant about these matters, legislation that will result in a tragic loss of life has been enacted. Hopefully students like us can change this situation in the years to come.

Before you leave this post, I want to dispel a very popular myth that is promoted by radical environmentalists. It is common for certain extremists to link ozone depletion to global warming. Hopefully, you now see that this is absurd. After all, the stratosphere is warmer than the tropopause because ozone is a greenhouse gas. If anything, then, ozone depletion will cool the earth, not warm it. Remember, however, that the "ozone hole" effect is so weak and so short-lived that there is really no effect at all. Nevertheless, if there were an effect, it would be opposite of what environmental extremists claim.