Ozone Depletion and Restoration

Previous article in this series: March 15, 2016, p. 278.

In the late 1800s and early 1900s, highly toxic gases, such as ammonia, methyl chloride, and sulfur dioxide, were used as refrigerants. Due to their toxicity and a number of fatalities in connection with leaks of these chemicals, they were replaced by chlorofluorocarbons (CFCs)—laboratory-built compounds composed of carbon, hydrogen, fluorine, and chlorine atoms. In 1928, Thomas Midgley, Jr. from General Motors synthesized the first CFCs. By 1930, Dupont and General Motors were cooperatively producing Freon (Dupont’s trademark name for CFCs) in large quantities. Freon was a nontoxic, nonflammable substance that could be used in a number of industries. Soon Freon was widely used as a propellent in spray cans and as a refrigerant coolant. In the 1950s and 1960s Freon paved an inexpensive way to bring air-conditioning to automobiles, homes, and offices.1

However, in 1974 chemists discovered discouraging news regarding CFCs. While the chemical appeared to be harmless at ground levels, its presence in the upper atmosphere told a different story. It was discovered that the CFC molecules played a role in depletion of the ozone layer. (At this point, it should be noted that the issue of ozone depletion is a separate issue from the more popular global-warming or climate-change issue. Sometimes the two are confused or connections between the two are made that ought not be made.) More specifically, it was discovered that ultraviolet (UV) light reacted with CFCs, causing chlorine atoms to be “knocked off ” the CFC molecules. This was concerning because some of the freed chlorine atoms reacted with ozone, breaking down the ozone molecules (O3) into diatomic oxygen gas (O2) and single oxygen atoms (O), thus gradually depleting the ozone layer that filters harmful UV-B rays. As we noted in our previous article, the unfiltered UV-B can cause many biological problems, particularly in plants and humans (skin cancer).

While it is true that the freed chlorine atoms, released from the CFC molecules, break down the ozone molecules, eventually many of the freed chlorine atoms became inactivated when they combine with other molecules. Due to this inactivating process, ozone depletion is minimized around the globe, with the exception of the polar regions.

Scientific research has shown that while the source of most CFC molecules is found far from the Antarctic, they are, nevertheless, carried around the globe in the various air currents, and eventually are also found above the Antarctic. Throughout the 1980s and 1990s, along with an increase in CFC concentration, a noticeable change to the ozone layer above the Antarctic (70oS to 90oS latitude) was observed. The fact that there is more destruction of ozone in the polar regions than elsewhere around the globe is due to the unique chemical reactions that occur in the atmosphere in these areas. In the polar regions, especially in the southern hemisphere, very cold temperatures during the winter months cause the formation of tiny ice crystals in the atmosphere. On the surface of these ice crystals, various chemical reactions occur which free the “inactivated” chlorine atoms. While on the surface of the ice crystal, the freed chlorine atoms combine to form chlorine gas (Cl2), which then escapes the ice crystal and collects in the lower stratosphere. While in the chlorine gas form (Cl2), the chlorine atoms are still inactive. However, at the onset of Spring, when sunlight begins to appear for longer periods each day, the energy from the rays of the sun causes the Cl2 to split back into individual chlorine atoms. Since the ice crystals, which contain the molecules that would usually trap the free chlorine atoms, have slowly migrated to lower altitudes due to the influence of gravity, the chlorine atoms now react easily with ozone, breaking it down.2

Consequently, ozone depletion happens rapidly and in large amounts during the spring months (September and October) above the Antarctic. By mid-October the ozone hole is at its largest—covering an area the size of North America. By late Spring, the temperature has warmed sufficiently that the polar ice crystals in the atmosphere begin to melt. This has two significant effects. As the ice melts, the chlorine-inactivating compounds that were bound to the ice crystals at lower altitudes are now freed and migrate to higher altitudes, once again reacting with the freed chlorine atoms to form inert compounds. Secondly, since the surface of the ice crystals was necessary to free the chlorine from its inactivating compounds, with no more ice crystals, chlorine no longer has a way of being released from those compounds. Therefore, due to a lack of free chlorine atoms, the ozone-depletion stops until the coming Spring.

Because ozone depletion occurs to a large degree above the Antarctic in the spring months, those living in locations in the southern hemisphere can be exposed to a higher level of UV-B radiation. Although the inhabited locations of the southern hemisphere are a rather significant distance from the ozone hole above the Antarctic, scientists believe that UV-B penetration extends also to these locations. This is of particular concern for the fair skinned populations in Australia, who have less natural skin protection to UV-B rays.

Natural Ozone Repair

What is not ordinarily discussed with respect to the thinning of the ozone layer is the fact that there are, in God’s providence, means built into the creation by which ozone is generated and will actually repair the thinning of the ozone layer.

In the upper stratosphere, diatomic oxygen molecules (O2) break down into individual oxygen atoms (O) when hit by UV-C rays. Many of these individual oxygen atoms will eventually collide with another oxygen atom to create diatomic oxygen molecules once again. But in the middle to lower stratosphere, there is a higher concentration of diatomic oxygen molecules. In addition, there is a limited amount of UV-C that penetrates to these levels, producing a small number of individual oxygen atoms. Consequently, at lower stratospheric levels, individual oxygen atoms are more likely to collide with diatomic oxygen molecules to create ozone molecules (O3) than to collide with other individual oxygen atoms to make diatomic oxygen.

During daylight hours, therefore, ozone molecules are constantly being formed in the middle and lower stratosphere. This helps explain why an ozone hole that appears over the Antarctic in Spring not only stops growing but can slowly close through the summer and autumn months. However, what scientific research seems to have shown is that, over the years, the natural rate of ozone restoration lags behind the natural and artificial (CFC-caused) breakdown of ozone during the Spring. Consequently, a large hole in the ozone layer appears for several months each year.

This emphasizes the importance of reducing the release of chemicals that can destroy ozone molecules. In 1987, the Montreal Protocol—an international agreement on reducing CFC emissions—was signed by many nations (including U.S. President R. Reagan in 1988). The Montreal Protocol and subsequent revisions thereof have called for the gradual phasing out of various chlorine-based ozone-depleting substances. Many see the results of this agreement as promising, noting that since “the implementation of the gradual phase-out of ozone-depleting substances, the total tropospheric concentration of chlorine peaked in 1994, and had declined by about 10% by 2007.”3 Therefore, scientists predict that

the Antarctic ozone hole probably will not continue to appear after the middle of the twenty-first century, that is, once the chlorine equivalent concentration is reduced back to the 2 ppb [parts per billion] level it had in the years before the hole began to form [1979]. 4

There are those who have proposed that ozone-hole formation has occurred prior to scientific observations and is part of earth’s natural cycles, not directly the result of any man-made products. However, as it seems was the case in the Dust Bowl in the 1930s, environmental issues are usually the combination of many factors, including man’s use of the creation (unwise farming practices of the 1920s) and the creation’s natural cycles (droughts of the 1930s). Such is likely the case with the ozone also. For example, we know there are man-made chemicals that affect the ozone layer, but we also know there are natural fluctuations in the amount of UV rays that come to the earth from the sun, also affecting the ozone layer.

The point of this article is not to enter into the debates, but to lead us to contemplate two important truths. First, we are to contemplate the truth that the creation groans under the judgments of God, whether through His use of “natural” means or by means of man’s misuse of the creation. Secondly, and very importantly, we are to consider the truth that we are stewards of this creation and are to be encouraged in a wise and faithful use of it.

Signs of the Times— Groanings of the Creation

As has been demonstrated, misuse of the creation can lead to various consequences. Scientists are aware of a variety of environmental issues for which they seek solutions. What we need to be reminded of is that, though wicked man will try to alleviate the world of these issues, they will not ultimately succeed. God is bringing upon the world His plagues and judgments as we progress to the final end of all things. Wicked man refuses to acknowledge God’s judgments, but rather “blaspheme[s] the name of God, which hath power over these plagues: and…repent[s] not to give him glory” (Rev. 16:9). Wicked man in his impenitence tries in vain to stop the running of the four horses, the sounding of the trumpets, the opening of the seals, and the pouring out of the vials of God’s wrath. Without God, he vainly hopes to alleviate all troubles on the earth.

In the efforts of men to remedy the environmental troubles they have brought upon themselves through their wicked use of the creation, we must learn to see an attempt to rebel against the sovereign God who justly pours out the vials of His wrath upon the world. And although the world may make some apparent progress in this regard, especially as the antichristian kingdom develops, God will ultimately destroy this creation, “burning this old world with fire and flame, to cleanse it” (BC, Art. 37). Let us remember that the true and final relief of the curse is found only in the return of Jesus Christ, when all things will be made new in the new heavens and earth (cf. Rev. 21:1-5; Rom. 8:19-23; II Pet. 3:13).

Wise Use of the Creation

Although God is bringing about His just judgments upon the earth, our calling remains to be good stewards of this creation and not to misuse it or purposefully to waste or mistreat it. The fact that the creation will be “dissolved” (II Pet. 3:11) by God does not give us license to misuse or harm the creation. Rather, as this issue of ozone depletion reminds us, we have a calling to care for God’s creation. We must realize that we have an impact on this creation—perhaps not as drastic as some would have it, but an impact nonetheless. And without responsible use of God’s gifts within the creation, there are consequences. In this particular situation, the sudden increase of CFCs released into the atmosphere played a part in the thinning of the ozone layer. With a thinning of the ozone layer, more UV-B rays penetrate to groundlevel. This increase in UV-B at ground level may prove to be a major contributor to an increase in skin cancer rates for fair-skinned humans in North America, and more particularly in Australia, which is near the hole in the ozone layer that appears each Spring.

Each generation ought to consider the environmental issues of the day. This can be challenging. Biased media attention, often politically driven, sometimes sensationalizes or elevates a situation to immediate crisis level, often by manipulating the data to attain a desired perspective rather than presenting a fair and accurate description of the situation. This discourages our attention to these issues and creates distrust with regard to it. Also, because of the incredible complexity and interrelatedness of the creation, scientists struggle to determine accurately the effects of a particular environmental stimulus, further casting doubts in our minds of the validity or reality of an issue. Further, understanding that the apparent solutions to environmental issues may actually trigger an entirely new set of challenges, we nonetheless strive to study environmental issues, be aware of them, and properly engage in dialogue regarding them. We do all these things because we recognize our calling from God to be faithful stewards of all of His good gifts (Gen. 1:26-28; Gen. 2:15).

We care for the creation, not because we expect human life to last forever on this physical earth, or because we are motivated by humanistic reasons, but because we are called by God to care for it. The honor and glory of God and the good of the neighbor motivate us to strive consciously to be faithful in our use of the creation. Our desire is that the creation continue to show forth the beauty and majesty of the Creator (understanding its speech is affected by the curse) and that the creation may serve us so that we may serve God in it, in each of our callings, until Christ returns. May God give us wisdom and bless us in our use of His good gifts.


1 http://www.esrl.noaa.gov/gmd/hats/publictn/elkins/cfcs.html, accessed February 2, 2016.

2 Colin Baird and Michael Cann. Environmental Chemistry, 5th Ed. (New York: W. H. Freeman and Company, 2012), 41-45.

3 Colin and Cann. Environmental Chemistry, 63.

4 Ibid.