NAA: The Destruction of the Ozone Layer

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From: Chris Scheurweghs <scheurwe@stc.nato.int>

THE DESTRUCTION OF THE OZONE LAYER

Draft Special Report

Mr. Paolo RIANI (Italy) Special Rapporteur*

International Secretariat October 1995

* Until this document has been approved by the Scientific and Technical Committee, it represents only the views of the Rapporteur.

1. The existence of the climatic changes that have been taking place during the last few decades is no longer the subject of debate. The task today is to refine techniques that will enable increasingly urgent remedies to be found.

2. The composition of the Earth's atmosphere has changed over the past two centuries as a result of human activities. The advent of the Industrial Revolution led to ever-increasing consumption of fuel and a rising level of carbon dioxide in the atmosphere. Agro-industrial activities and increased energy consumption brought about a rise in methane and nitrous oxide levels.

3. Furthermore, since the 1950s, there has been a rise in the quantity of chlorine compounds in the atmosphere, as a result of the large-scale use of well-known compounds such as chlorofluorocarbons (CFCs). The effects of these variations are diverse: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N20) help to absorb infrared radiation and, as a result, to warm the Earth; others, such as the CFCs or other chlorinated compounds tend to destroy stratospheric ozone.

4. Recently, scientific research has shown that the depletion of ozone in the stratosphere caused by CFCs seems to contribute significantly to disruption of the upper atmosphere. There is less ozone to intercept solar radiation and re-radiate longer wavelengths on to the Earth's surface. If this finding is confirmed by further research, it would mean that the real effect of CFCs on global warming would be negligible or non-existent. This would not in any way obviate the need to eliminate CFCs, given the damage they do to the ozone layer.

5. The most striking change to the ozone layer is what is known as the ozone "hole" over the Antarctic. If the ozone layer's thickness in 1957 is compared with its thickness today, we find that the layer's density is constant practically everywhere except in the Antarctic polar region during the three months of the southern spring (September, October and November). Secular trends in the Antarctic show a constant decrease in density during the southern spring months, measured at about 300-320 Dobson units, in recent years. This means that the quantity of ozone normally present at these extreme latitudes during the spring has been halved, and is falling towards one-third of what it was.

6. This effect, though typically regional, ultimately causes small reductions in the ozone layer. Generally, a 5% depletion of the whole ozone layer at our latitudes causes an average rise of 10% in ultraviolet (UV) radiation intensity at ground level.

7. Also, as widely predicted by scientific models in recent years, the destruction of the ozone layer, which until recently only occurred during the southern spring months, now continues throughout the year and shows a very disturbing trend. Very recent observations by the British Antarctic Survey have revealed that, at the present rate of depletion, the ozone will have completely disappeared from the polar region by 2005.

8. The problem is magnified by the results observed in Europe and the United States. It is now beyond dispute that, with a 2 to 6% fall at medium latitudes in the northern hemisphere during the period from 1969 to 1986, depletion of the ozone layer is more than twice what was predicted and will in all probability quadruple by the end of the century.

9. It should also be remembered that, according to representative sampling, long-term trends on a wide geographical scale indicate a global fall not attributable to known natural processes.

10. Measures taken by health authorities in an effort to reduce exposure of the population to solar radiation, in both summer and winter, are now considered normal. The risks of diseases linked to the effects of UV radiation not filtered by the stratospheric ozone are rising steadily and disturbingly.

11. Scientific analyses of the hole in the ozone layer have alerted the international community and given rise to a first initiative; the Vienna Convention and the Protocol that followed, together with its amendments (Montreal, London, Nairobi and Copenhagen) have imposed significant reductions on the production and consumption of CFCs.

12. The present situation nevertheless calls for a number of negative comments on international commitments regarding ozone. The essentially pragmatic nature of the resolutions adopted in recent years during revision of the Montreal Protocol has clearly shown the inadequacy of the instruments of international cooperation to face up to the environmental priorities on a global scale.

13. Data in recent years have shown that the only really effective decision aimed at reducing destruction of the ozone layer is total elimination of CFCs, and that the gradual pace of international plans is being constantly outstripped by the overall situation.

14. It takes a very long time for CFCs to reach the stratosphere - about 7 years. The present situation results from the pollution before the 1980s. Owing to their chemical stability, CFCs remain in the atmosphere for about 100 years. This means that an immediate halt to emissions would not have significant effects for another century. Similarly, even very small emissions of CFCs will lead to a 6% overall depletion of the ozone layer and a 10-15% increase in UV radiation at ground level, with the consequences we know, over the next 50 years.

15. This is the great problem of global environment policy on which international organizations such as NATO must reflect. Special procedures must be defined for environmental intervention, so that no difficulties of implementation render scientifically-based decisions ineffective. If new forms of international cooperation do not emerge, it will only be possible to apply partial and ineffective remedies to problems such as climatic change.

16. The countries party to the Montreal Protocol have decided totally to eliminate chemical emissions harming the ozone layer by the year 2000, but that is not enough. While the producer industries are now replacing CFCs by other compounds and are thus seeing additional market niches opening up, there nevertheless remain difficult problems to solve.

17. CFC substitutes, consisting of molecules very similar to those of chlorofluorocarbons, cost 6 to 7 times as much. The Third World countries are not in a position today to take on the necessary technological change. Also, on account of their legitimate tendency to increase consumption and their low technological level, those countries are causing a general increase in atmospheric pollution.

18. The economic support programmes launched in recent years, and the delay in their implementation, clearly show the enormous gap between the scale of the problem and the weakness of the resources employed. While the NATO countries are still significantly committed, the current situation nonetheless shows that international cooperation policies are inadequate overall.

19. Environment policy experts assert that, in order to be effective, the steps taken to combat atmospheric pollution must form part of exhaustive forecasting systems, taking account of demographic trends, the economy and technological status of countries, in order to set significant objectives. And while this consideration concerns the more general problem of the greenhouse effect, it is still more significant for the destruction of the ozone layer, for this man-made damage is also direct and immediate, whereas the solution to the problem seems a long way off.

20. Article 3 of the Framework Convention on Climate Change, signed in Rio in June 1992, states that "the Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities". Although it is only a basic principle necessitating implementing protocols, this declaration contains the key to solving environmental problems because it modulates the solutions according to structural differences and political realities. The same path must be followed in regard to the ozone problem.