Proactive protection from above

By | Science & Technology
NASA continually monitors the level of ozone in the Earth's stratosphere. Credit@NASA.

Taking effective action to address environmental issues may produce productive, measurable results. This appears to be the case for the restoration of the Earth’s ozone layer. Last week a UN panel reported that the level of ozone was showing signs of increasing in the Earth’s atmosphere, since the signing of the Montreal Protocol in 1987. Through scientific knowledge, politicians and researchers appear to have brought about effective solutions in order to restore the ozone layer to natural levels.

The ozone layer is a region of the Earth’s stratosphere (around 6 – 30 miles above the Earth’s surface) made up of O3 molecules – that is, three oxygen atoms bonded together. Oxygen, in this form, shields the Earth’s surface from UV radiation by absorbing its energy. When this energy is absorbed the O3 molecule is separated into an O2 molecule and a single oxygen atom. These then reform back into an O3 molecule and the cycle continues, forming a cyclic, protective layer of ozone in the stratosphere. This UV shielding effect has allowed life to evolve.

Twenty seven years ago governments from around the world signed the Montreal Protocol. This was an international treaty designed to regulate the release of clorofluorocarbons (CFCs). CFCs were used most commonly as refrigerants, propellants (in aerosols) and as a number of solvents. Through scientific research it was discovered that CFCs reacted with the ozone layer causing a hole to form in the stratosphere. This connection between CFCs and the ozone hole was first made in 1974 by Sherry Rowland and Mario Molina. The evidence mounted, showing CFCs direct effect on the level of ozone in the stratosphere, especially over Antarctica. The Montreal Protocol was therefore designed to control the production of CFCs, in order to allow nature to increase levels of ozone. Since the initial signing of the treaty in 1987, gradually more countries have been involved, and control of CFC release has vastly improved. Safer, more environmentally friendly, alternatives to CFCs have been developed. Former UN General Secretary, Kofi Annan, described the protocol as likely the most successful international agreement ever signed.

Diagram of the cylic ozone reaction in the stratosphere. Credit@Alun009

Diagram of the cyclic ozone reaction in the
stratosphere. Credit@Alun009

During this period of discovery, it was also found that Nitrous oxide was affecting the levels of ozone in the stratosphere. Nitrous oxide is most commonly produced by automobiles. Technological innovation brought about the development of the catalytic convertor, which is now used by all automobiles to convert nitrous oxide into a safer form. Developing alternative CFCs and catalytic convertor technology may continue to allow ozone levels to naturally increase.

Tracking the level of ozone from 1987, when the treaty was signed, to present day, has provided scientists with a graph demonstrating the effectiveness of the Montreal Protocol. The results show a gradual levelling off of ozone since the treaty, and from the year 2000, signs of gradual recovery.  According to NASA, if countries continue to follow the Montreal protocol then the level of ozone, across most of the globe, might recover by 2050. This is expected as CFCs remain active in the stratosphere for long periods of time.

In order to learn from them, it is important to monitor whether environmental regulations are having the desired effect. The Montreal Protocol shows clear signs of success, demonstrating that productive governmental support, backed by scientific data, may yield an effective response. This message may be carried forward in an effort to help protect the current climate. Governments and scientists may combine political influence and technological advances to design further, effective, protocols.  Continuing to take action is vital for environmental conservation.

How might governments apply this success to other areas of environmental protection?


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