In the past, it was commonly believed that the ozone hole is a natural disaster caused by exhaust, fumes, and other environmental pollutants. Thus, scientists have predicted an imminent environmental catastrophe within a few years that would result in the destruction of the protective layer that shields Earth from harmful Sun radiations. However, a recently-emerging theory completely rejects the notion; instead, it confirms the existence of this hole for a long time, claiming it is a natural phenomenon that is not cause for concern. To present the two theories with proof and evidence, there are some facts that we need to understand about the ozone layer.
First, we need to comprehend that there is a difference between ozone gas and the ozone layer. Ozone is a poisonous blue gas composed of three oxygen atoms with the chemical symbol O3; it is used for medical purposes and in sterilization. The ozone shield is a protective layer composed of ozone gas; it is located in the stratosphere, the second layer of the atmosphere, approximately 25–30 km above the Earth’s surface. The main function of the ozone layer is shielding the Earth’s surface and living organisms from harmful Sun radiations, particularly Ultraviolet (UV) radiations. These harmful radiations cause blindness and skin cancer, kill some living organisms, and cause other environmental disasters. Yet, the ozone layer does not fully absorb the radiations; part of it reaches Earth.
In 1985, Britain sent an exploratory team to the South Pole; during the expedition, one scientist observed that the ozone level in this region was lower than in others. After several experiments and tests, scientist discovered the ozone hole; NASA later used its satellites to obtain more accurate information. The surprise was that the entire South Pole region suffers from ozone level depletion; another smaller hole was discovered in the North Pole. By monitoring the ozone hole, scientists noticed that the hole expands from September to December annually, and shrinks the rest of year.
When the ozone hole was discovered, scientists predicted an impending disaster; the serious expansion of the hole in the Earth’s shield protecting it from the Sun’s harmful rays, sooner or later, could kill all living organisms. Scientists have made great efforts researching the causes of this hole; after several studies and experiments, they have concluded that there are several factors, including:
- The emissions of Chlorofluorocarbons (CFCs), which are organic compounds, containing chlorine, carbon, and fluorine; they are known commercially as Freon, which is used in refrigerators and air conditioners.
- Exhaust fumes from cars and airplanes, factory smoke, and chemical wastes responsible for air pollution.
- Nuclear explosions, which have enormous destructive capabilities, in addition to the emission of radiations.
Given these causes, we find that most of them are emitted from vital and important resources of human life; thus, they were uncontainable. The only solution became limiting the use of these sources as much as possible, and trying to find clean alternatives, such as solar energy, wind power, and others.
Different Theory
Some scientists are inclined towards a completely different theory though; namely, that the ozone hole is a natural phenomenon that transpired since the formation of the ozone layer. As such, the ozone hole is harmless to living organisms and does not expand continuously; the scientists based their theory on several scientific and logical reasons, including:
- The ozone layer cannot be destroyed, but is renewed by the continuous formation of new ozone molecules.
- The existence of the ozone hole in the North Pole and South Pole; two of the least polluted regions in the world.
- The hole appears during a certain period of the year, specifically during the Polar spring, and then decreases gradually until it disappears totally during the Polar winter.
- Chlorine atoms, most of the exhausts, and Freon gas do not reach the upper atmosphere layers, but remain in its lower layers.
- Statistics conducted on skin cancer cases in the North Pole and South Pole, and other regions worldwide where the ozone layer is of great thickness indicate close results.
Given these logical arguments, we may say that the ozone hole is a natural phenomenon that is not cause for concern. However, we are not quite sure of this; there are several ongoing researches and studies to make sure the hole does not represent any danger to life.
References
nstarzone.com
theozonehole.com
freepik.com
**The original article was published in SCIplanet Magazine, Spring 2017 issue.