What is the ozone layer and how important is it?
The ozone layer is an area of the stratosphere that has a high concentration of ozone. This layer acts as a kind of "shield shield" for planet Earth as it absorbs approximately 98% of the high frequency ultraviolet radiation emitted by the sun.
Without this protective layer, human life on our planet would be virtually impossible to exist.
Ozone layer illustration
The hole in the ozone layer
In 1983, researchers made a discovery that caused much concern: the existence of a hole in the ozone layer in the stratosphere area over Antarctic territory. This hole was large, as it was approximately 10 million square kilometers.
Even in the 1980s, other smaller holes were discovered at various points in the stratosphere. Over time, these holes grew (especially over Antarctica), and in September 1992 they totaled 24.9 million square kilometers.
Evolution of the ozone hole in the 1980s and early 1990s
Ozone layer hole from 1979 to 2010 - Image courtesy NASA shows comparisons of the ozone layer on September 17, 1979, October 7, 1989, October 9, 2006, and October 1, 2010 (Photo: AP Photo / NASA)
The main cause of the hole in the ozone layer is the chemical reaction of CFCs (chlorofluorocarbons) with ozone. These CFCs are present mainly in aerosols, air conditioning, refrigerator gas, plastic foams and solvents. CFCs decompose in the stratosphere through ultraviolet rays, breaking ozone bonds and destroying its molecules.
The use of chlorofluorocarbon gas (CFC) is responsible for the hole in the ozone layer.
The existence of holes in the ozone layer is a major concern because radiation is not absorbed, reaching the ground and can cause skin cancer in people, since ultraviolet rays alter the DNA of cells.
Avoiding the sun when it is very strong, as well as using sunscreens, are the only ways to prevent and protect the skin.
The hole in the ozone layer also has to do with increasing global warming.
Ozone layer protection
In the 1990s, alarmed by the seriousness of the growing environmental problem, international bodies, governments, and environmental institutions sought to take practical steps to prevent the ozone hole from advancing. CFCs have been banned in several countries and their use has been phased out in others. Thus, a decrease in hole growth occurred. As of September 2011, the size was 26 million square kilometers. It is still a problem, but the pace of growth has slowed extremely.
Consumption of ozone-depleting content has also decreased considerably worldwide. In 1992, it was about 690 thousand tons, rising to approximately 45 thousand tons in 2011. With the intensification of the supervision and awareness of consumers, this number is expected to decrease even more.
According to scientists, the ozone layer is expected to normalize in four or five decades (around 2050), which is directly linked to the reduction in CFC use.
Ozone layer illustration
Curiosity: On September 16 is celebrated the International Day of Preservation of the Ozone Layer.