The ozone layer is the area in the stratosphere where the concentration of ozone is higher than normal. This layer protects us from harmful ultraviolet radiation from the sun. However, the emission of certain chemicals known as chlorofluorocarbons has caused a hole in the ozone layerThis hole has been known for decades and is shrinking thanks to the Montreal Protocol. If you'd like more information on how it's stabilized, I invite you to read our article on the hole in the ozone layer.
In this article we are going to tell you everything you need to know about the hole in the ozone layer.
Definition of the ozone layer
Let's first learn what the ozone layer is. It's a kind of protective layer located in the stratosphere. This layer acts as a filter for ultraviolet solar radiation, which is harmful to living beings. It serves as a shield against this ultraviolet radiation, ensuring life on Earth as we know it today.
Despite the fact that this layer is very important for survival, it seems that humans are still determined to destroy it. Chlorofluorocarbons They are chemical substances that through various reactions destroy the ozone present in the stratosphere. These are gases composed of fluorine, chlorine, and carbon. When this chemical reaches the stratosphere, it reacts photolytically with ultraviolet radiation from the sun. This causes the molecule to break down and release chlorine atoms. Chlorine reacts with the ozone present in the stratosphere, causing oxygen atoms to form and breaking down the ozone layer. Thus, the emission of these chemicals is continuously causing the destruction of the ozone layer.
Furthermore, it must be taken into account that these chemicals have a long useful life in the atmosphere. Thanks to the Montreal protocol, the emission of these chemicals was totally prohibited. However, to this day, the ozone layer is still damaged. The hole in the ozone layer is significantly worsening compared to previous decades. Let's take a closer look at this.
Hole in the ozone layer
Ozone is found in the stratosphere at altitudes between 15 and 30 kilometers. This layer is made up of ozone molecules, which are themselves composed of three oxygen atoms. The function of this layer is to absorb ultraviolet B radiation, serving as a filter to reduce damage.
Ozone layer destruction occurs when chemical reactions cause the destruction of stratospheric ozone. Incident solar radiation is filtered by the ozone layer, where ozone molecules are broken down by ultraviolet B radiation. When this happens, ozone molecules dissociate into oxygen and dioxide. This process is called photolysis. It refers to the breakdown of a molecule by the action of light.
The forms of dioxide and oxygen are not completely dissociated, but rejoin, forming ozone again. This step does not always happen and it is what causes holes in the ozone layer. The main causes for The reason why the ozone layer is destroyed at an accelerated rate is due to the emission of chlorofluorocarbons. Although we mentioned that incident sunlight destroys ozone, it does so in a neutral balance. That is, the amount of ozone broken down by photolysis is equal to or less than the amount of ozone capable of forming through the association of molecules.
This means that the main cause of the breakdown of the ozone layer is due to the emission of chlorofluorocarbons. The World Meteorological Organization affirms that the recovery of the ozone layer will take place around the year 2050 thanks to the prohibition of these products. Keep in mind that all of these are estimates since, even if these chemicals are discontinued, they remain in the atmosphere for decades.
Consequences of the hole in the ozone layer
It's worth noting that the ozone hole is located primarily over Antarctica. Although most of the gases harmful to the ozone layer have been emitted in developed countries, there is an atmospheric current that carries these gases toward Antarctica. In addition, we must add the time that these gases remain in the atmosphere and that they are capable of damaging ozone.
Thanks to the planet's general circulation, these gases have benefited from the low temperatures in the southern hemisphere and have largely broken down this ozone layer. The destruction of this layer is accentuated as temperatures drop. This causes the ozone concentration to decline more in winter, while it recovers in spring.
There are various consequences of the deterioration or destruction of the ozone layer. Let's analyze them depending on who is affected.
Consequences for human health
- Skin cancer: It is one of the best-known diseases related to exposure to ultraviolet B radiation. It is necessary to sunbathe with protection since the disease does not appear immediately, but rather over the years.
- Immune system affection: acting on the body reduces its ability to protect ourselves against infectious diseases.
- Vision disturbance: it can lead to cataracts and presbyopia more often.
- Respiratory problems: Some problems are asthma due to the increase in ozone in the lower layers of the atmosphere.
Consequences on terrestrial and marine animals
It negatively affects all terrestrial animals and has similar consequences for humans. As for marine fauna, this radiation reaches the surface, directly affecting phytoplankton in the oceans. These phytoplankton populations are reduced to such an extent that it affects the food chain.
Consequences on plants
The incidence of this more harmful ultraviolet radiation affects the development of plant species, causing their flowering and growth periods to vary. All of this results in a reduction in plant populations and yields.
I hope this information helps you learn more about the hole in the ozone layer.