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Healing the Ozone Layer

Updated: Mar 17


You’ve most likely heard of ozone before, whether it was from your middle school earth science teacher, or from the reporter on the daily news. Most people know the basics; ozone is a gaseous elemental form of oxygen that plays a vital role in Earth’s atmosphere. But, have you ever truly learned about it aside from the bits and pieces you picked up while zoned out during science class?


The ozone layer is split into two parts: tropospheric and stratospheric ozone. Tropospheric ozone, formed by chemical reactions with industrial byproducts, is closer to the ground and can be harmful to human health. Stratospheric ozone, formed in the upper atmosphere, is further away from the ground and blocks harmful UV radiation from hitting Earth’s surface. In this blog, we will focus on the benefits of stratospheric ozone.


 

What is the Ozone Layer?


The ozone layer is actually just one layer of the stratosphere. The Earth’s atmosphere is composed of several layers; the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Most atmospheric ozone can be found in the stratosphere, which is about 9 to 18 miles above the Earth’s surface. Although ozone is only a trace gas in the atmosphere, it plays a pivotal role in the habitability of Earth. Ozone acts similarly to a sponge, absorbing UV radiation from the Sun just as a sponge absorbs water.


Ozone is a molecule made up of three oxygen atoms that is constantly formed and destroyed in the stratosphere. The concentration of ozone varies from place to place naturally due to sunspots, seasonal changes, and latitude differences. Scientists are able to predict many of these variations because they are periodic and natural reductions in ozone levels are always followed by recovery.


However, beginning in the 1970s, evidence showed that the ozone shield was undergoing depletion that could not be attributed to natural processes. Take a guess as to what caused that unnatural depletion. If you need a hint, it’s you! Humans are the number one contributor to ozone layer depletion, although the ozone layer is necessary to our survival.


The Importance of Ozone

As mentioned before, the ozone layer acts as a shield against harmful UV radiation from the Sun. UV light has the ability to penetrate human skin and cause adverse health effects. There are two major types of UV light: UVB and UVA. UVB light harms your skin by causing sunburns and sometimes skin cancers such as basal cell carcinoma and squamous cell carcinoma.


Most think that UVA light is harmless, as it is used in tanning beds and doesn’t cause burns. However, recent research reveals that UVA light is more harmful than UVB light, as it penetrates deeper beneath the skin and can cause melanoma.


The ozone layer absorbs about 98% of UV light. Without it, humans would suffer from severe burns and cancer to the point where the Earth would no longer be habitable. Interestingly, one reason we are hesitant to further explore life on Mars is because the planet does not have an ozone layer and therefore constant skin protection would be necessary for humans on Mars.


Depletion of the Ozone Layer


The ozone layer is getting thinner due to ozone depleting substances (ODS). Chlorofluorocarbons (CFCs) are an excellent example of these substances. Although the name may seem daunting, CFCs are just molecules that contain carbon, chlorine, and fluorine.


They are everywhere, but most commonly found in refrigerants and plastic products. They can also be found in everyday products like air conditioners, fire extinguishers, and aerosol sprays. CFCs are commonly used in these products because they are inexpensive, fire-resistant, and usually not poisonous.


However, the problem arises when CFCs reach the stratosphere. These chemicals create “ozone holes,” regions where ozone is extremely depleted. Ozone holes allow harmful UV rays to hit the Earth directly. Long-term exposure to UV radiation can cause skin cancer, eye diseases, and other health complications. To add the icing to the cake, many of the ODS, such as halons, methyl bromide, carbon tetrachloride, and methyl chloroform, also contribute to climate change!


Nuclear Testing


Scientists have found that ODS are not the only contributors to ozone layer depletion. Nuclear testing has been identified as a factor causing ozone layer depletion. Scientists are particularly concerned about the potential impact of a nuclear war which could devastate and destroy our ozone layer.


In the event of a global nuclear conflict, the resulting smoke from nuclear bombs could lead to the destruction of up to 75% of the ozone layer worldwide. Even a regional nuclear war would result in a peak ozone loss of 25% globally.


Healing the Ozone Layer


Montreal Protocol

Since the 1970s, when scientists first noticed the alarming rate of ozone layer depletion, large steps have been made toward its recovery. In 1987, the Montreal Protocol, a global agreement aimed at protecting the stratospheric ozone layer, was finalized. This agreement phased out the production and use of ozone-depleting chemicals, with a particular focus on chlorofluorocarbons (CFCs). As a result of these international efforts, 99% of ozone-depleting substances have been successfully eliminated.


By reducing the release of substances that harm the ozone layer, the Montreal Protocol played a crucial role in fixing the damage to the ozone layer. One of the most noticeable outcomes of these efforts has been the gradual reduction in the size of the ozone hole, particularly above Antarctica. In 2022, the ozone hole spanned an average area of 23.2 million square kilometers, a substantial decrease from its peak size of 27.5 million square kilometers recorded in 2006.


Next Steps

Despite the encouraging progress, the journey toward ozone layer recovery remains ongoing. Scientists and policymakers continue to monitor the ozone layer closely, implementing measures to mitigate further damage and promote its healing. Also, recent advancements in technology and scientific research have expanded the amount of options we have when it comes to helping the ozone layer heal.


Although we have made incredible progress, we must keep in mind that this is not the end. All of the work that we have put into healing the ozone layer could just as easily be reversed. We must continue our efforts to heal the ozone layer for the sake of our Earth and everything living on it.


 

Recap

The ozone layer, although thin, plays a pivotal role in absorbing harmful UV radiation from the Sun and protecting human life. Regardless of the simple fact that humans could not live on Earth without the ozone layer, we have slowly destroyed it over time by emitting CFCs into the atmosphere as industrial byproducts. These CFCs have slowly destroyed the ozone layer, causing “ozone holes” to appear which allow UV rays to reach Earth’s surface, causing cancer and other severe health issues in some cases.


However, not all is lost. The Montreal Protocol, created to reduce the production of ODS, was successful and the ozone layer has started to heal. But, it is still crucial to stay vigilant to make sure our progress is not reversed. If we continue on our current track, we will successfully preserve our ozone layer for generations to come!


Stay updated and active by following the Environmental Defense Initiative on Medium and our social media platforms!





Author: Maggie Yang


Editor: Emma Mazzotta


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