The Impact of Ozone Depletion by Chelsea Heredia
Cracks and holes in the ozone layer, first made apparent in the 1970s, initially demonstrated a threat most severe in Antarctica, but evidence reveals that this issue has an effect on the life and health of all of Earth’s organisms, including humans.
First of all, what is the ozone layer and what does it do for us? Ozone is a molecule that mostly resides in the stratosphere. Stratospheric ozone is like Earth’s “sunscreen”, serving as a shield to protect Earth’s surface from the sun’s harmful UV radiation. The ozone layer is extremely valuable since it absorbs over 90% of UV-A and UV-B radiation, which have enough energy to significantly damage to the living tissues and DNA of living organisms.
Starting in the late 1970s, though, atmospheric researchers and scientists found evidence that human activities were disrupting the ozone balance. Specifically, human production of chlorine-containing chemicals, such as chlorofluorocarbons (CFCs) contributes to ozone depletion and thinning. CFCs are a family of organic compounds that are used in refrigerators, air conditioners, as propellants in aerosol cans for deodorant and insect repellent and in Styrofoam products. As a result of these applications, CFCs may have released and escaped into the atmosphere through old, broken appliances. The depletion caused an area of several reduced ozone concentrations over most of Antarctica, which has come to be called to “ozone hole.”
Throughout our childhood, we all remember watching movies like Happy Feet paint an ideal, flawless image of Antarctica and its environment. However, Antarctica’s ecosystem is not necessarily as pretty a picture as it might seem, especially after significant impacts of ozone thinning and depletion. In marine life, phytoplankton and zooplankton are sensitive to UV radiation. This is a problem because plankton play crucial roles in complex aquatic ecological food webs. As plankton make up the base of the marine food chain, changes in their number and species composition will species higher up on the food chain. In Antarctica, UV radiation has already reduced the plankton populations by between 6-12%, affecting aquatic chains at a foundational level. Around the world, UV-B radiation has been found to cause damage to early developmental stages of fish, shrimp, crab, amphibians, and other marine animals and more increases in UV-B exposure could affect the whole marine food chain. According to a United Nations study, UV radiation increased about 4% from 1979 to 1992.
Even though it seems that ozone depletion may not affect our daily lives or that it was a bigger problem in the last century, humans are affected and do experience health consequences today. According to the United States Environmental Protection Agency (EPA), UV-B causes non-melanoma cancer and plays a major role in malignant melanoma development. Furthermore, it has been linked to the development of cataracts, a clouding of the eye’s lens, skin cancer, and a suppressed immune system.
Fortunately, ozone depletion has been recognized on a global level. 24 nations signed the Montreal Protocol on Substances That Deplete the Ozone Layer in 1987. This was a commitment to concrete steps toward reducing CFC production 50% by 2000, and by far, the most far-reaching environmental treaty to date. I personally think it is admirable how countries that export CFC products prioritized the protection of Earth’s atmosphere over their domestic economic self-interests in this case. These efforts contributed to an estimated fall of chlorine concentration to 1 parts per billion (ppb) by 2100.
What can humans do to ensure that estimated drop in chlorine concentrations will stay on track until the next century?
Can the production of future technologies and appliances contribute to more ozone depletion?
Can the production of future technologies and appliances contribute to more ozone depletion?
How do you think that the decrease in ozone depletion and thinning will impact Antarctica and the rest of the world?
References
Comments