If you read my last post about Earth’s atmospheric layers, you may know how my curiosity about the current state of the ozone layer led me down the path to finding out more about Earth’s various atmospheric layers. I later realized (especially with the recent COP26 climate summit) that I’d never actually answered my initial question—just what is the current state of the ozone layer? And what would happen if it vanished completely?
The ozone layer is a secondary atmospheric layer. It protects the Earth from most of the ultraviolet rays coming from the Sun. Sunscreen lotion provides some protection from the Sun’s UV-A and UV-B rays, but what about its’ UV-C rays? If you’re not familiar with UV-C rays, that might be because 100% of the Sun’s UV-C light is absorbed by the ozone layer … which is fantastically great because UV-C rays are colossally harmful to all living things! The ozone layer also absorbs the majority of UV-A and UV-B rays—and it’s still a good idea to put on sunscreen if you’re going outside. … So, yeah. That’s why the Earth’s ozone layer is critically important for life on Earth to even exist at all.
Currently, ozone depleting substances are just beginning to decrease in the atmosphere. Most ozone depletion has been caused by chlorofluorocarbons (known as CFCs) and hydrochlorofluorocarbons (known as HCFCs), which are chemical combinations that were formerly used in refrigerants, aerosol propellants, and solvents. Even though production of them has been almost completely stopped for about 15 years, it takes an extremely long time for nature to get rid of these chemicals, which can hang in the atmosphere from 50 to 100 years. CFC levels peaked around the year 2000 and have been declining by about 4% per year since.
If the Earth did lose its’ ozone layer, things would get pretty bad for life on the planet. A NASA science team led by Paul Newman calculated what would happen with about two-thirds of the ozone layer gone, finding that skin cancer-causing radiation would surge. Middle latitude areas (those found within about 30 to 60 degrees north or south of the equator, such as Denver, Colorado, USA or Melbourne VIC, Australia) would get hit with ultraviolet radiation (UV) strong enough to give a person a sunburn in five minutes. Needless to say, DNA-mutating UV radiation would also skyrocket, and even if some plants, animals, and people suddenly gained superpowers, the majority of effects would probably be devastatingly harmful.
Thankfully, the world came together by 1987 (after discovering that CFCs punctured a “hole” through the ozone layer that opened up in winter over Antarctica) to recognize that ozone depleting substances needed to be banned. Diplomats, scientists, governments, industries, and others forged an agreement in what is known as the Montreal Protocol, an international treaty which took effect in January 1989 to regulate chemical pollutants destroying the ozone layer.
I have to admit, when I looked all of this up, I began wondering why, if the harmful chemicals that were tearing apart Earth’s ozone layer have long been banned, why is climate change and global warming such a dire issue today? So, of course, you know what I did…
Yup. I had to look it up.
And I found out that it’s more complicated than simply removing ozone-depleting chemicals from the atmosphere. That’s because there’s also substances known as greenhouse gases that are greatly harming Earth’s atmosphere. Basically, greenhouse gases were dubbed “greenhouse” because they produce an effect similar to what glass walls in a greenhouse do when they allow sunlight to shine inside and trap warmth within the greenhouse. In the same way, greenhouse gases let the sun’s light heat the Earth’s surface, but then trap that heat in the atmosphere rather than letting it escape out into outer space (like it would normally do when there are no greenhouse gases keeping it there).
It’s all really depressing, and I hate to end on a down note … so maybe consider talking to anyone you might know who could influence leaders to enact needed policy changes in carbon dioxide emissions. … And I’ll look more into greenhouse gases and share what I find in my next post.