Since the invention of CFCs over 60 years ago, these chemicals have been found to be used in numerous products around the world. It was once considered a miracle invention where no harmful side effects were noted. The only problem is that scientific evidence has proven that these chemicals are a contributing factor to the ozone layer depletion that has been occurring since the invention of CFCs. The US has begun phasing out their production and the world has been rapidly scaling back their use, but the damage has already been done.
Although it was long suspected, the first confirmed sighting of a large hole in the ozone layer was reported over Antarctica in 1985.
Ozone Layer Depletion
Although it’s a hole in the ozone layer that we like to talk about, there have been decreases in stratospheric ozone over populated regions in the same time. Recent data shows that the planet may be recovering and that our efforts are working, but we still have a long way to go. By knowing the statistics about ozone layer depletion, we can keep working hard at restoring our planet so that it is available for future generations to enjoy.
- The ozone layer is a belt of naturally occurring ozone gas that sits 9.3 to 18.6 miles above the planet.
- It’s job is to serves as a shield from the harmful UVB radiation that is emitted by the sun.
- Ozone is constantly being formed and broken down in the stratosphere, sometimes as low as 10 kilometers from the surface.
- Extra levels of UVB cause reductions in the growth of phytoplankton, which in turn lowers the population levels of other animals.
- Researchers have noticed changes in the reproductive rates of many forms of sea life, including frogs and salamanders, when exposed to high levels of UVB.
- One atom of chlorine can destroy more than 100,000 ozone molecules.
- When the sun shines for long periods of the day in the Antarctic, chlorine reacts with the sun’s ultraviolet rays, destroying ozone on a massive scale: up to 65%.
- Ozone levels have dropped by about 20% in other regions of the world.
- 90% of the CFCs released into the atmosphere came from the Northern Hemisphere.
- Scientists believe that it will take at least another 50 years for atmospheric conditions to begin stabilizing at pre-CFC invention levels.
- The CFCs are so stable that only exposure to strong UV radiation breaks them down.
We have been doing a lot to save the ozone layer and the statistics prove it. CFCs have been banned since 1996 and the amount of chlorine that is in the atmosphere has been beginning to fall. This is good news, so catastrophic predictions no longer serve a purpose. What we need to keep doing is emphasize responsible management of our natural resources. We have seen changes over the last two decades that show how humanity can improve the planet or repair it when we all work together. That’s something that we need to keep doing right now so that the ozone layer can continue to improve. In order to keep that momentum going, we also need to empower ourselves with information about ozone layer depletion that we might not know about already.
What Are Some Facts You Might Not Know?
- Only 7% of the radiation that the sun emits is considered to be harmful.
- The concentration of ozone is usually only a few parts per million and even in the ozone layer it is only one part in 100,000.
- The loading of ozone destroying chemicals at the Antarctic surface has been dropping since its peak in 1994 and is now about 6% down from record highs.
- Despite improvements, the ozone hole in 2003 was one of the largest in history because of weather shifts.
- Global warming is linked to ozone layer depletion in 2 ways: it creates a cooler upper atmosphere and increases the amounts of methane and carbon dioxide that are present, creating the conditions for global ozone depletion.
- Some CFCs have an estimated shelf life in the atmosphere of 150 years.
One of the great debates that we have today is about natural variation. How much ozone layer depletion is a natural variation of what our planet does on a regular basis? How much of global warming is attributed to just a regular climate shift that has been seen in global patterns throughout history? You’ll often get very different answers based on individual perspectives. One side believes that many of the issues that we are seeing today are man-made. The other side believes that most of what is being seen is a natural phenomenon and nothing else. The truth is likely somewhere in the middle. Scientific evidence shows that we are responsible for ozone layer depletion at some level. Ozone levels reduce naturally because of the changing seasons and so there is some climate shift responsible too. Our job is to manage the man-made consequences so that the natural shifts and events don’t enhance them and create a bigger problem.
How Bad Has Ozone Layer Depletion Been Historically?
- In 1984, British Antarctic Survey scientists showed that ozone levels had dropped to 10% below normal January levels for Antarctica.
- Studies between 1974-1978 showed that the ozone layer would be depleted by 7% overall within 60 years if current trends were not stopped.
- Even though CFCs were invented in the 1920s, tracking data for them did not begin until 1978 with the launch of the Nimbus 7 satellite.
- October 1984 ozone levels were about 35% lower than the average for the 1960s.
- The ozone hole can be as big as 1.5 times larger than the United States.
- Since 1979, ozone levels have fallen about 5% per decade when averaged over the entire year over populated regions.
- The amount of decrease per decade in winter ozone protection over populated portions of the planet: 10%.
- Ozone levels reached their lowest levels in the 1990s and there have been corresponding decreases in all ozone levels in populated areas since 2002.
- Numerous experiments have shown that CFCs and other widely-used chemicals produce roughly 84% of the chlorine in the stratosphere.
- As the eruption of Mount Pinatubo proved in 1991, natural eruptions can have a dramatic negative effect on the man-made ozone layer depletion chemicals that are in the atmosphere.
We often think of ozone layer depletion as a modern problem, but it is something that started well before the 1970s. CFCs have been manufactured since the 1930s and were widely used for more than two decades for a wide variety of products. We believed that there was no harm in using them… Until data showed us otherwise. Thankfully we were able to respond in just four years to this potential problem instead of the 24 years where we paid no attention to it. The ozone layer depletion issue is still something that needs to be addressed, but thankfully things are starting to get a little better. Instead of tracking how fast the planet will die, we are starting to track how fast the planet can recover.
How Do We Know Things Are Getting Better?
- In the past decade, the ozone hole over Antarctica has stayed at its current size of about 26 million kilometers.
- Ozone concentrations in the lower stratosphere over Antarctica are predicted to increase by 5%–10% by 2020.
- The ozone layer may recover up to 25 years faster than previously predicted thanks to the concentrated efforts by many nations to fix the problem.
- The total mass of ozone in the atmosphere is about 3 billion metric tons.
- Exposure to ozone levels of greater than 80 parts per billion for 8 hours or longer is actually considered to be unhealthy.
The research proves that the ozone layer is recovering. It’s actually recovering faster than anyone anticipated that it would. This means that we are doing something right and shouldn’t be trying to rock the boat. Things are going so well, in fact, that we need to start looking at what the healthy levels of ozone should be so that we don’t actually create an unhealthy environment. Ozone on its own interacts negatively with life on this planet. We needed high up in the air. We don’t need it saturated so much that it comes down to the ground and exposes us to unhealthy levels.
What Has The Ozone Layer Depletion Caused?
- There are more skin cancers, sunburns, and premature aging of the skin occurring within human populations than ever before.
- A sustained 10% thinning of the ozone layer is expected to result in almost two million new cases of cataracts per year.
- Early findings suggest that too much UV radiation can suppress the human immune system.
- Several of the world’s major crop species are particularly vulnerable to increased UV, resulting in lower yields.
- In domestic animals, UV overexposure may cause eye and skin cancers.
- Wood, plastic, rubber, fabrics and many construction materials are degraded by UV radiation.
- A loss of biodiversity in our oceans, rivers and lakes could reduce fish yields for commercial and sport fisheries.
- Early results suggest that plant growth, especially in seedlings, is harmed by more intense UV radiation.
- At temperate latitudes, where most people live, ozone depletion is sufficient to produce a variety of documented human health problems, and crop damage.
- Without extensive ozone layer protections, UVB protection would require humans to either live underground, under several meters of water, or wear protective clothing over every inch of our body.
As you can see, there is a lot at stake when it comes to the subject of ozone layer depletion. Although a depleting ozone layer isn’t going to automatically cause instant death, it is going to cause major problems that may not be economically sustainable. It goes beyond the increases in skin cancers and cataracts that are being seen in people and animals today. The world is producing more calories than it has ever been able to produce before. It’s coming at a perfect time, because the human population is at its largest size in history. If UV radiation were to destroy even a small portion of our global food supply, we would all be in trouble.
What Happens If We Keep Up The Hard Work?
- It is believed that the 1987 Montreal Protocol that banned or phased out ozone-eating depleting chemicals would help to prevent up to 2 million new cases of skin cancer every year beginning in 2030.
- The ozone layer is on track for recovery to 1980 benchmark levels by mid-century.
- If current trends stay on target, a total healing of the ozone layer could occur within the next 50 years.
- There are no guarantees that the damages caused by a reduced ozone layer over the last 3 decades is reversible.
If you were in school in the 1990s, there’s a good chance that your science teacher talks about the horrors of ozone layer depletion. Those science teachers might just have helped to scare us all straight. Was a complete phaseout of the harmful chemicals and substances in the works, our ozone layer looks to be on a path where it can completely heal. Although the benchmarks that are set are from 1980 data, which is 50 years after CFCs were first started to be used, there is still a lot of hope. We just need to keep working hard on what we’re doing so that our planet has a chance to continue supporting life in the way that we know it.