Large ozone hole detected over Antarctica

13 Oct 2023 8 mins Download PDF

Large ozone hole detected over Antarctica

Why in the News?

Recent satellite measurements by European Space Agency Copernicus Sentinel-5P satellite as part of the EU’s environmental monitoring program over Antarctica have detected a giant hole in the ozone layer.

• The hole i.e., the “ozone-depleted area” was 26 million square kilometers (10 million square miles) in size, roughly three times the size of Brazil.
• The satellite measured trace gases in the atmosphere in order to monitor the ozone and climate.
• The hole in the ozone is not likely to increase warming on the surface of Antarctica and hence, not a concern for climate change.

Ozone holes grow and shrink every year:

1. The ozone layer is a trace gas in the stratosphere, one of the four layers of the Earth’s atmosphere.
2. It functions as a protective gas shield that absorbs ultraviolet radiation, protecting humans and ecosystems from dangerous amounts of UV. 
3. Most skin cancers are caused by exposure to high amounts of UV radiation, so the ozone prevents UV rays and helps reduce cancer rates.
4. The size of the ozone hole over Antarctica fluctuates each year, opening each year in August and closing again in November or December.
5. Ozone hole opens up because of the rotation of the Earth causing specials winds over the closed landmass of Antarctica. 
6. The winds create a mini climate, creating a shield over Antarctica preventing it from mixing with surrounding air and when the winds die down, the hole closes.
7. It an ozone depletion takes longer time to repair, it may be due to a longer, more drawn-out polar vortex, which can lead to a wintertime lasting that little bit longer.

What caused the giant ozone hole this year?

1. This year’s big ozone hole is believed to be due to the volcanic eruptions at Hunga Tongain Tonga during December 2022 and January 2023.
2. Under normal conditions, gas released from a volcanic eruption stays below the level of the stratosphere, but this eruption sent a lot of water vapor into the stratosphere.
3. The water had an impact on the ozone layer through chemical reactions and changed its heating rate.
4. The water vapor also contained other elements that can deplete ozone like bromine and iodine. 
5. There is less evidence that ozone hole is due to humans.

Human-caused ozone holes:

1. Though this year’s Antarctic ozone hole was likely due to a volcanic eruption, human activities were creating huge ozone holes in the 1970s.
2. Ground and satellite-based measurements detected the holes, which were caused by widespread use of chemicals called chlorofluorocarbons and propellants used as gases to propel the solutions inside that contains chlorine.
3. They get released high in the stratosphere and depletes the ozone.
4. The Montreal Protocol was created in 1987 to protect the ozone layer by phasing out the production of these harmful substances.
5. The protocol was effective as ozone holes got smaller in the decades after ozone-depleting gas emissions were controlled.

Is climate change reopening ozone holes?

1. Ozone depletion is not a principal cause of global climate change.
2. However, there are signs that rising global temperatures could be having an impact on ozone holes.
3. The main reason for the large ozone hole in 2020 was due to the wildfires in southeastern Australia that year.
4. There is evidence that ozone holes change the progression of the seasons.