Central Idea

Satellite measurements conducted over Antarctica have unveiled a gigantic hole in the ozone layer.
Termed an “ozone-depleted area,” this region spans 26 million square kilometers (10 million square miles), approximately three times the size of Brazil.

Ozone Layer and Ozone Hole

Location	Stratosphere, approximately 10-30 km above Earth’s surface.
Composition	Composed of ozone (O3) molecules. Unit of measurement: Dobsob Unit (DU)
Function	Acts as a protective shield, absorbing and blocking a significant portion of harmful ultraviolet (UV) radiation from the sun.
Importance	Essential for protecting life on Earth by preventing excessive UV radiation, which can harm living organisms and the environment.
Ozone-depleting Substances	Threatened by ODS like chlorofluorocarbons (CFCs), halons, and other synthetic compounds commonly used in refrigeration, air conditioning, and aerosol propellants.
Montreal Protocol	An international treaty adopted in 1987 to phase out the production and consumption of ODS, resulting in significant recovery of the ozone layer.
Current Status	The ozone layer is in the process of recovery due to the success of the Montreal Protocol.
Environmental Impact	Protects ecosystems, prevents skin cancer, cataracts, and other health issues in humans.
Additional Facts	• The size of the ozone hole over Antarctica varies annually, opening in August and closing in November or December. • Special winds caused by the Earth’s rotation create a unique climate over Antarctica, preventing mixing with surrounding air. • When these winds subside, the hole closes.

Volcanic Eruption in Tonga: Scientists speculate that the extensive ozone hole this year may be linked to volcanic eruptions in Hunga Tonga, Tonga, between December 2022 and January 2023. These eruptions released water vapor and other elements into the stratosphere, impacting the ozone layer through chemical reactions.
Human-Induced Ozone Holes: In the 1970s, scientists discovered that human activities, primarily the use of chlorofluorocarbons (CFCs), led to significant ozone depletion. These chemicals released chlorine in the stratosphere, depleting the ozone layer.
Effective Mitigation: The Montreal Protocol, established in 1987, aimed to combat ozone depletion by phasing out ozone-depleting substances. This international agreement successfully reduced the size of ozone holes over the years.

Not a Primary Climate Change Cause: Ozone depletion is not a leading contributor to global climate change.
Impact of Rising Temperatures: However, rising global temperatures may influence ozone holes. Extreme fires, such as those in southeastern Australia in 2020 and 2021, injected smoke into the stratosphere, potentially contributing to ozone depletion.
Changing Seasons: Ozone holes can alter the progression of seasons, as they extend the duration of polar vortexes, thereby extending winter periods.