2023 Antarctic Ozone Hole Reached its Maximum Size on September Ranking as the 12th Largest Single Day Hole on Record

Every year an ozone hole develops over the Antarctic region due to the existence of ozone-depleting substances in the stratosphere. The eruption of the Hunga Tonga Ha’apai volcano may have played an important role in this September record.

High above the Earth's surface, in the stratosphere, lies a fragile shield that protects all life on our planet from the harmful effects of the sun's ultraviolet (UV) rays—the ozone layer.

The ozone layer is primarily located in the lower portion of the stratosphere, approximately 10 to 30 kilometers above Earth's surface. Ozone (O3) molecules within this layer absorb and block a significant portion of the sun's harmful UV radiation, preventing it from reaching the Earth's surface.

This natural shield is crucial for life, as excessive exposure to UV rays can lead to skin cancer, cataracts, and other health problems in humans, as well as harm ecosystems and marine life.

Ozone Depletion

In the 1970s and 1980s, scientists noticed a significant decline in the ozone layer above Antarctica during the Southern Hemisphere's spring. This depletion became famously known as the ozone hole and scientists have tracked Antarctic ozone levels every year since 1979.

The primary culprits behind this phenomenon were human-made chemicals called chlorofluorocarbons (CFCs), which were commonly used in refrigerants, aerosol propellants, and foam-blowing agents.

When released into the atmosphere, these CFCs rise and eventually reach the stratosphere, where they are broken down by UV radiation. This process releases chlorine atoms, which then react with ozone molecules, leading to ozone depletion.

The 1987 Montreal Protocoloffsite link and subsequent amendments banned the production of CFCs and other ozone-destroying chemicals worldwide by 2010. The resulting reduction of emissions has led to a decline in ozone-destroying chemicals in the atmosphere and signs of stratospheric ozone recovery.

Scientific studies indicate that the ozone hole above Antarctica has started to shrink, a testament to the effectiveness of international collaboration and environmental policies.

What happened then this year?

The Role of Hunga-Tonga Eruption

On September 21, 2023, the Antarctic ozone hole reached its peak size, spanning 10 million square miles (26 million square kilometers). This measurement, conducted through satellite and balloon-based observations by NOAA and NASA, marks the 12th largest single day ozone hole recorded since 1979.

If Hunga Tonga hadn’t gone off, the ozone hole would likely be smaller this year, Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, said. “We know the eruption got into the Antarctic stratosphere, but we cannot yet quantify its full impact to the ozone hole.

The eruption of the Hunga Tonga-Hunga Ha’apai volcano in January 2022, which sent a massive plume of water vapor into the stratosphere, is believed to have played a role in the significant ozone depletion observed this year.

The presence of water vapor likely intensified ozone-depleting reactions over Antarctica early in the season.

Featured videos