For once, some good climate news

A recovery of the ozone layer?

Posted 1/15/25

WASHINGTON, D.C. — The National Oceanic and Atmospheric Administration (NOAA) reports that the Antarctic ozone hole is smaller than it has been for many years. That’s still not small. At …

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For once, some good climate news

A recovery of the ozone layer?

Posted

WASHINGTON, D.C. — The National Oceanic and Atmospheric Administration (NOAA) reports that the Antarctic ozone hole is smaller than it has been for many years. That’s still not small. At its greatest extent in 2024, on September 28, it reached almost eight million square miles. The monthly average ozone-depleted region in the Antarctic this year was nearly three times the size of the contiguous U.S. 

Nevertheless, that’s an improvement, which scientists say is due to a combination of continuing declines in chlorofluorocarbons, an ozone-depleting chemical phased out by the Montreal Protocol, along with an unexpected infusion of ozone carried by air currents from north of the Antarctic.

“The 2024 Antarctic hole is smaller than ozone holes seen in the early 2000s,” said Paul Newman, leader of NASA’s ozone research team and chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, MD. “The gradual improvement we’ve seen in the past two decades shows that international efforts that curbed ozone-destroying chemicals are working.” 

In previous years, NOAA and NASA have reported the ozone hole ranking using a time period dating back to 1979, when scientists started tracking Antarctic ozone levels with satellite data. Using that longer record, which includes the years prior to recovery spurred by the Montreal Protocol, this year’s hole ranked 20th-smallest in area across 45 years of observations. 

The ozone-rich layer high in the atmosphere acts as a planetary sunscreen that helps shield us from harmful ultraviolet (UV) radiation from the sun. Areas with depleted ozone allow more UV radiation through, resulting in increased cases of skin cancer and cataracts. Excessive exposure to UV light can also reduce agricultural yields as well as damage aquatic plants and animals in vital ecosystems.

Scientists were alarmed in the 1970s at the prospect that chlorofluorocarbon (CFC) chemicals could eat away at atmospheric ozone. By the mid-1980s, the ozone layer had been depleted so much that a broad swath of the Antarctic stratosphere was essentially devoid of ozone by early October each year. Sources of damaging CFCs included coolants in refrigerators and air conditioners, as well as aerosols in hairspray, antiperspirant and spray paint. CFCs were also released in the manufacture of insulating foams and as components of industrial fire suppression systems.

The Montreal Protocol was signed in 1987 to phase out CFC-based products and processes. Countries worldwide agreed to replace the chemicals with more environmentally friendly alternatives by 2010. The release of CFC compounds has dramatically decreased due to the Montreal Protocol. But CFCs already in the air will take many decades to break down. As existing CFC levels gradually decline, ozone in the upper atmosphere will rebound globally, and ozone holes will shrink.

“For 2024, we can see that the ozone hole’s severity is below average compared to other years in the past three decades, but the ozone layer is still far from being fully healed,” said Stephen Montzka, senior scientist with NOAA’s Global Monitoring Laboratory.

Source: adapted from a newsletter from NOAA Communications. The mission of NOAA (noaa.gov) is to understand and predict our changing environment, from the deep sea to outer space, and to manage and conserve America’s coastal and marine resources.

NOAA, ozone layer, climate, change, recovery

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