Antarctic ozone hole may fully recover by 2066

Once a year, over the icy desolation of the Antarctic, an ominous hole forms in the ozone layer. However, the 2024 story has taken a rather hopeful turn as the annual ozone hole was smaller compared to previous years.

Scientists at NOAA and NASA project that, if we keep up the momentum, we could see a full recovery of the ozone layer by 2066.

Seventh-smallest ozone hole

The 2024 ozone hole, as observed during the peak of the depletion season from September 7 to October 13, held the historic rank of the seventh-smallest.

The Montreal Protocol, an environmental treaty that phased out ozone-destroying chemicals, was ratified in 1992 and has proven to be a significant achievement.

Over the years, the ozone-depleted region has been alarmingly large, with 2024’s size averaging nearly three times the size of continental United States.

The worst of the ozone hole was seen on September 28, when it swelled to 8.5 million square miles – only to later shrink.

Recovery of the ozone hole

The experts attribute this year’s improvement to two key drivers – the continued decline of chlorofluorocarbons (CFCs) after the Montreal Protocol and a serendipitous surge of ozone carried by air currents from north of the Antarctic.

Paul Newman, leader of NASA’s ozone research team and a chief scientist at NASA’s Goddard Space Flight Center, elaborated on the state of the ozone hole.

“The 2024 Antarctic hole is smaller than ozone holes seen in the early 2000s. The gradual improvement we’ve seen in the past two decades shows that international efforts that curbed ozone-destroying chemicals are working,” said Newman.

Our shield against solar rays

Existing way up in Earth’s atmosphere, an ozone-rich layer serves as a planetary parasol, safeguarding us from the sun’s harmful ultraviolet (UV) rays.

When the ozone layer thins out, more UV radiation seeps through, leading to an increased risk of skin cancer, cataracts, and damage to aquatic ecosystems, as well as a reduction in agricultural yields.

Back in the 1970s, the scientific community was deeply concerned about CFCs – chemicals that were widely used in refrigerants, aerosols, insulating foams and even in some fire suppression systems.

These chemicals were gnawing away at the ozone layer. By the mid 1980s, the ozone layer over the Antarctic was drastically depleted.

It was then that the world came together to sign the Montreal Protocol in 1987, pledging to phase out CFCs and replace them with eco-friendly alternatives by 2010. Today, we are witnessing the success of this global commitment.

The road to ozone recovery

Stephen Montzka, a senior scientist with NOAA’s Global Monitoring Laboratory, urges caution.

“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 Montzka.

CFCs that are already in our atmosphere will take several decades to disintegrate. As their levels gradually drop, we can expect the ozone layer to bounce back, leading to the slow but certain reduction of ozone holes.

Monitoring our progress

NASA and NOAA scientists monitor the ozone hole yearly, noting that variations in atmospheric conditions, including transport of ozone-rich air from other regions, can influence its size and depth each year.

The scientists rely on a suite of systems to keep a close eye on the ozone layer. These include instruments on NASA’s Aura satellite and NOAA’s polar orbiting satellites.

NOAA also uses weather balloons, released from the South Pole Baseline Atmospheric Observatory, to measure ozone concentrations in Dobson units.

The 2024 concentration hit its lowest measurement at 109 Dobson units on October 5th.

“This is well below the 225 Dobson units that was typical of the ozone cover above the Antarctic in 1979,” said NOAA research chemist Bryan Johnson. “So, there’s still a long way to go before atmospheric ozone is back to the levels before the advent of widespread CFC pollution.”

Nonetheless, it’s crucial to remember that every small step toward recovery brings us closer to a healthier planet.

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