AUSTIN (KXAN) — A new report has good news regarding our Earth’s ozone layer. The phasing out of harmful ozone-depleting chemicals has led to the partial recovery of our planet’s “ozone holes”, and is forecast to continue improving through the next few decades.

Latest ozone assessment

The most recent Scientific Assessment of Ozone Depletion, a collaborative report put together by NOAA, NASA, the World Meteorological Organization and the European Commission, attributes the improvements of our planet’s ozone layer to the Montreal Protocol. This protocol, adopted in September 1987, was and continues to be an international environmental agreement that regulates the production and use of nearly a hundred anthropogenic chemicals known to destroy ozone. These chemicals are referred to as ozone-depleting substances (ODS).

This protocol was followed by a 1990 amendment to the Clean Air Act that mandated NOAA and NASA to monitor ozone and ozone-depleting substances in the stratosphere

The 2016 Kigali Amendment took the Protocol one step further, requiring a phase-out of hydrofluorocarbons (HFCs), industrial chemicals used for cooling/refrigerating and known greenhouse gases.

The newly-released assessment states the protocol has largely resulted in the decline of two particular harmful chemicals, chlorine and bromine, that form ODCs.

The new study also highlights the reduction in global warming due to the elimination of ODCs, keeping the increase in global temperature away from the 3%-to-3.5% jump projected under an uncontrolled emission scenario.

Unfortunately, there is no evidence to suggest ozone recovery in the lower stratosphere

By the numbers

The 2022 assessment found total column ozone to return to 1980 levels by:

• 2066 in Antarctica
• 2045 in the Arctic
• 2040 for near-global average (60°N-60°S)

Seasonal variation

The Antarctic ozone hole “fills in” (lessens) some during Southern Hemisphere summer (DEC/JAN/FEB) when warmer weather and ozone-rich air from outside the region disrupts the reactions that create the ozone-depleting chemicals. The hole widens (expands) during Southern Hemisphere winter (JUN/JUL/AUG) when ODCs interact with extreme cold and strong winds, allowing the chemical reactions in the stratosphere to destroy ozone molecules at a faster rate.

The opposite is true in the Arctic. The ozone layer thins in the Northern Hemisphere winter (DEC/JAN/FEB) when colder temperatures and stronger winds are present, and expands during the summer.

To see a map of the current total ozone over the Arctic, click here.

To see a map of the current total ozone over Antarctica, click here.

The Antarctica ozone hole is bigger, measuring more depletion at its peak when compared to the Arctic due to different weather patterns and ununiform geography. The Antarctica ozone hole was also the first to be discovered (1985), while the Arctic ozone hole didn’t decline to a level low enough to be considered a “hole” until 2011 and is not a regular occurrence. Arctic ozone holes have been observed in 1997, 2011 and 2020.

Why does it matter?

The saying goes: “good up high, bad nearby.” Ozone higher up in the atmosphere, a layer we call ‘the stratosphere’, absorbs harmful UV rays put out by the sun. Ozone ‘nearby’ or at ground level, is a harmful chemical produced from a reaction between the sun, volatile organic compounds (VOCs) and nitrogen oxides (NOx) at the surface.

High levels of ground-level ozone can lead to respiratory and metabolic issues, and often trigger ‘Ozone Action Alerts’ as talked about by the First Warning Weather team.

Editor’s note: In what seems to be a constant stream of “doom and gloom” updates out of the science world, it’s nice to report some positive news regarding our planet, achieved through regulation, research and collaboration. –Meteorologist Kristen Currie