GREENBELT, Md. — While many climate change studies continue to paint a bleak picture for Earth’s future, NASA scientists say they have some good news heading into 2023 — the hole in the ozone layer is shrinking.
In a new report, a team from NASA’s Goddard Space Flight Center says the annual Antarctic ozone hole reached an average area of 8.9 million square miles between Sept. 7 and Oct. 13, 2022. While that may sound like a huge area, it’s slightly smaller than last year and continues an ongoing trend which shows that the hole is shrinking.
“Over time, steady progress is being made, and the hole is getting smaller,” says Paul Newman, chief scientist for Earth sciences at NASA’s Goddard Space Flight Center, in a media release. “We see some wavering as weather changes and other factors make the numbers wiggle slightly from day to day and week to week. But overall, we see it decreasing through the past two decades. The elimination of ozone-depleting substances through the Montreal Protocol is shrinking the hole.”
What is the ozone layer?
Due to human-produced compounds floating through the air, chemically active forms of chlorine and bromine attach to high-altitude polar clouds each southern winter. The reactive chlorine and bromine spark ozone-destroying reactions when the Sun rises at the end of the frozen continent’s winter.
Scientists with NASA and the National Oceanic and Atmospheric Administration (NOAA) are able to detect and measure this ozone hole using tools on board the Aura, Suomi NPP, and NOAA-20 satellites.
On Oct. 5, that trio of satellites registered a single-day maximum ozone hole of 10.2 million square miles. The team notes that single reading was slightly larger than last year’s measurement, even though the average continues to shrink.
When the polar sun rises, NOAA scientists are also able to take measurements using a Dobson Spectrophotometer. This tool records the total amount of ozone sitting between the planet surface and the edge of space, which scientists call the total column ozone value.
Worldwide, the average total column sits around 300 Dobson Units. When the team measured this at the South Pole on Oct. 3, they found the lowest total column ozone value of 101 Dobson Units. On that day, this means there was almost no ozone at all between eight and 13 miles above the surface. While this sounds concerning, it’s a very similar reading to last year, according to the scientists.
There had been concern that the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano may have further damaged the planet’s ozone layer, but the new report finds that the eruption did not have a direct impact.