The ozone-hole comeback that was really one fluke year

Dark viral-explainer-style line chart titled “The ozone hole is coming back” plotting the Antarctic ozone hole’s yearly maximum area on a zero-based axis from 2019 to 2023, a gold line with a filled area beneath climbing from 16.4 to 26.0 million km² and annotated “16.4 → 26.0 million km², +58% in five years” — with no data shown before 2019 — Showing the misleading chart

The same series drawn in full from 1979 to 2025 on a light background, titled “The same data, two opposite headlines”: the yearly maximum ozone hole area climbs through the 1980s–90s to a record 29.9 in 2000, then drifts slowly and noisily down. 2019 is circled as an anomalous low of 16.4, and two shaded windows meeting at that trough show that cropping 2015→2019 yields −42% (“the hole is healing”) while cropping 2019→2023 yields +58% (“the crisis is back”); a note adds the recovery is real but slow (WMO projects a return to 1980 levels near 2066) and that 2024 and 2025 fell back to about 22 — Showing the misleading chart

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Start the Antarctic ozone-hole chart at 2019 — the smallest hole in three decades, courtesy of a freak weather event — and the next four years look like a 58% surge, a recovery thrown into reverse. Draw the whole record and 2019 is exposed as an outlier: the hole is drifting slowly, noisily downward, and 2022’s 26.5 million km² isn’t remotely near the 29.9 record of 2000.

NASA Ozone Watch, Goddard Space Flight Center — Antarctic ozone hole single-day maximum area, 1979–2025; annual figures corroborated by the NASA/NOAA yearly ozone updates, 2026Added July 14, 2026

01The claim

The ozone hole is coming back. After decades of healing, the Antarctic hole has grown 58% since 2019 — the Montreal Protocol’s signature success story is quietly going into reverse.

02The trick

Every point is NASA’s; the only editorial move is where the line begins. The chart starts in 2019 — and 2019 was the smallest ozone hole in more than three decades, shrunk to a 16.4-million-km² maximum by a rare sudden stratospheric warming, a burst of unusual polar weather that has nothing to do with the CFCs the hole is made of. Press start on that freak trough and any ordinary year that follows looks like an explosion: 16.4 → 26.0 is a real +58%, and it means almost nothing, because the baseline was a fluke. The series is noisy enough that the trick is easy — year-to-year swings are driven more by stratospheric temperature than by the slow chlorine decline underneath — so a four-year window measures weather, not trend. The crop even quits at 2023, tidily before 2024 (22.4) and 2025 (22.9) fell back. (This is our own demonstration, drawn in the house style of a “the ozone hole is back” explainer, from NASA Ozone Watch’s published maxima rather than from one specific post.)

03The fix

Show the whole record, 1979–2025, and 2019 snaps into place as the anomaly it was — the deepest notch on the chart, not a new floor. The real shape is a rise through the 1980s–90s, a plateau, and a slow, jagged decline; 2022’s 26.5 is smaller than 2000 (29.9), 2006 (29.6), 1998 (27.9) and 2015 (28.2), so “bigger than ever” is simply false. The same trough powers the opposite headline just as easily: crop 2015→2019 instead and the hole “shrank 42% — problem solved,” a victory lap that’s every bit as cherry-picked. The recovery underneath is genuine but glacial: chlorine peaked around 2000 and the WMO projects Antarctic ozone won’t return to 1980 levels until roughly 2066, while the large 2020–23 holes were amplified by Australian bushfire smoke (2020) and water vapour from the 2022 Hunga Tonga eruption — transient shoves, not a failure of the treaty. The tell is a start date with no reason but the story it tells, laid over a series jumpy enough that whoever picks the window picks the winner.