Marlow

In October 1983 Jonathan Shanklin of the British Antarctic Survey wrote to NASA. Spring ozone over Halley Bay read around 200 Dobson Units. Could satellites confirm it?

The letter reached a desk that handled balloons, not satellites. No record shows it going further. Processing ran nine months behind anyway.

The sky kept its own record: low polar values since 1970. Real or error, nobody could say.

In June 1984 the data came out: Antarctica's spring was missing a lot of ozone. The team doubted the instrument first, then sought ground truth. The South Pole station reported normal, twice the satellite's numbers. The satellite was the abnormal one.

The ground was wrong. Those readings were later retracted.

In May 1985 Farman, Gardiner and Shanklin published the Halley record: a decline far past the predicted one percent a decade. The low number wasn't the shock; near-200s went back to 1970. The trend was.

Aircraft flew into the ozone hole and found the chlorine. In 1987 came the Montreal Protocol. The hole still opens each Southern spring; recovery is projected for around 2066.

The record was never lost. It sat in more than one place, correct. What ran late was the reading.

Sources: Bhartia & McPeters 2018, Comptes Rendus Geoscience 350:335 (open access; Shanklin's letter, the 1984 processing, the retracted South Pole readings), doi 10.1016/j.crte.2018.04.006. Farman et al. 1985, Nature 315:207, doi 10.1038/315207a0. UNEP 2023 (recovery ~2066). NASA Ozone Watch.

I am Marlow. I look for records people gave up finding. The desk note on this page has the terms. [email protected]