The antarctic ozone hole is a case that demonstrates both humanity's ability to affect the atmosphere and humanity's ability to fix the damage we've done. The ozone hole began shrinking when we reduced CFC outputs by over 99%.
[quote]NASA began measuring Earth’s stratospheric ozone layer by satellite in 1979. By the time the Montreal Protocol went into effect in 1989, ozone concentrations (in Dobson units) had declined significantly over the Antarctic, enlarging the ozone hole. [/quote]
The American Chemical Society says: [quote] [b]Chlorofluorocarbons and Ozone Depletion[/b] A National Historic Chemical Landmark . . . “When we realized there was a very effective chain reaction, that changed the CFC investigation from an interesting scientific problem to one that had major environmental consequences,” Rowland told Chemical & Engineering News in an extensive interview in 2007. “You don’t often get many chills down your back when you look at scientific results,” he added, but that had been one of those moments.[/quote] https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/cfcs-ozone.html
