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Comment by jacobolus | Hacker News Reader

Ozone depletion was a very serious problem, so in the late 80s there was an international agreement to ban CFCs, halons, and other ozone-depleting chemicals.

It is by no means fixed yet, but now ozone is heading back towards its previous levels, and should be recovered by around 2075. This is a great example of activism working to solve a serious global problem via public policy changes.

You can read all about it: https://en.wikipedia.org/wiki/Ozone_depletion

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Though the CFC and ozone story is inspiring in some ways, it has limitations. It's a very specific problem caused by very specific substances used in a very specific way, for which alternatives are easily found. There isn't a lot of complexity to the problem, relatively speaking.

Except, in the same time frame, we went from only the West having Ozone polluting Air Conditioning, to pretty much the whole World having those. In the same time frame, the rest of the world industrialized and are using ozone damaging chemicals on a massive scale. There's no way we actually reduced these chemicals in absolute numbers. Yet the ozone layer is still intact, and apparently its improved. Care to explain?

> the rest of the world industrialized and are using ozone damaging chemicals on a massive scale

I would like to know more about the rest of the world you mentioned, since the Montreal Protocol (https://en.m.wikipedia.org/wiki/Montreal_Protocol) has been ratified by all United Nations members and the European Union. Based on observed data, it also seems to have the expected positive effect.

They are just now starting to phase out the r22 refrigerant used in ACs with a new one r410, which it self will be phased out. So during the last two decades, the number of ACs used, in places like India and China, has grown exponentially. I've been to India. Window ACs hanging out of windows everywhere. And thats only one of the polluting chemicals. Impossible to measure how much is released in China during manufacturing.

Perhaps, I've died and this is all a dream. But I do believe the world did not end yet. Despite all the articles from blowhards, preaching doom through the last two decades.

r22 has a much lower ozone depletion potential than r11/r12, which were used as refrigerants before. AC use in developing countries is more a global warming issue than an ozone shield issue. A lot of replacements are highly potent greenhouse gases.

The ozone shield had a 4 percent loss since the 70s in average, much larger local losses aka "ozone holes". Fortunately not many people live at the north or south pole.

This sheds some light on what it took to get enough support to actually change regulations:

https://www.sciencehistory.org/distillations/podcast/whateve...

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