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Comment by juliangamble | Hacker News Reader

> The lead author of the study, Susan Strahan, an atmospheric scientist belonging to NASA’s GSFC (Goddard Space Flight Center) in Greenbelt, Maryland explained that it can be clearly observed that the chlorine level near the ozone layer is coming down while reducing the amount of depletion in the ozone.

Quibble: Is it actually 'healing' if the depletion rate is decreasing? The hole in the ozone is still getting bigger. It's just getting bigger at a slower rate. (I realise that this is the title the article uses - but I believe it is incorrect).

(This is a particular issue in Australia - we have increased occurrence of skin cancer due to this.)

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I think that the article is possibly just poorly written.

According to Wikipedia, the ozone levels stabilised in the 90's, and started to recover in the 00's: https://en.wikipedia.org/wiki/File:Ozone_hole_recovery.jpg

I'm led to believe that the ozone layer depletes and regenerates in cycles, and what the article is highlighting is that the amount that is depleted in a depletion cycle is lower.

Ozone is created by extreme events during lightningstrikes and reduced by it reacting/beeing bound otherwise. So yes, there is a natural cycle, with slight variances around the norm.

I cant wait to see my bosses eyes- when i expand this theory of irresponsibility for everything upon bugs. There is a natural occurance rate of bugs and a natural error rate in software. To try and meddle with it- or to blame developers for it, is just plain wrong and nearly as insane as environmentalism.

Sometimes in the morning, you can smell it in the air- the distinct taste of lazy.

I disagree with this analogy. As software engineers become more experienced, they start avoiding patterns or obviously flawed software constructs which they recognize as potentially creating bugs in the future.

Things like marking fields of objects final/const, requiring immutability of objects, reduce bugs interior to objects. Immutable objects also reduce multithreading issues. That’s one pattern that can be used to reduce common bugs.

Nature doesn’t do this. For example: Southern California has a fire season (natural) followed by a wet season (natural) which tends to cause sever mudlides. These natural processes never learn from experience that large fires before the rain is more destructive (I know I’m stretching here and fires would be smaller if we didn’t put down the small ones initially).

My point is that humans, software engineers included, learn from past mistakes. Ideally we improve from those, not just throw our hands up and say bugs are a “natural” result of the software development process. Software will always have bugs, but ideally you as an engineer never make the same one twice (with the exception of off by one errors ;)

> Quibble: Is it actually 'healing' if the depletion rate is decreasing? The hole in the ozone is still getting bigger. It's just getting bigger at a slower rate.

Ozone is create in the upper atmosphere by UV light bombarding oxygen, among other mechanisms. The depletion rate is decreasing, but it's less than the creation rate, so the hole is healing. Even without chlorine, the ozone also decays back into O2 naturally.

I thought the same when reading the article. It consistently mentions that chlorine level is decreasing, reducing ozone depletion, which means ozone is indeed still declining, just at a slowing rate.

Since CFCs have a lifetime of 50-100 years, I guess it's reasonable to assume depletion will continue to slow over the next decades. Another question is whether it will increase again at some point. The article states:

> Scientists speculate that the accelerated healing of Antarctic ozone hole might occur somewhere from the year 2060 to 2080. However, a total healing of the same cannot be guaranteed.

By "accelerated healing" they probably mean re-accumulation of ozone, but I'm not sure.

I recommend everybody read the wikipedia article. Essentially the ozone is in a dynamic equilibrium - constantly degrading and constantly being created. When they say depletion, I believe they mean "total depletion to date" not "rate of depletion."

Per wikipedia, "Ozone levels stabilized by the mid-1990s and began to recover in the 2000s. Recovery is projected to continue over the next century, and the ozone hole is expected to reach pre-1980 levels by around 2075 .[4] The Montreal Protocol is considered the most successful international environmental agreement to date."

So I'm confused what new information this article is providing exactly.

https://en.wikipedia.org/wiki/Ozone_depletion

Ozone is not a relic, it's constantly generated in the stratosphere through exposure of O2 to UV light. If the rate of ozone depletion goes down that means it gives more of a chance for natural ozone (re)generation to catch up. Which has indeed been the case.

Additionally, the "ozone hole" is not a permanent phenomenon, it's a temporary event that occurs in the local spring and dissipates after several weeks (again because the race between ozone creation and depletion ends up being won by creation).

See, for example, ozone concentrations over Antarctica in September: https://ozonewatch.gsfc.nasa.gov/monthly/climatology_09_SH.h...

Versus December: https://ozonewatch.gsfc.nasa.gov/monthly/climatology_12_SH.h...

Indeed. Anecdotally, I can really FEEL the sun here compared to other places. I was on holiday on Hydra (one of the Greek islands), and outside for 8 hours on a clear sunny day, and got a light tan... I would've been sunburnt within an hour if I'd done the same at home.

I believe it's a little worse in New Zealand. When I go home, I get about 15 minutes in the sun before I start burning.

My father used to work with some Nigerian engineers who said that the sun stings a lot more in Australia and New Zealand than at home. I long thought that was the UV but I've since read that it's actually the infrared that causes the burning senstation.

Experience as a pale, unsupervised photochem grad student leads me to believe that short wave UV evokes a tingly feeling in the short term, longer wave UV evokes a more burny feeling and long ir evokes deep tissue heating (still useful in the winter, but just get a space heater)

As a New Zealander I can confirm. I can't spend more than 10 minutes in the direct sun without turning red as a tomato an my skin pealing a few days later.

Yep, SPF 85 cream is quite common in NZ and rare in Aus.

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