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Comment by hammock | Hacker News Reader

>The collective annual warming effect of these five chemicals on the planet is equivalent to the emissions produced by a small country like Switzerland.

Why is warming effect what matters here? During the original CFC crisis, it was the hole in the ozone layer we were more worried about.

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Because it's non-negligible source of warming greenhouse gases that is completely avoidable - we have plenty of substitutes available to us with lower global warming potential. Releasing 1 kg of CFC-13 will trap the same amount of heat as 14,000 kg of CO2.

Project Drawdown lists managing refrigerants as one of the top 10 solutions to limit warming in both 1.5 and 2C scenarios.

https://www.drawdown.org/solutions/table-of-solutions

https://www.drawdown.org/solutions/refrigerant-management

Yes, but the point is the danger from the warming contribution is less than the danger from an ozone hole, so why focus on the warming? Unless the ozone depletion is below the recovery rate.

The combined emissions of CFC-13, CFC-112a, CFC-113a, CFC-114a and CFC-115 increased from 1.6 ± 0.2 to 4.2 ± 0.4 ODP-Gg yr-1 (CFC-11-equivalent ozone-depleting potential) between 2010 and 2020. The anticipated impact of these emissions on stratospheric ozone recovery is small. However, ongoing emissions of the five CFCs of focus may negate some of the benefits gained under the Montreal Protocol if they continue to rise. In addition, the climate impact of the emissions of these CFCs needs to be considered, as their 2020 emissions are equivalent to 47 ± 5 TgCO2.

https://www.nature.com/articles/s41561-023-01147-w

Thanks, that makes sense now.

Gg, Tg? Is that Giga-gram and Tera-gram? Why not kg, the SI standard unit for mass?

I think it is an SI unit: https://en.wikipedia.org/wiki/Orders_of_magnitude_(mass)

"Teragram" appeared in the original IPCC reports circa 1990, so this has been a thing for at least a gigasecond.

Adding an SI prefix to an SI unit is standard practice rather than adding a bunch of trailing zeros.

> Is that Giga-gram and Tera-gram?

Should be "gigagram" and "teragram," with no capitalization and no hyphen. See section 5.3 ("Unit Names") of the official SI Brochure.[0]

[0] https://www.bipm.org/documents/20126/41483022/SI-Brochure-9-...

The article suggests that it is currently below the recovery rate (but only just).

Both matter, though warming wasn't considered a big deal, the media was still coming away from warning about a coming ice age (i've never figured out what was going on there, as a kid I heard it more than once, but now few admit the scare existed). The ozone hole was a big deal.

Now that CFCs are banned the ozone layer is recovering. I'm guessing these emissions are not really enough to harm the ozone layer much (so long as they don't get worse!), but they add to greenhouse gases that are not in control.

>as a kid I heard it more than once, but now few admit the scare existed.

People very rarely admit to backing the wrong horse that. Nobody will tell you they sold AAPL and MSFT stock in the 90s. Nobody will tell you they believed the racist propaganda back in the 60s. Nobody will tell you they believed Iraq had WMDs in the 00s. Nobody will tell you that they believed the people who were saying Long Island would soon be under ice in the 70s.

Would love to hear what you think about the Ars Technica article linked in another reply to GP, and how it relates to what you and GP said.

I always figured it was a Y2K style "experts make narrowly scoped statements and journalists blow it out of proportion and make it look like the world is ending" type panic. The article doesn't really look into that side of things other than to say it happened.

They didn't address the popular media of the day, only what science was really saying.

Scroll down to "This journalist wrote a story, and you won’t believe what happened next"

There was like one story in a popular science magazine once that got a lot of play, and many people heard about it because it's a vivid story. That's about the extent of it.

Climate change deniers also keep it alive because enlarging it validates their distrust of scientists.

It was more than one story. PBS programs and other sources ran with it.

Notice that i'm careful to say it was the media, and not sound science.

No, the stories also made it into Newsweek and Time, which were pretty much the dominant credible news weeklies at the time, circulated to many millions of households. It's easy to look back now and say that was just sloppy work with little impact which has since been overblown, but I remember some academic authority figures in my young life taking the idea seriously a decade later as a result.

It was delivered with an imprimatur of authority from multiple sources and left an imprint for a long time.

I certainly advocated for action in Iraq in the early 2000s. I have a naive world view, informed I guess by a lot of 90s American media output, about America saving the world, Iraq was one of those opportunities.

I they hadn't totally botched it post invasion, maybe it would have worked too.

But let's see, tell 800k armed angry men they are out of a job and tell them to "go home, please don't steal any AK47s on your way out, mmmkay thanks goodbye go home and be a good boy now"

That was definitely one of the bad ones, but I think the root problem (which continues to this day) is that US foreign policy somehow manages to blend black-and-white moral histronics with an extremely shaky grasp of morality. The US can't work with moderates and pragmatists because anybody who's less than a pro-US liberal is beyond the pale, and it can't work with idealists because it spent the whole GWOT trumpeting about its torture program.

" though warming wasn't considered a big deal, the media was still coming away from warning about a coming ice age (i've never figured out what was going on there, as a kid I heard it more than once, but now few admit the scare existed)."

https://arstechnica.com/science/2016/06/that-70s-myth-did-cl...

> i've never figured out what was going on there

The media lying is what happened. Either because they don't know anything about any subject and misunderstood some very non-surprising papers or because somebody was paying them to lie so people wouldn't believe on global warming.

It's hard to say how much of what reason.

And nowadays people go scrutinize the scientific papers to find the bad ones... and there aren't any. Because there were never any, the entire thing waas invented elsewhere.

> And nowadays people go scrutinize the scientific papers ... and there aren't any.

That's provably not true, there are many bad scientific papers out there.

If its bad science in the first place, nothing downstream is ever going to be credible.

There was never much scientific discussion about Earth entering an ice age. So there aren't papers there, neither good nor bad.

There was something about fixed frequency cycles on our climate, that were the source of the thing. But those don't say anything not even similar to what the press run with.

That's because anthropologists are very particular about their methodology, and which papers get accepted for peer review.

We've known about precession, but since these cycles occur in the tens of thousands of years, and each cycle is usually offset by some cataclysmic event, little actual evidence remains.

They both matter, and the ozone hole has started to heal whereas global warming is getting much worse. 40 years ago, the CO2 level was also only 345ppm or so compared to 420ppm today and rising much more rapidly than in the 80s, so overall warming is becoming more acute.

People have become used to the thin ozone layer. In much of the world, you now can't stay outside all day without getting sunburn. There are not many reports of sunburn from 100 years ago.

I haven't managed to find any measurements or even estimates of what UV levels at ground level were before we started making CFC's - it seems we didn't think to measure it!

Feel sorry for all the animals and plants for whom suncream isn't an option...

> People have become used to the thin ozone layer. In much of the world, you now can't stay outside all day without getting sunburn. There are not many reports of sunburn from 100 years ago.

So are you saying we evolved skin melanin production from UV radiation for no reason whatsoever? People that live in the desert used to (and still do) cover themselves with clothing just because of fashion standards?

Sunburn has been a problem for our species ever since we shed most of our fur.

Romans were believed to have a 'pale white' skin. They lived in Rome, and while there are records of sunshades (Velarium), it doesn't seem they were common. For example, the colosseum, a place people might stay many hours, had only 30% coverage.

I don't think someone with similar skin would last long in Rome in the sun today...

> A strong distinction in skin color is frequently seen in the portrayal of men and women in Ancient Rome. Since women in Ancient Rome were traditionally expected to stay inside and out of the sun, they were usually quite pale; whereas men were expected to go outside and work in the sun, so they were usually deeply tanned

Those commoners sometimes wore hats (pileus)

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

There are also descriptions of treatments for sunburn.

There's no doubt that the ozone layer depletion increases the amount of UV light that we receive. Sometimes dramatically(very location dependent). But it's not like people could just toast in the sun all day without protection and not get burned.

People also had much lower life expectancies. I don't think it's useful to say that because the people in antiquity didn't have sun protection they were stronger or somehow immune to sunburns ... maybe they just died before living long enough for it to matter.

Or maybe they all died from cancers of all kinds, just not categorized as such, or died by murder / wars before cancer became an issue.

The vast majority of historically lower life expectancies is due to changes in death rates in the first few years. People who made it to adulthood weren't all keeling over at 35.

https://ourworldindata.org/grapher/life-expectancy-at-age-15...

Life expectancy at age 15 has gone up from 60 to 90

That’s still a massive increase

Modern people barely spend time outside compared to the Romans. No wonder we're getting sunburnt when we finally go out in peak summer. If you spend most of your time outside year round, you'll develop a natural deep tan which offers considerable protection from the sun.

Why risk melanoma for a little bit of "natural protection" when sun screen exists?

AFAIK the biggest risk of melanoma occurs from sunburn. I would guess a protective tan from regular sunlight is probably healthy overall (depending on how you get your tan: confounding benefits and risks for any activity would drown out signal?). Lifestyle risks trump melanoma risks.

Chronic sun exposure affects the skin differently than intermittent:https://www.researchgate.net/figure/Differential-dependence-...

If you stay indoors 95% of your time, then yes, by all means, use as much sunscreen as you can.

If you spend most of your time outside your whole life, your skin is already conditioned to deal with UV damage.

Otherwise we would have gone extinct due to skin cancer, aren't we?

I'm going to politely call bullhicky on this statement. Sunburns have existed for much longer than 100 years - in fact, the first modern/commercial sunscreen was invented almost 100 years ago. Cursory searching shows that Egyptians, Greeks, Romans, etc had different methods of attempting sunscreen.

Is the sun worse now than then? Maybe, probably. But it's borderline alarmist to just declare sunburns are a recent phenomena.

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