6 ms·

How is Ozone depletion going up after we banned cfcs?

colechristensen 3y ago
It’s not. The ozone issue is very much improved. But there are also plenty of things that affect ozone coverage so it doesn’t “get better” by a steady state percentage each year in a straight line.
- JumpCrisscross 3y ago
  > it doesn’t “get better” by a steady state percentage each year in a straight line It sort of does [1]. The Antarctic ozone layer should recover to 1980 levels within 50 years. As of 2022, "the overall concentration of ozone-depleting substances (ODSs) in the mid-latitude stratosphere had fallen just over 50 percent back to levels observed in 1980, before ozone depletion was significant" [2]. It should recover to 1980 levels by 2050 [3]. [1] https://scied.ucar.edu/learning-zone/atmosphere/ozone-layer https://scied.ucar.edu/learning-zone/atmosphere/ozone-layer [2] https://cires.colorado.edu/news/path-ozone-layer-recovery-passes-significant-milestone https://cires.colorado.edu/news/path-ozone-layer-recovery-pa... [3] https://gml.noaa.gov/odgi/ https://gml.noaa.gov/odgi/
  - graycat 3y ago
    Antarctic ozone depletion? A big problem? (1) The ozone molecule is O3 and is unstable so we can have the reaction 2O3 --> 3O2 where ozone returns to just ordinary oxygen. (2) Ozone can be generated by sunlight in the reaction 3O2 --> 2O3 (3) For ~6 months of each year, Antarctica gets nearly no sunlight. (4) For ~6 months of the rest of the year, Antarctica has sunlight for 24 hours a day. Soooo, for about half of each year Antarctica generates ozone and for the rest of the year "depletes" ozone. We expect this. (5) Ozone absorbs UV (ultraviolet) radiation from the sun. UV radiation can cause skin cancer. Apparently some laboratory experiments have confirmed that CFCs (Chlorofluorocarbons) speed up the depletion reaction. It might take careful, difficult science to say in kilograms how much ozone is depleted by how many kilograms of CFCs and how much in Watts and percentage UV results. I am unsure about such careful, difficult science. But I am fully sure about some people forming quasi religious, fanatical, extreme, unscientific movements based on claims that greedy, irresponsible, evil humans are destroying the delicate, pure, pristine, fragile planet we need for human life and, in the process, getting publicity from the media and money and power from political systems. Since the media likes to get eyeballs, ad revenue, and influence by writing stories about evil and disaster, we get stories about ozone depletion -- to me such stories have low credibility. No surprise since to me the media fails even common high school standards for term papers and has very low credibility -- worse than just "low credibility" since I have to conclude that commonly the media is trying to trick, fool, deceive, and lie to me, do me harm, etc. As we have seen in the US, the media stories can result in money and power from the political systems. The stories are old, go back at least to the claims of Chicken Little that the sky is falling and ... to the Mayans who killed people to pour their blood on a rock to keep the sun moving across the sky [1]. In short: There is ozone depletion over Antarctica? No surprise since for ~6 months of the year, Antarctica gets nearly no sunlight. What about ozone depletion over the US, e.g., likely the largest source of CFCs? Somehow the CFCs from the US generate legs and run ASAP down to Antarctica? And, no, I won't send all my money now or vote for some politician who wants to give money and power to protect ozone in Antarctica. [1] Susan Milbrath, 'Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars (The Linda Schele Series in Maya and Pre-Columbian Studies)', ISBN-13 978-0292752269, University of Texas Press, 2000.
    - bigbillheck 3y ago
      > In short: There is ozone depletion over Antarctica? No surprise since for ~6 months of the year, Antarctica gets nearly no sunlight. You cannot seriously think that this is something unaccounted for by the scientists, and it's barely a moment's work to find https://ozonewatch.gsfc.nasa.gov/meteorology/SH.html https://ozonewatch.gsfc.nasa.gov/meteorology/SH.html which says: > The ozone hole begins to grow in August and reaches its largest area in depth from the middle of September to early October. And also https://ozonewatch.gsfc.nasa.gov/meteorology/annual_data.html https://ozonewatch.gsfc.nasa.gov/meteorology/annual_data.htm... which has, among other data, "The mean ozone hole size for 07 September–13 October and the minimum of Southern Hemisphere mean ozone for 21 September–16 October for each year.". And furthermore https://earthobservatory.nasa.gov/world-of-change/Ozone https://earthobservatory.nasa.gov/world-of-change/Ozone with an animated plot of ozone concentrations. Please note the dates at each step, and how they correspond to the "Minimum Ozone / Minimum Daily" chart on the page I linked to in my previous paragraph. > I am unsure about such careful, difficult science. That's fine, and in general a pretty good policy. In this case seems to me that your reasoning is something like "this sounds complicated, my ideological enemies are endorsing the result, therefore it must be fundamentally flawed or irrelevant," That's a common enough stance, but in general I don't think it's particularly wise.
      - graycat 3y ago
        Okay, mostly we agree: When it is late summer in the northern hemisphere, e.g., August, it is late winter in the southern hemisphere and Antarctica with some months of low sunlight. Indeed, winter in Antarctica can mean some days of 24 hours with no sunlight. So, with no sunlight we don't get the reaction 3O2 --> 2O3 that makes ozone but do continue the reaction 2O3 --> 3O2 that sees unstable ozone convert back to oxygen. Similarly for low sunlight. Soooo, we get an "ozone hole". We agree -- no surprise. But in this case, in this Hacker News thread, the main issue was the effects of CFCs (Chlorofluorocarbons). As I recall, some laboratory studies showed that CFCs can speed up the reaction 2O3 --> 3O2 that destroys ozone. Maybe my memory is correct that there was a Nobel prize for that result. Sooo, okay, CFCs contribute to ozone holes. Then a question is, how much? How much do CFCs contribute to ozone holes? I.e., 1 kilogram of some CFC destroys how many additional kilograms of ozone per day causing how many additional Watts of UV (ultraviolet) light hitting the ground? And what is the increase in percent? Uh, and maybe what is the stochastic process of ozone concentration considering solar flairs, sun spots, the standard 11 year cycle of sun spots with or without CFCs? I remember ozone -- it has a distinctive odor. As a child I had an electric train, and sparks from its electric motor generated some ozone, enough to smell. But the ozone didn't last very long, e.g., was gone within a few minutes, certainly in less than an hour, of stopping the toy electric train. Uh, I just looked it up: Google search "half life of ozone in air" yielded "Under normal conditions, the half-life of ozone indoors is between 7 and 10 min and is determined primarily by surface removal and air exchange. ..." Point: Ozone is unstable and doesn't last very long. So, I can believe that with 24 hours a day of low or no sunlight over Antarctica, the ozone doesn't last very long, with or without CFCs. Uh, but with low sunlight, there is little UV to cause skin cancer, whatever the ozone concentration! So, to get concerned about CFCs and an ozone hole in August (late winter after some months of low or no sunlight) over Antarctica, I would want a good actual scientific answer to the question of how much? For the media, much of the media I don't like. I've had decades where I concluded their content is usually (a) without credibility and (b) deliberately deceptive. While I like entertainment, mostly what I want from the media is credible, relevant content. The deliberately deceptive parts I won't accept or excuse. Maybe you suspected that I am angry with much of the media -- that would be correct. I know something about writing credible content: I hold a Ph.D. in applied math from a world famous research university, have published peer reviewed papers of original research in applied math, statistics, and artificial intelligence, have taught at Indiana University, Ohio State University, Georgetown University, while at IBM's Research division gave talks at Stanford, Wharton, etc. The paper in applied math was on the Kuhn-Tucker conditions but also solved a problem stated but not solved in a paper by Arrow, Hurwicz, and Uzawa -- Arrow won his Nobel prize in economics long before and Hurwicz won his more recently and separately. An analysis is that the media wants to make money and to do this pursues some old techniques of journalism that involve fooling people, grabbing them emotionally by the heart, the gut, and below the belt. Such journalism is not nearly new: E.g., there is a movie from ~1941 Meet John Doe about a newspaper getting several months of twice as much circulation from a continuing but fake story about a John Doe committing suicide. Of course the reason there could be a movie about fake news is that the movie audience knew enough about journalism to accept that fake news was common. There was also yellow journalism. And tabloids. Etc. Of course, the technique of getting attention, power, and money by scaring people with threats from evil is much older even than fake, deceptive journalism, goes back 2000+ years -- apparently it's part of human nature and society, but we can try to fight it with good judgment, science, insisting on credible content, and rejecting fake content. So, people who want to create political movements and, thus, get money and power have natural colleagues in fake journalism. And, indeed and specifically, for CFCs, there was a movement with the media and politics: Due to the media touting threats to ozone, CFCs were actually outlawed. So, when I look at claims of threats of CFCs causing a worse ozone hole I see two possibilities: (1) As loudly claimed by some of journalism, CFCs make the ozone hole significantly worse and, thus, contribute significantly to skin cancer in the southern hemisphere. (2) We have no good scientific evidence that CFCs contribute significantly to either ozone holes or skin cancer, and the claims of threats are fake journalism trying to make money by grabbing people emotionally by the gut. Between (1) and (2), I select (2).
dheera 3y ago
Banning something in the US and the EU doesn't mean they are banned everywhere.
- JumpCrisscross 3y ago
  > Banning something in the US and the EU doesn't mean they are banned everywhere Banning something in the U.S. and EU, and then banning the import of products that use that banned something, has been pretty effective [1]. [1] https://gml.noaa.gov/odgi/odgi_fig2.png?2023 https://gml.noaa.gov/odgi/odgi_fig2.png?2023
Jackim 3y ago
I believe ozone depletion reduced between 2015 and now, so we're back to headed in the right direction. While much of the world adhered to the CFC ban, China had a brief resurgence of usage that created a temporary increase in depletion.
ceejayoz 3y ago
The page says "pressure is increasing on all boundary processes except ozone depletion".

It’s not. The ozone issue is very much improved. But there are also plenty of things that affect ozone coverage so it doesn’t “get better” by a steady state percentage each year in a straight line.

JumpCrisscross 3y ago
> it doesn’t “get better” by a steady state percentage each year in a straight line It sort of does [1]. The Antarctic ozone layer should recover to 1980 levels within 50 years. As of 2022, "the overall concentration of ozone-depleting substances (ODSs) in the mid-latitude stratosphere had fallen just over 50 percent back to levels observed in 1980, before ozone depletion was significant" [2]. It should recover to 1980 levels by 2050 [3]. [1] https://scied.ucar.edu/learning-zone/atmosphere/ozone-layer https://scied.ucar.edu/learning-zone/atmosphere/ozone-layer [2] https://cires.colorado.edu/news/path-ozone-layer-recovery-passes-significant-milestone https://cires.colorado.edu/news/path-ozone-layer-recovery-pa... [3] https://gml.noaa.gov/odgi/ https://gml.noaa.gov/odgi/
- graycat 3y ago
  Antarctic ozone depletion? A big problem? (1) The ozone molecule is O3 and is unstable so we can have the reaction 2O3 --> 3O2 where ozone returns to just ordinary oxygen. (2) Ozone can be generated by sunlight in the reaction 3O2 --> 2O3 (3) For ~6 months of each year, Antarctica gets nearly no sunlight. (4) For ~6 months of the rest of the year, Antarctica has sunlight for 24 hours a day. Soooo, for about half of each year Antarctica generates ozone and for the rest of the year "depletes" ozone. We expect this. (5) Ozone absorbs UV (ultraviolet) radiation from the sun. UV radiation can cause skin cancer. Apparently some laboratory experiments have confirmed that CFCs (Chlorofluorocarbons) speed up the depletion reaction. It might take careful, difficult science to say in kilograms how much ozone is depleted by how many kilograms of CFCs and how much in Watts and percentage UV results. I am unsure about such careful, difficult science. But I am fully sure about some people forming quasi religious, fanatical, extreme, unscientific movements based on claims that greedy, irresponsible, evil humans are destroying the delicate, pure, pristine, fragile planet we need for human life and, in the process, getting publicity from the media and money and power from political systems. Since the media likes to get eyeballs, ad revenue, and influence by writing stories about evil and disaster, we get stories about ozone depletion -- to me such stories have low credibility. No surprise since to me the media fails even common high school standards for term papers and has very low credibility -- worse than just "low credibility" since I have to conclude that commonly the media is trying to trick, fool, deceive, and lie to me, do me harm, etc. As we have seen in the US, the media stories can result in money and power from the political systems. The stories are old, go back at least to the claims of Chicken Little that the sky is falling and ... to the Mayans who killed people to pour their blood on a rock to keep the sun moving across the sky [1]. In short: There is ozone depletion over Antarctica? No surprise since for ~6 months of the year, Antarctica gets nearly no sunlight. What about ozone depletion over the US, e.g., likely the largest source of CFCs? Somehow the CFCs from the US generate legs and run ASAP down to Antarctica? And, no, I won't send all my money now or vote for some politician who wants to give money and power to protect ozone in Antarctica. [1] Susan Milbrath, 'Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars (The Linda Schele Series in Maya and Pre-Columbian Studies)', ISBN-13 978-0292752269, University of Texas Press, 2000.
  - bigbillheck 3y ago
    > In short: There is ozone depletion over Antarctica? No surprise since for ~6 months of the year, Antarctica gets nearly no sunlight. You cannot seriously think that this is something unaccounted for by the scientists, and it's barely a moment's work to find https://ozonewatch.gsfc.nasa.gov/meteorology/SH.html https://ozonewatch.gsfc.nasa.gov/meteorology/SH.html which says: > The ozone hole begins to grow in August and reaches its largest area in depth from the middle of September to early October. And also https://ozonewatch.gsfc.nasa.gov/meteorology/annual_data.html https://ozonewatch.gsfc.nasa.gov/meteorology/annual_data.htm... which has, among other data, "The mean ozone hole size for 07 September–13 October and the minimum of Southern Hemisphere mean ozone for 21 September–16 October for each year.". And furthermore https://earthobservatory.nasa.gov/world-of-change/Ozone https://earthobservatory.nasa.gov/world-of-change/Ozone with an animated plot of ozone concentrations. Please note the dates at each step, and how they correspond to the "Minimum Ozone / Minimum Daily" chart on the page I linked to in my previous paragraph. > I am unsure about such careful, difficult science. That's fine, and in general a pretty good policy. In this case seems to me that your reasoning is something like "this sounds complicated, my ideological enemies are endorsing the result, therefore it must be fundamentally flawed or irrelevant," That's a common enough stance, but in general I don't think it's particularly wise.
    - graycat 3y ago
      Okay, mostly we agree: When it is late summer in the northern hemisphere, e.g., August, it is late winter in the southern hemisphere and Antarctica with some months of low sunlight. Indeed, winter in Antarctica can mean some days of 24 hours with no sunlight. So, with no sunlight we don't get the reaction 3O2 --> 2O3 that makes ozone but do continue the reaction 2O3 --> 3O2 that sees unstable ozone convert back to oxygen. Similarly for low sunlight. Soooo, we get an "ozone hole". We agree -- no surprise. But in this case, in this Hacker News thread, the main issue was the effects of CFCs (Chlorofluorocarbons). As I recall, some laboratory studies showed that CFCs can speed up the reaction 2O3 --> 3O2 that destroys ozone. Maybe my memory is correct that there was a Nobel prize for that result. Sooo, okay, CFCs contribute to ozone holes. Then a question is, how much? How much do CFCs contribute to ozone holes? I.e., 1 kilogram of some CFC destroys how many additional kilograms of ozone per day causing how many additional Watts of UV (ultraviolet) light hitting the ground? And what is the increase in percent? Uh, and maybe what is the stochastic process of ozone concentration considering solar flairs, sun spots, the standard 11 year cycle of sun spots with or without CFCs? I remember ozone -- it has a distinctive odor. As a child I had an electric train, and sparks from its electric motor generated some ozone, enough to smell. But the ozone didn't last very long, e.g., was gone within a few minutes, certainly in less than an hour, of stopping the toy electric train. Uh, I just looked it up: Google search "half life of ozone in air" yielded "Under normal conditions, the half-life of ozone indoors is between 7 and 10 min and is determined primarily by surface removal and air exchange. ..." Point: Ozone is unstable and doesn't last very long. So, I can believe that with 24 hours a day of low or no sunlight over Antarctica, the ozone doesn't last very long, with or without CFCs. Uh, but with low sunlight, there is little UV to cause skin cancer, whatever the ozone concentration! So, to get concerned about CFCs and an ozone hole in August (late winter after some months of low or no sunlight) over Antarctica, I would want a good actual scientific answer to the question of how much? For the media, much of the media I don't like. I've had decades where I concluded their content is usually (a) without credibility and (b) deliberately deceptive. While I like entertainment, mostly what I want from the media is credible, relevant content. The deliberately deceptive parts I won't accept or excuse. Maybe you suspected that I am angry with much of the media -- that would be correct. I know something about writing credible content: I hold a Ph.D. in applied math from a world famous research university, have published peer reviewed papers of original research in applied math, statistics, and artificial intelligence, have taught at Indiana University, Ohio State University, Georgetown University, while at IBM's Research division gave talks at Stanford, Wharton, etc. The paper in applied math was on the Kuhn-Tucker conditions but also solved a problem stated but not solved in a paper by Arrow, Hurwicz, and Uzawa -- Arrow won his Nobel prize in economics long before and Hurwicz won his more recently and separately. An analysis is that the media wants to make money and to do this pursues some old techniques of journalism that involve fooling people, grabbing them emotionally by the heart, the gut, and below the belt. Such journalism is not nearly new: E.g., there is a movie from ~1941 Meet John Doe about a newspaper getting several months of twice as much circulation from a continuing but fake story about a John Doe committing suicide. Of course the reason there could be a movie about fake news is that the movie audience knew enough about journalism to accept that fake news was common. There was also yellow journalism. And tabloids. Etc. Of course, the technique of getting attention, power, and money by scaring people with threats from evil is much older even than fake, deceptive journalism, goes back 2000+ years -- apparently it's part of human nature and society, but we can try to fight it with good judgment, science, insisting on credible content, and rejecting fake content. So, people who want to create political movements and, thus, get money and power have natural colleagues in fake journalism. And, indeed and specifically, for CFCs, there was a movement with the media and politics: Due to the media touting threats to ozone, CFCs were actually outlawed. So, when I look at claims of threats of CFCs causing a worse ozone hole I see two possibilities: (1) As loudly claimed by some of journalism, CFCs make the ozone hole significantly worse and, thus, contribute significantly to skin cancer in the southern hemisphere. (2) We have no good scientific evidence that CFCs contribute significantly to either ozone holes or skin cancer, and the claims of threats are fake journalism trying to make money by grabbing people emotionally by the gut. Between (1) and (2), I select (2).

dheera 3y ago

Banning something in the US and the EU doesn't mean they are banned everywhere.

JumpCrisscross 3y ago
> Banning something in the US and the EU doesn't mean they are banned everywhere Banning something in the U.S. and EU, and then banning the import of products that use that banned something, has been pretty effective [1]. [1] https://gml.noaa.gov/odgi/odgi_fig2.png?2023 https://gml.noaa.gov/odgi/odgi_fig2.png?2023

Jackim 3y ago

I believe ozone depletion reduced between 2015 and now, so we're back to headed in the right direction. While much of the world adhered to the CFC ban, China had a brief resurgence of usage that created a temporary increase in depletion.

ceejayoz 3y ago

The page says "pressure is increasing on all boundary processes except ozone depletion".