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Gases don't go to one place; they go everywhere including that place. Attention to the ozone problem is what leads the discussion in a direction of asking or ex

Gases don't go to one place; they go everywhere including that place. Attention to the ozone problem is what leads the discussion in a direction of asking or explaining "how CFCs got to the poles." Nobody asks how CFCs get to, I dunno, 15 miles above Scranton. But the lack of asking does not at all imply that there are no CFCs above Scranton. There is extra attention paid to the poles because an ozone hole appears there. In your spray-can story, the scent doesn't just go from the corner to your nose and concentrate there, it diffuses throughout the room. But its effect is noticed at the location of your nose and talked about because there's a human paying attention to smells at that spot. If you asked "How did the smell get to my nose?" you would get the answer, "It traveled there from the corner of the room." Which is correct, but not the whole picture. The question itself is biased to focus on your nose and exclude the rest of the room.

RobertRoberts 8y ago
>...it diffuses throughout the room... That was the lesson I was taught yes. But consider how much scent would have to be released to smell that same smell for 70 years, across the whole planet. I've read some articles on this linked here, and I see that there are many claims about what is happening, but in one PDF linked above this statement was made. >The role of PSC particles in converting reactive chlorine gases to ClO was not understood until after the discovery of the Antarctic ozone hole in 1985. Our understanding of the chemical role of PSC particles developed from laboratory studies of their surface reactivity, computer modeling studies of polar stratospheric chemistry, and measurements that directly sampled particles and reactive chlorine gases, such as ClO, in the polar stratosphere" I get that science has to extrapolate effects, because they simply can't sit in the sky and test the air all day long, it's not possible. But go look through history, how many times have scientists thought they understood something until later they changed their minds when more data was available. Note the source and timing of the ozone hole discovery: >* Joe Farman of the British Antarctic Survey discovered the Ozone Hole in 1984" https://en.wikipedia.org/wiki/Dobson_ozone_spectrophotometer https://en.wikipedia.org/wiki/Dobson_ozone_spectrophotometer Within 1 year of discovering the "ozone hole" they had an answer that hasn't changed to this day, based on computer modeling from the 80s. >*Total ozone was lower in these months [in 1984] compared with previous observations made as early as 1957." https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyquestions/Q10.pdf https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyq... We have a record of only 27 years of likely minimal data (from what I have read, no one was looking for a hole) where a difference was only discovered at the end of this data set, to which all the conclusions we have now are based. And everyone replying to me is saying this is absolutely settled science? No room for questioning this at all?
- rdiddly 8y ago
  Sure, question away, but if people are supposed to agree with you, you kind of need to supply some data or evidence. Skepticism is more than just saying "nothing is really known for sure" or "people have been wrong before." That argument won't overturn the prosecution's case in a court of law for example. What they test for in court, and in science, is reasonable doubt. Give them a reason to doubt, and absolutely they should doubt. People should reconsider their opinions when presented with contrary data. The problem is that you're not presenting any data. The people you're arguing against, have presented data. At their peak in 1989 before the Montreal Protocol went into effect (and a strangely coincidental multi-year observed trend began of rising ozone concentrations over Antarctica), CFCs were at a concentration of about 2 parts per billion. 70 years of humans releasing them worldwide could absolutely produce that, especially when you consider the long lifespan of those molecules. And they're a catalyst for the ozone breakdown reaction, not one of the reagents; so like most catalysts, they don't get used up, and like most catalysts, there is very little required in the first place. The classroom experiment might be leading you to overestimate how much CFC output would be required. Probably because the threshold concentration required for half of people to detect a smell -- let's say of ammonia, like after cleaning something with it, or in your cat's litter box, or near a place where people have been pissing -- has to be about 5 parts per million or 2,500 times as much as the peak CFC concentration in 1989. For ethyl alcohol, that cops seem able to smell like bloodhounds when they pull you over, the odor detection threshold is about twice that, or 5,000 times the peak CFC concentration. On the other hand you can smell hydrogen sulfide at only about 20% of the CFC amount, so hey. Maybe it's not a relevant experiment? Except to illustrate the concept of diffusion, which I already addressed satisfactorily, but now your concerns have shifted like a moving target to something else. How quickly an answer was found in 1985 has nothing to do with that answer's veracity. If a mosquito bites me in the ass, I figure it out right away; that doesn't mean there's no mosquito on my ass. How long an answer remains the accepted answer has nothing to do with its veracity either, which I think is what you're pointing out, but that also cuts both ways; its longevity doesn't falsify it, for example. If I'm right-handed for 40 years do I start to doubt my "handedness" because it didn't change often enough over the years? Because it's suspiciously consistent?? If anything the opposite happens, and it's the same in the science world: There are many professional, honest and earnest people out there making measurements and reporting the results. And if someone made a discovery that could overturn the prevailing ozone depletion theory, there is every incentive both professional and otherwise, to do so. That person only has to publish their data.

RobertRoberts 8y ago

>...it diffuses throughout the room... That was the lesson I was taught yes. But consider how much scent would have to be released to smell that same smell for 70 years, across the whole planet. I've read some articles on this linked here, and I see that there are many claims about what is happening, but in one PDF linked above this statement was made. >The role of PSC particles in converting reactive chlorine gases to ClO was not understood until after the discovery of the Antarctic ozone hole in 1985. Our understanding of the chemical role of PSC particles developed from laboratory studies of their surface reactivity, computer modeling studies of polar stratospheric chemistry, and measurements that directly sampled particles and reactive chlorine gases, such as ClO, in the polar stratosphere" I get that science has to extrapolate effects, because they simply can't sit in the sky and test the air all day long, it's not possible. But go look through history, how many times have scientists thought they understood something until later they changed their minds when more data was available. Note the source and timing of the ozone hole discovery: >* Joe Farman of the British Antarctic Survey discovered the Ozone Hole in 1984" https://en.wikipedia.org/wiki/Dobson_ozone_spectrophotometer https://en.wikipedia.org/wiki/Dobson_ozone_spectrophotometer Within 1 year of discovering the "ozone hole" they had an answer that hasn't changed to this day, based on computer modeling from the 80s. >*Total ozone was lower in these months [in 1984] compared with previous observations made as early as 1957." https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyquestions/Q10.pdf https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyq... We have a record of only 27 years of likely minimal data (from what I have read, no one was looking for a hole) where a difference was only discovered at the end of this data set, to which all the conclusions we have now are based. And everyone replying to me is saying this is absolutely settled science? No room for questioning this at all?

rdiddly 8y ago
Sure, question away, but if people are supposed to agree with you, you kind of need to supply some data or evidence. Skepticism is more than just saying "nothing is really known for sure" or "people have been wrong before." That argument won't overturn the prosecution's case in a court of law for example. What they test for in court, and in science, is reasonable doubt. Give them a reason to doubt, and absolutely they should doubt. People should reconsider their opinions when presented with contrary data. The problem is that you're not presenting any data. The people you're arguing against, have presented data. At their peak in 1989 before the Montreal Protocol went into effect (and a strangely coincidental multi-year observed trend began of rising ozone concentrations over Antarctica), CFCs were at a concentration of about 2 parts per billion. 70 years of humans releasing them worldwide could absolutely produce that, especially when you consider the long lifespan of those molecules. And they're a catalyst for the ozone breakdown reaction, not one of the reagents; so like most catalysts, they don't get used up, and like most catalysts, there is very little required in the first place. The classroom experiment might be leading you to overestimate how much CFC output would be required. Probably because the threshold concentration required for half of people to detect a smell -- let's say of ammonia, like after cleaning something with it, or in your cat's litter box, or near a place where people have been pissing -- has to be about 5 parts per million or 2,500 times as much as the peak CFC concentration in 1989. For ethyl alcohol, that cops seem able to smell like bloodhounds when they pull you over, the odor detection threshold is about twice that, or 5,000 times the peak CFC concentration. On the other hand you can smell hydrogen sulfide at only about 20% of the CFC amount, so hey. Maybe it's not a relevant experiment? Except to illustrate the concept of diffusion, which I already addressed satisfactorily, but now your concerns have shifted like a moving target to something else. How quickly an answer was found in 1985 has nothing to do with that answer's veracity. If a mosquito bites me in the ass, I figure it out right away; that doesn't mean there's no mosquito on my ass. How long an answer remains the accepted answer has nothing to do with its veracity either, which I think is what you're pointing out, but that also cuts both ways; its longevity doesn't falsify it, for example. If I'm right-handed for 40 years do I start to doubt my "handedness" because it didn't change often enough over the years? Because it's suspiciously consistent?? If anything the opposite happens, and it's the same in the science world: There are many professional, honest and earnest people out there making measurements and reporting the results. And if someone made a discovery that could overturn the prevailing ozone depletion theory, there is every incentive both professional and otherwise, to do so. That person only has to publish their data.