By the way Whistler, not to beat a dead wookie or anything, but the idea that once you’ve dropped below a certain level of atmospheric Cl, it quits having an effect, is analogous to a similar biological effect (there’s a name for this that escapes me).
Arsenic isn’t carcinogenic in drinking water for example, except at levels above 150 parts per billion. The explanation for this is that at lower levels, the human body can heal the damage faster than it is getting done. And in the case of arsenic, it’s a needed micro-nutrient.
If you smoked one cigarette (or cigar) a week, you would likely suffer no ill effects (other than stained teeth and bad breath that is).
Similarly, once Cl drops below its 1980 concentration, we are in the “no effect, planet can heal itself” range again. I figure the same thing applies for CO2 production: If we simply either stabilized or even just reduced the rate of growth of CO2 emissions, we’d go a long way to solving any potential problems with human caused global warming.
That is either good news or bad news, depending on whether we think it’s a good idea to be able to manipulate planetary climate. Having a thermostat that we can turn up to avert an ice age would be a Good Thing.™
Carrick - 10:05am on 05/07/2008
Final word is the reason the CFCs make it so high up is because they are chemically inert. It takes UV exposure to produce an environmental hazard. The actual chemical process responsible for the catalyzation of O3 is dirt simple, as far as I can see, the only thing that anybody has called in question is how efficiently the CFC drops its “bad-boy” Cl radical when exposed to UV radiation.
Carrick - 10:05am on 05/07/2008
What we’re missing here Carrick is the buildup in CFC’s from say 1960 to now.
Freon was banned as a aerosol propellent in 1978, did we not get a benefit from that?
The Whistler - 10:05am on 05/07/2008
Whistler, it’s back to the issue that you have to raise the atmospheric chlorine level above some “base level” before you see any effect from the added Cl, because as I mentioned before there are other sources and sinks contributing to the system. The 1980 level appears to represent that breakpoint. Likely there was a tiny effect before 1980, but it was buried in the noise floor.
Carrick - 10:05am on 05/07/2008
Whistler:
Freon was banned as a aerosol propellent in 1978, did we not get a benefit from that?
Just look at freon emissions as a function of time. They continued to grow until 1998, because aerosol propellent was just one of many sources for human CFC emissions.
Not very mysteriously, the peak in the size of the ozone hole occurred about that time too.
Carrick - 10:05am on 05/07/2008
Final word is the reason the CFCs make it so high up is because they are chemically inert.
(Bowing) Good enough. First time it’s been explained to me in a rational way.
FlyOnTheWall - 11:05am on 05/07/2008
Thanks for the info Carrick. I hadn’t thought the growth curve was quite as steep as that.
The Whistler - 11:05am on 05/07/2008
Fly: That’s how my chemistry professor put it, and that explanation stuck with me.
It’s one of those paradoxes: Take one of the most inert materials you can image, inject it into a complex system like the Earth, and get a large measurable effect from it.
Due to processes that I don’t fully understand, most of the Cl gets transported to the the polar regions; so there is almost no ozone depletion in tropical regions. Thus the ozone depletion at the poles is a pretty good measure of its effect.
This is one of those cases where there is a clear cost-benefit analysis too by the way. Damage to humans, livestock and crops far exceed the cost of going away from CFCs. And there really were companies trying to block the switch, like Dupont who had invested heavily into CFCs and were running an active program of disinformation.
The trouble is that the global warminists try to shoe-horn the success of the CFC effort into the global warming, and it is by no means a good fit.
The science is very complex, many of the mechanisms are either unknown aor at best poorly understood, the costs are likely prohibitive, where there are any net benefits is unclear, fossil fuel companies are by no means threatened by CO2 emission legislation (car companies, maybe), in fact Exxon-Mobile funds global warming advocates about 10 to 1 over denialists, and oo forth.
And in the case of the CFCS it was the scientists themselves who lead the charge. With global warming, it appears to be mostly socialists and environmentalists who are pushing this thing so hard, and for obvious ulterior motives. My opinion there.
Carrick - 11:05am on 05/07/2008
Wouldn’t the thousand or so atmospheric nuclear weapon detonations in the fifties and sixties, have caused an ozone depleation simular to Pinatubo?
papertiger - 04:05pm on 05/07/2008
well the energy released by a nuke very well could create more bOzone.
By the way Whistler, not to beat a dead wookie or anything, but the idea that once you’ve dropped below a certain level of atmospheric Cl, it quits having an effect, is analogous to a similar biological effect (there’s a name for this that escapes me).
Arsenic isn’t carcinogenic in drinking water for example, except at levels above 150 parts per billion. The explanation for this is that at lower levels, the human body can heal the damage faster than it is getting done. And in the case of arsenic, it’s a needed micro-nutrient.
If you smoked one cigarette (or cigar) a week, you would likely suffer no ill effects (other than stained teeth and bad breath that is).
Similarly, once Cl drops below its 1980 concentration, we are in the “no effect, planet can heal itself” range again. I figure the same thing applies for CO2 production: If we simply either stabilized or even just reduced the rate of growth of CO2 emissions, we’d go a long way to solving any potential problems with human caused global warming.
That is either good news or bad news, depending on whether we think it’s a good idea to be able to manipulate planetary climate. Having a thermostat that we can turn up to avert an ice age would be a Good Thing.™
Final word is the reason the CFCs make it so high up is because they are chemically inert. It takes UV exposure to produce an environmental hazard. The actual chemical process responsible for the catalyzation of O3 is dirt simple, as far as I can see, the only thing that anybody has called in question is how efficiently the CFC drops its “bad-boy” Cl radical when exposed to UV radiation.
What we’re missing here Carrick is the buildup in CFC’s from say 1960 to now.
Freon was banned as a aerosol propellent in 1978, did we not get a benefit from that?
Whistler, it’s back to the issue that you have to raise the atmospheric chlorine level above some “base level” before you see any effect from the added Cl, because as I mentioned before there are other sources and sinks contributing to the system. The 1980 level appears to represent that breakpoint. Likely there was a tiny effect before 1980, but it was buried in the noise floor.
Whistler:
Just look at freon emissions as a function of time. They continued to grow until 1998, because aerosol propellent was just one of many sources for human CFC emissions.
Not very mysteriously, the peak in the size of the ozone hole occurred about that time too.
(Bowing) Good enough. First time it’s been explained to me in a rational way.
Thanks for the info Carrick. I hadn’t thought the growth curve was quite as steep as that.
Fly: That’s how my chemistry professor put it, and that explanation stuck with me.
It’s one of those paradoxes: Take one of the most inert materials you can image, inject it into a complex system like the Earth, and get a large measurable effect from it.
Due to processes that I don’t fully understand, most of the Cl gets transported to the the polar regions; so there is almost no ozone depletion in tropical regions. Thus the ozone depletion at the poles is a pretty good measure of its effect.
This is one of those cases where there is a clear cost-benefit analysis too by the way. Damage to humans, livestock and crops far exceed the cost of going away from CFCs. And there really were companies trying to block the switch, like Dupont who had invested heavily into CFCs and were running an active program of disinformation.
The trouble is that the global warminists try to shoe-horn the success of the CFC effort into the global warming, and it is by no means a good fit.
The science is very complex, many of the mechanisms are either unknown aor at best poorly understood, the costs are likely prohibitive, where there are any net benefits is unclear, fossil fuel companies are by no means threatened by CO2 emission legislation (car companies, maybe), in fact Exxon-Mobile funds global warming advocates about 10 to 1 over denialists, and oo forth.
And in the case of the CFCS it was the scientists themselves who lead the charge. With global warming, it appears to be mostly socialists and environmentalists who are pushing this thing so hard, and for obvious ulterior motives. My opinion there.
Wouldn’t the thousand or so atmospheric nuclear weapon detonations in the fifties and sixties, have caused an ozone depleation simular to Pinatubo?
well the energy released by a nuke very well could create more bOzone.