tag:blogger.com,1999:blog-9487055.post3231326882899682177..comments2024-03-26T05:56:59.938+11:00Comments on THE PSYCHOLOGIST : JRhttp://www.blogger.com/profile/00829082699850674281noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-9487055.post-42704699954330985592016-10-15T02:50:16.247+11:002016-10-15T02:50:16.247+11:00There is a problem with the second sentence of thi... There is a problem with the second sentence of this post. The fact that the ozone hole was lrge last year does not mean that the CFC ban had no effect. First, CFC bans stopped production, but no country asked people to give up the CFC-containing products and equipment they already had. Thus, old refrigerators, foam insulation, and eve a few fire extinguishers and aerosol cans are still giving off CFCs today. Second, once they are released, CFC molecules can last decades to centuries in the atmosphere, so it will take decades for the ozone layer as a whole to get back to the levels it was at in the past. Third, the ozone hole is a different, but related, problem than the damage to the ozone layer in general. While the presence of some chlorine and bromine (from CFCs and similar chemicals) is necessary for the ozone hole to form, the size of the ozone hole in any one year depends more on the weather; when it's very cold more ice crystals form in the stratosphere, and the combination of the halogens and the ice crystals rapidly destroys the ozone nearby. That's why the holes form over the poles - that's where it's cold enough for these ice crystals to form. So now that CFC emissions are getting smaller every year instead of bigger, and as the CFCs already up there break down, eventually the ozone hole will stop forming each spring. But until then, there will still be some years where the hole is bigger and others when it is smaller.<br /><br /> October 15, 2016 at 2:34 AM<br />Robert Smallnoreply@blogger.comtag:blogger.com,1999:blog-9487055.post-32586246350349251872016-10-15T02:35:31.331+11:002016-10-15T02:35:31.331+11:00There is a problem with the second sentence of thi...There is a problem with the second sentence of this post. The fact that the ozone hole was lrge last year does not mean that the CFC ban had no effect. First, CFC bans stopped production, but no country asked people to give up the CFC-containing products and equipment they already had. Thus, old refrigerators, foam insulation, and eve a few fire extinguishers and aerosol cans are still giving off CFCs today. Second, once they are released, CFC molecules can last decades to centuries in the atmosphere, so it will take decades for the ozone layer as a whole to get back to the levels it was at in the past. Third, the ozone hole is a different, but related, problem than the damage to the ozone layer in general. While the presence of some chlorine and bromine (from CFCs and similar chemicals) is necessary for the ozone hole to form, the size of the ozone hole in any one year depends more on the weather; when it's very cold more ice crystals form in the stratosphere, and the combination of the halogens and the ice crystals rapidly destroys the ozone nearby. That's why the holes form over the poles - that's where it's cold enough for these ice crystals to form. So now that CFC emissions are getting smaller every year instead of bigger, and as the CFCs already up there break down, eventually the ozone hole will stop forming each spring. But until then, there will still be some years where the hole is bigger and others when it is smaller.Robert Smallnoreply@blogger.com