rs79.vrx.palo-alto.ca.us

2010 NatGeo

hysteria

nasa

ravishankara1994

strahan2014

smallest

2010 NatGeo A recovering ozone layer could have a troubling side effect: boosting global warming "Ozone itself is a greenhouse gas. A thinner ozone layer not only reduced heat trapped over the region, it helped stir circumpolar winds, which in turn created sea spray that formed reflective, cooling clouds..." Hole in the ozone layer? Bad. Hole closing? Bad. Somehow the idea the patent ran out on Freon doesn't enter the conversation. Should we switch back ar DuPont's expense? I would, the reduced efficiency of HCFCs over CFCs is a waste of energy that causes more pollution than any gains from it. hysteria Until 1988 there was more hysteria about ozone than warming And what happened? It went away without a sound. Nobody cares anymore because it was never real. nasa Big Ozone Holes Headed For Extinction By 2040 "Since the Montreal Protocol agreement in 1987, emissions have been regulated and chemical levels have been declining. However, the ozone hole has still remained bigger than 8 million square miles since the early 1990s, with exact sizes varying from year to year. "The size of the ozone hole varies due to temperature"

ravishankara1994 Atmospheric Lifetime, Its Application and Its Determination : CFC-substitutes as a Case Study J. CHEM. SOC. FARADAY TRANS., 1994, 90(15), 2159-2169 FARADAY RESEARCH ARTICLE A. R. Ravishankara"? and Edward R. Lovejoy Aeronomy Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder CO 80303, USA "Lastly, the question is raised: Should atmospheric lifetime be used as an index of acceptability ? " HCFC's were promoted as a replacement for CFC's because the don't last as long. Who cares how long they last they're all going to react, they'll react long before they expire. That's like being given a poison that expires in 100 years. So what if it lasts that long that damage is done now, not 100 years after not reacting for that long. If chlorine is being pumped into the atmosphere from CFC's and it's not reacting for 100 years how is it depleting the ozone layer? It is of course, it's all reacting neatly instantly. "CFCs were hailed as the most stable and non-toxic compounds ever produced by mankind" "Measurements by Lovelock in the 1970s3 established the ubiquity of CFCs in the atmosphere. This pioneering work prompted Rowland and Molina to suggest that, because of their inertness, CFCs could transport chlorine to the stratosphere and promote ozone depletion. " This is the James Lovelock that recanted when it stopped warming. "The majority of species emitted by natural processes into the atmosphere have lifetimes of less than a few years. The hydrocarbons emitted from trees, for example, live for a few hours or possibly a few days. Methane, which has significant natural sources, has an atmospheric lifetime of about 10 years. CO, and N,O are exceptionally long-lived natural emissions which have lifetimes of nearly a century. The main sink for CO, is conversion into carbonates in the oceans while N,O is removed primarily by photolysis in the stratosphere. All the natural species are short-lived compared to some of the compounds produced by humans. The most stable gases emitted by humans appear to be the perfluoro compounds. These molecules, which are very potent greenhouse gases, have atmospheric lifetimes of thousands of years. As mentioned earlier, the time it takes to cleanse the atmosphere increases proportionately with the atmospheric lifetime. Therefore, even though there may be no currently identified harm to the atmosphere due to the emissions of a very long-lived species, one cannot be certain that they are benign. When CFCs were invented and released into the atmosphere, their deleterious effects were not known. Fortunately, CFCs are relatively short lived, compared to PFCs, and it will take only about a century for CFCs to be removed from the atmosphere once their emissions are curtailed. The release of any very long-lived species in the atmosphere should be viewed with the greatest concern. The PFC lifetimes, though long on historical timescales, are short compared to the evolutionary timescales. Hence, life on Earth may not be able to adopt to the changes these emissions may cause. Thus, it seems prudent to ask if the long-lived... " strahan2014 Inorganic chlorine variability in the Antarctic vortex and implications for ozone recovery S. E. Strahan, A. R. Douglass, P. A. Newman, S. D. Steenrod First published: 18 December 2014 DOI: 10.1002/2014JD022295 "The expected annual Cly change due to the Montreal Protocol is −20 ppt/yr, but the MLS-inferred Cly varies year-to-year from −200 to +150 ppt. Because of this large variability, attributing Antarctic ozone recovery to a statistically significant chlorine trend requires 10 years of chlorine decline. We examine the relationship between equivalent effective stratospheric chlorine (EESC) and ozone hole area. Temperature variations driven by dynamics are a primary contributor to area variability" "This relationship suggests that smaller ozone hole areas in recent cold years 2008 and 2011 are responding to decreased chlorine loading. Using ozone hole areas from 1979 to 2013, the projected EESC decline, and the inferred interannual Cly variability, we expect ozone hole areas greater than 20 million km2 will occur during very cold years until 2040. Cold years? "The expected annual Cly change due to the Montreal Protocol is −20 ppt/yr, but the MLS-inferred Cly varies year-to-year from −200 to +150 ppt. Because of this large variability, attributing Antarctic ozone recovery to a statistically significant chlorine trend requires 10 years of chlorine decline." We won't know until years is banning CFCs did any good. Some years it's way up some years it s way down. It did not agree with the models. The models, not nature, were wrong. "We examine the relationship between equivalent effective stratospheric chlorine (EESC) and ozone hole area. Temperature variations driven by dynamics are a primary contributor to area variability, but we find a clear linear relationship between EESC and area during years when Antarctic collar temperatures are 1σ or more below the mean. This relationship suggests that smaller ozone hole areas in recent cold years 2008 and 2011 are responding to decreased chlorine loading. Using ozone hole areas from 1979 to 2013, the projected EESC decline, and the inferred interannual Cly variability, we expect ozone hole areas greater than 20 million km2 will occur during very cold years until 2040. After that time, all ozone hole areas are likely to be below that size due to reduced EESC levels." It closes up in cold years. There are enough cold years it'll be closed soon. smallest 2019 Ozone Hole is the Smallest on Record Since Its Discovery Abnormal weather patterns in the upper atmosphere over Antarctica dramatically limited ozone depletion in September and October, resulting in the smallest ozone hole observed since 1982, NASA and NOAA scientists reported today.

ravishankara1994.pdf

strahan2014.pdf