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Global warming mitigation strategy would have adverse impact on ozone layerApril 25th, 2008 - 4:04 pm ICT by admin Washington, April 25 (ANI): A new research has warned that injecting sulfate particles into the stratosphere to offset global warming would have an adverse impact on Earths protective ozone layer. The ozone layer is critical for life on Earth because it blocks dangerous ultraviolet radiation from the Sun. Climate scientists, concerned that society is not taking sufficient action to prevent significant changes in climate, have studied various geoengineering proposals to cool the planet and mitigate the most severe impacts of global warming. One of the most-discussed ideas is to regularly inject large amounts of sun-blocking sulfate particles into the stratosphere. The goal would be to cool the climate, much as sulfur particles from large volcanic eruptions have cooling impacts. Now, a study, led by Simone Tilmes of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, warns that such an approach would delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic. Our research indicates that trying to artificially cool off the planet may be a perilous endeavor, said Tilmes. While climate change is a major threat, this solution could create severe problems for society, he added. The new study concluded that, over the next few decades, artificial injections of sulfates could destroy between one-fourth and three-fourths of the ozone layer above the Arctic. This could affect a large part of the Northern Hemisphere because of atmospheric circulation patterns. The sulfates would also delay the expected recovery of the ozone hole over the Antarctic by about 30 to 70 years, or until at least the last decade of the twentieth century, the authors have warned. In the Antarctic, the sulfate injections would not significantly reduce the thickness of the already depleted ozone layer. Instead, they would significantly delay the recovery of the ozone hole. The authors caution that the actual impacts on ozone could be somewhat different than estimated if atmospheric changes led to unusually warm or cold polar winters. They also warn that a geoengineering project could lead to even more severe ozone loss if a volcanic eruption took place at the same time. This study highlights another connection between global warming and ozone depletion, which had been thought of as separate problems but are now increasingly recognized to be coupled in subtle, yet profoundly important, ways, said co-author Ross Salawitch of the University of Maryland. According to co-author Rolf Muller of the Julich Research Center in Germany, Clearly much more research needs to be conducted to determine the full implications of geoengineering before we may discuss seriously the injection of sulfate aerosols into the stratosphere. Tags: adverse impact, antarctic ozone hole, atmospheric circulation patterns, boulder colorado, climate change, climate scientists, impacts of global warming, last decade, life on earth, mitigation strategy, national center for atmospheric research, ncar, northern hemisphere, ozone loss, protective ozone layer, stratosphere, study concluded that, sulfate particles, ultraviolet radiation, volcanic eruptions
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RUPA u zaštitnom ozonskom omotaču iznad Antarktike, koju mnogi smatraju najvećim svjetskim problemom na polju zaštite okoliša, proširila se brže nego prošlih godina i ponovno dosegla svoju rekordnu širinu od prije tri godine. Svjetska meteorološka organizacija objavila je da se rupa od 28 milijuna četvornih kilometara jako razlikuje od prošlogodišnje, kad je bila najmanja u posljednjih deset godina i podijeljena na dva dijela. U istoj organizaciji smatraju da se ne može predvidjeti hoće li se ozonska rupa nastaviti širiti sljedećih tjedana. Prošlogodišnje smanjivanje ozonske rupe navelo je neke dužnosnike na tvrdnju da su međunarodni napori poduzeti radi kontrole kemijskih zagađivača koji uništavaju ozon počeli davati rezultate. Ozonski omotač u višim dijelovima atmosfere sprječava prodor sunčevih ultraljubičastih zraka, a zdravstveni radnici upozoravaju da prekomjerno izlaganje tom zračenju izaziva pojavu raka kože i druge bolesti. Osim toga, ultraljubičasto zračenje uništava i biljke. Ozonska rupa ovisi o utjecaju sezonskih klimatskih promjena i zagađivanja, a obično je najveća od sredine do kraja rujna. Mnogi je smatraju pokazateljem općega stanja u ozonskome omotaču u ostalim dijelovima svijeta. Ozonski omotač uništavaju aerosoli i plinovi koji se rabe u rashladnim uređajima, a zabranjeni su u skladu s Montrealskim protokolom iz 1987. U Svjetskoj meteorološkoj organizaciji upozoravaju da bi za potpuni oporavak ozonskoga omotača bilo potrebno trajno provođenje međunarodnih sporazuma. Organizacije za zaštitu okoliša smatraju da bi se ti sporazumi morali odnositi i na nove kemijske sastojke koji se rabe u mnogim proizvodima, od onih za gašenje vatre do tekućina za čišćenje. Znanstvenici smatraju da se količina klorofluorougljici (CFC), koji uništavaju ozon, smanjuje u nižim slojevima atmosfere zbog manjeg ispuštanja tih plinova, ali se to ne događa i u višim slojevima atmosfere. Klimatski uvjeti iznad Antarktike, u "najvažnijem", gornjem sloju atmosfere, bili su prošle godine vrlo neobični, smatra Michel Profitt iz Svjetske meterološke organizacije, a to je ozonskome omotaču omogućilo postupni oporavak. Promjene veličine ozonske rupe mnogo više ovise o meteorološkim uvjetima nego o kemiji, smatra Profitt, ali dodaje da će napori da se uklone klorofluorougljici uroditi plodom za nekoliko desetljeća te da će do 2050. ozonski omotač u stratosferi biti jednak onome prije pojave ozonske rupe.