La riduzione del buco nell'ozono sta bloccando i cambiamenti nella circolazione dei venti dell'emisfero australe che stavano influenzando il clima di Sud America, Africa e Australia.
Questo grazie al protocollo di Montreal, un trattato internazionale che ha gradualmente eliminato l'uso di sostanze chimiche che riducono lo strato di questo gas nell'atmosfera. Lo indica la ricerca dell'università del Colorado Boulder e dell'Agenzia americana per l'atmosfera e gli oceani (NOAA).
Il buco dell'ozono, scoperto nel 1985, si forma ogni primavera nella fascia alta dell'atmosfera sopra l'Antartide. La riduzione del gas raffredda l'aria, rafforzando i venti del vortice polare, influenzando i venti fino allo strato più basso dell'atmosfera terrestre. Precedenti studi avevano collegato questo fenomeno ai cambiamenti climatici nell'emisfero australe, in particolare alle precipitazioni in Sud America, Africa orientale e Australia, e ai cambiamenti quelli delle correnti oceaniche.
ats/joe.p.
%20--%3e%3csvg%20version='1.1'%20id='Layer_1'%20xmlns='http://www.w3.org/2000/svg'%20xmlns:xlink='http://www.w3.org/1999/xlink'%20x='0px'%20y='0px'%20viewBox='0%200%20138.2%2048'%20style='enable-background:new%200%200%20138.2%2048;'%20xml:space='preserve'%3e%3cstyle%20type='text/css'%3e%20.st0{fill-rule:evenodd;clip-rule:evenodd;fill:%23AF001E;}%20.st1{fill-rule:evenodd;clip-rule:evenodd;fill:%23FFFFFF;}%20%3c/style%3e%3cpath%20class='st0'%20d='M0,48h138V0H0V48z'/%3e%3cpath%20class='st1'%20d='M9.3,31.7l-0.4,2.7C8.8,35,9,35.2,9.5,35.3c2,0.2,4,0.3,6.1,0.3c5.6,0,9.7-1.8,9.7-7.1c0-3.1-1.3-5.4-6-6.6%20l-2.6-0.7c-1.8-0.5-2.6-1-2.6-2.3c0-1.9,1.7-2.2,3.3-2.2c2.2,0,4.4,0.2,5.3,0.2c0.9,0.1,1.2,0,1.3-0.8l0.4-2.6c0-0.1,0-0.2,0-0.3%20c0-0.1-0.1-0.2-0.1-0.3s-0.1-0.1-0.2-0.2c-0.1,0-0.2-0.1-0.3-0.1c-2-0.2-4.1-0.3-6.1-0.3C11.8,12.4,9,14.9,9,19c0,3.6,2,5.8,5.4,6.7%20l2.6,0.7c2.1,0.6,3,1.2,3,2.5c0,2-1.3,2.3-4.6,2.3c-1.5,0-4-0.2-4.9-0.3C9.6,30.9,9.4,31,9.3,31.7'/%3e%3cpath%20class='st1'%20d='M36.4,23.6l-0.3,1.5C36,25.4,36,25.6,36,25.9c0,0.4,0.1,0.8,0.4,1.1l4.2,7.6c0.1,0.3,0.3,0.5,0.6,0.7%20c0.3,0.2,0.6,0.2,0.9,0.2h3.8c0.5,0,1.1-0.3,0.5-1.2l-5.1-8.6c1.7-1.1,3.6-2.6,3.6-6.1c0-4.4-2.5-6.9-7.9-6.9h-7.8%20c-0.7,0-0.9,0.2-0.9,1v20.8c0,0.7,0.2,1,0.9,1h3.2c0.7,0,0.9-0.2,0.9-1V16.8h3.3c2.1,0,3.1,0.8,3.1,2.8c0.1,0.6,0,1.2-0.3,1.6%20c-0.3,0.5-0.7,0.9-1.3,1.1C37.1,22.7,36.8,22.3,36.4,23.6z'/%3e%3cpath%20class='st1'%20d='M66.1,34V22.7c0-0.7-0.2-1-0.9-1h-5.8c-0.7,0-0.9,0.2-0.9,1v2.5c0,0.7,0.2,0.9,0.9,0.9h1.7v5%20c-0.6,0.1-1.1,0.1-1.7,0.1c-4.8,0-6-3.1-6-7.4c0-5.4,2-6.8,6.5-6.8c1.3,0,3.1,0.1,4.1,0.2c1,0.1,1.2,0,1.3-0.8l0.4-2.5%20c0.1-0.7,0-1-0.8-1.1c-1.8-0.2-3.6-0.3-5.4-0.2c-8.2,0-11.6,4.3-11.6,11.3s2.7,11.9,11.3,11.9c2,0.1,4,0,6-0.4%20C65.9,35.2,66.2,34.9,66.1,34'/%3e%3cpath%20class='st1'%20d='M74.9,31.7l-0.4,2.7c-0.1,0.5,0.2,0.7,0.6,0.8c2,0.2,4,0.3,6.1,0.3c5.6,0,9.7-1.8,9.7-7.1c0-3.1-1.3-5.4-6-6.6%20l-2.6-0.7c-1.8-0.5-2.6-1-2.6-2.3c0-1.9,1.7-2.2,3.3-2.2c2.2,0,4.4,0.2,5.3,0.2c0.9,0.1,1.2,0,1.3-0.8l0.4-2.6c0-0.1,0-0.2,0-0.3%20c0-0.1-0.1-0.2-0.1-0.3s-0.1-0.1-0.2-0.2c-0.1,0-0.2-0.1-0.3-0.1c-2-0.2-4.1-0.3-6.1-0.3c-5.8,0-8.6,2.6-8.6,6.6%20c0,3.6,2,5.8,5.4,6.7l2.6,0.7c2.1,0.6,3,1.2,3,2.6c0,2-1.3,2.3-4.6,2.3c-1.5,0-4-0.2-4.9-0.3C75.3,30.8,75,30.9,74.9,31.7'/%3e%3cpath%20class='st1'%20d='M93.1,31.7l-0.4,2.7c-0.1,0.5,0.2,0.7,0.6,0.8c2,0.2,4,0.3,6.1,0.3c5.6,0,9.7-1.8,9.7-7.1c0-3.1-1.3-5.4-6-6.6%20l-2.6-0.7c-1.8-0.5-2.6-1-2.6-2.3c0-1.9,1.7-2.2,3.3-2.2c2.2,0,4.4,0.2,5.3,0.2c0.9,0.1,1.2,0,1.3-0.8l0.4-2.6c0-0.1,0-0.2,0-0.3%20c0-0.1-0.1-0.2-0.1-0.3c-0.1-0.1-0.1-0.1-0.2-0.2c-0.1,0-0.2-0.1-0.3-0.1c-2-0.2-4.1-0.3-6.1-0.3c-5.8,0-8.6,2.6-8.6,6.6%20c0,3.6,2,5.8,5.4,6.7l2.6,0.7c2.1,0.6,3,1.2,3,2.6c0,2-1.3,2.3-4.6,2.3c-1.5,0-4-0.2-4.9-0.3S93.1,30.9,93.1,31.7'/%3e%3cpath%20class='st1'%20d='M120.2,23.6l-0.3,1.5c-0.1,0.3-0.1,0.5-0.1,0.8c0,0.4,0.1,0.8,0.3,1.1l4.2,7.6c0.1,0.3,0.3,0.5,0.6,0.7%20c0.3,0.2,0.6,0.2,0.9,0.2h3.8c0.5,0,1.1-0.3,0.5-1.2l-5.1-8.6c1.7-1.1,3.7-2.7,3.7-6.1c0-4.4-2.5-6.9-7.9-6.9H113%20c-0.7,0-0.9,0.2-0.9,1v20.8c0,0.7,0.2,1,0.9,1h3.2c0.7,0,0.9-0.2,0.9-1V16.8h3.3c2.1,0,3.1,0.8,3.1,2.8c0.1,0.6,0,1.2-0.3,1.6%20c-0.3,0.5-0.7,0.9-1.3,1.1C120.9,22.7,120.6,22.3,120.2,23.6'/%3e%3c/svg%3e)