Lo scioglimento dei ghiacci dell'Antartico occidentale sta accelerando sotto l'effetto del riscaldamento climatico, secondo due studi pubblicati lunedì. Gli autori lo definiscono ormai "irreversibile" e lanciano l'allarme, prevedendo un sensibile innalzamento degli oceani.
La prima delle due ricerche, apparsa nelle Geographical Research Letters, si basa su 40 anni di osservazioni nel Mare di Amundsen. I sei grandi ghiacciai di quella regione contengono abbastanza acqua da far salire il livello del mare di 1,2 metri: ogni anno ne rilasciano una quantità pari all'intera banchisa della Groenlandia e le previsioni finora considerate valide (18-59 centimetri di incremento negli oceani entro il 2100) andrebbero corrette al rialzo.
A questo ritmo, la perdita di superficie gelata dovrebbe proseguire per almeno un secolo. Per la seconda ricerca, apparsa su Science, si assisterà poi a un'accelerazione repentina: tra 200-500 anni si arriverà al collasso del Thwaites, il ghiacciaio cardine dell'intero sistema, che minerebbe l'insieme della calotta.
ATS/pon
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