La NASA ha pubblicato un'animazione che mostra il declino dei ghiacci perenni nel Circolo Polare Artico tra il 1984 e il 2019. Il ghiaccio perenne può crescere fino a quattro metri di spessore ed è la porzione di ghiaccio marino che sopravvive alla stagione di fusione estiva.
L'animazione mostra la variabilità stagionale del ghiaccio, che cresce nell'inverno artico e si scioglie in estate. Oltre a questo, sono indicati anche i cambiamenti di anno in anno e l'età del ghiaccio marino in diversi colori. Il ghiaccio marino stagionale è mostrato in blu, mentre il ghiaccio di quattro anni o più vecchio è mostrato in bianco.
Secondo i dati, nella prima settimana di gennaio del 1988, 3'121'00 di chilometri quadrati erano coperti da ghiaccio marino di almeno quattro anni di età. Questa cifra è drasticamente diminuita con appena 116'000 chilometri quadrati coperti nel gennaio del 2019.
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