Antarc­tic ice

Australian Geographic - - Contents -

THE STA­TIS­TICS never fail to con­found: 90 per cent of the planet’s fresh wa­ter is trapped in the 14 mil­lion square kilo­me­tres of Antarc­tic ice sheet – roughly 24.5 mil­lion cu­bic kilo­me­tres of fresh wa­ter. Since Antarc­tica’s link with

South Amer­ica was bro­ken 20 mil­lion years ago, the ice has grown, snowflake upon snowflake, trans­muted over ge­o­log­i­cal time to glacial ice. Grav­ity moves this ice to­wards Antarc­tica’s coasts, where su­per-cooled salt wa­ter freezes, thaws and freezes, year on year, nearly dou­bling the sur­face area of Antarc­tic ice at its most northerly point. One time-scale is ge­o­log­i­cal, the other sea­sonal. One is a fresh­wa­ter phe­nom­e­non, the other ma­rine. To­gether, they are the story of Antarc­tica’s ice.

ANTARC­TIC CONTINENT PER­MA­NENT ICE SHEET: 14,000,000sq.km PACK ICE EXTENT IN SUMMER: + 3,000,000sq.km PACK ICE EXTENT IN WIN­TER: + 20,000,000sq.km SIZE OF AUS­TRALIAN CONTINENT: 7,700,000sq.km

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