evidence: Third of Antarctic ice shelf area at risk of collapse as planet warms More than a third of the Antarctic's ice shelf area could be at risk of collapsing into the sea if global temperatures reach 4°C above pre-industrial levels, new research has shown. [...] It found that 34% of the area of all Antarctic ice shelves—around half a million square kilometers—including 67% of ice shelf area on the Antarctic Peninsula, would be at risk of destabilization under 4°C of warming. Limiting temperature rise to 2°C rather than 4°C would halve the area at risk and potentially avoid significant sea level rise.