‘Unimaginable amounts’ of water will flow into oceans if that temperature rise occurs and ice buffers vanish, warn UK scientists

A rift in the Larsen C ice shelf, Antarctica, revealed by British Antarctic Survey observations from February 2017. Photograph: British Antarctic Survey/AFP/Getty

More than a third of the vast floating platforms of ice surrounding Antarctica could be at risk of collapsing and releasing “unimaginable amounts” of water into the sea if global temperatures reach 4C above pre-industrial levels, UK scientists say.

Researchers from the University of Reading said that limiting the temperature rise to 2C could halve the area at risk and avoid a drastic rise in sea levels.

The findings, published in the journal Geophysical Research Letters, suggest that 4C warming could leave 34% of the area of all the Antarctic ice shelves – amounting to about half a million square kilometres – at the risk of collapse.

Ice shelves are permanent floating sheets of ice that connect to a landmass; most surround the coasts of Antarctica.