Pack ice and huge icebergs in Antarctic waters near Commonwealth Bay, Antarctica (Getty)

Ice is melting in the western Antarctic at an unstoppable pace, US scientists say, warning that the discovery holds major consequences for global sea level rise in the coming decades.

They say the speedy melting means prior calculations of sea level rise worldwide made by the Intergovernmental Panel on Climate Change will have to be adjusted upwards.

"A large sector of the West Antarctic ice sheet has gone into a state of irreversible retreat. It has passed the point of no return," said Eric Rignot, professor of Earth system science at the University of California Irvine. Read more.

NASA: West Antarctica Glaciers - Past the point of no return