'Melting of Antarctic ice shelves to double by 2050'

The melting of Antarctic ice shelves will double by 2050 and by 2100, melting may surpass all predictions if greenhouse gas emissions continue at the present rate, a new study has warned.

Ice shelves are the floating extensions of the continent's massive land-based ice sheets.

While the melting or breakup of floating ice shelves does not directly raise sea level, ice shelves do have a "door stop" effect.

They slow the flow of ice from glaciers and ice sheets into the ocean, where it melts and raises sea levels.

"Our results illustrate just how rapidly melting in Antarctica can intensify in a warming climate," said Luke Trusel, lead author and post-doctoral scholar at the Woods Hole Oceanographic Institution (WHOI), a non-proft organisation based in Massachusetts.

"This has already occurred in places like the Antarctic Peninsula where we have observed warming and abrupt ice shelf collapses in the last few decades," he added.

The projections show that similar levels of melt may occur across coastal Antarctica near the end of this century, raising concerns about future ice shelf stability.

To study how melting evolves over time and to predict future ice sheet melting along the entire Antarctic coastline, the scientists combined satellite observations of ice surface melting with climate model simulations.

The results indicate a strong potential for the doubling of Antarctica-wide ice sheet surface melting by 2050.

By 2100, ice sheet surface melting approaches or exceeds intensities associated with ice shelf collapse in the past.

"The data clearly shows that the trajectory of greenhouse gas emissions over the coming century have an enormous control over the future fate of surface melting of Antarctic ice shelves," the authors commented.

The study appeared in the journal Nature Geoscience.