West Antarctica’s ice sheet was smaller thousands of years ago – here’s why this matters today

As the climate warms and Antarctica’s glaciers and ice sheets melt, the resulting rise in sea level has the potential to displace hundreds of millions of people around the world by the end of this century.

A key uncertainty in how much and how fast the seas will rise lies in whether currently “stable” parts of the West Antarctic Ice Sheet can become “unstable”.

One such region is West Antarctica’s Siple Coast, where rivers of ice flow off the continent and drain into the ocean.

This ice flow is slowed down by the Ross Ice Shelf, a floating mass of ice nearly the size of Spain, which holds back the land-based ice. Compared to other ice shelves in West Antarctica, the Ross Ice Shelf has little melting at its base because the ocean below it is very cold.

Although this region has been stable during the past few decades, recent research suggest this was not always the case. Radiocarbon dating of sediments from beneath the ice sheet tells us that it retreated hundreds of kilometres some 7,000 years ago, and then advanced again to its present position within the last 2,000 years.

Figuring out why this happened can help us better predict how the ice sheet will change in the future. In our new research, we test two main hypotheses.

- Read Dan Lowry's full article in The Conversation.