Antarctica will be the largest source of future rise in sea level yet scientists know little about how this will unfold. New research shows how the Antarctic ice sheet advanced and retreated over the past 10,000 years.
Antarctica has the world’s largest single mass of ice: the Antarctic ice sheet. The glacier is several kilometers thick and covers solid land including entire mountain ranges.
The Antarctic ice sheet “flows” over the land from its interior and towards the surrounding ocean. It remains a solid mass but its shape slowly deforms as the ice crystals move around.
As the ice sheet flows outward, snowfall replenishes it. This cycle is supposed to remain in balance as the ice sheet gains the same amount of ice as it’s losing to the ocean each year.
However, satellites confirm that the ice sheet is currently not in balance as it has lost more ice than it has gained over the last 40 years resulting in global sea level rise.
To look further back in time – before satellites – they needed natural archives such as ice cores, rocks and sediment cores.
What was striking was a period of ice loss that took place in all regions of Antarctica about some 10,000 to 5,000 years ago which resulted in many meters of sea-level rise globally.
However, in some regions of Antarctica, this ice loss was then followed by ice gain during the past 5,000 years and a corresponding global sea-level fall as the ice sheet margin advanced to where it is today.
The study shows that the period of ice loss from 10,000 to 5,000 years ago was rapid and occurred at a similar rate to the most dramatically changing parts of the Antarctic ice sheet today.
https://phys.org/news/2022-07-antarctic-ice-sheet-advanced-retreated.html