Scientists have calculated the ice lost from the Amundsen Sea Embayment, the fastest changing Antarctic region and lying in West Antarctica, to be more than 3,000 billion tonnes over a 25-year period.
The study by University of Leeds, UK, shows that West Antarctica saw a net decline of 3,331 billion tonnes of ice between 1996 and 2021, contributing over nine millimetres to global sea levels.
The study said that if all of this lost ice was piled on London, it would stand over 2 km tall. If it were to cover Manhattan, it would stand at as tall as 137 Empire State Buildings placed on top of one another.
"Changes in ocean temperature and circulation appear to be driving the long-term, large-scale changes in West Antarctica ice sheet mass. We absolutely need to research those more because they are likely to control the overall sea level contribution from West Antarctica," said Benjamin Davison, lead researcher of the study, University of Leeds.
The twenty major glaciers, which form the Amundsen Sea Embayment in West Antarctica, play a key role in contributing to the world's oceans' levels. They together are more than four times the size of the UK.
If all the water held in the snow and ice were to drain into the sea, the study said, global sea levels could increase by more than one metre.
The findings are published in the journal Nature Communications.
Davison calculated the "mass balance" of the Amundsen Sea Embayment, which describes the balance between mass of snow and ice gain from snowfall and mass lost through calving, where icebergs form at the end of a glacier and drift out to sea.
The Embayment loses mass overall when the rate of calving is higher than that of ice being replaced by snowfall, thereby, contributing to global sea level rise.
Similarly, when snowfall supply drops, the Embayment can lose mass overall, again, contributing to sea level rise.
"The 20 glaciers in West Antarctica have lost an awful lot of ice over the last quarter of a century and there is no sign that the process is going to reverse anytime soon although there were periods where the rate of mass loss did ease slightly," said Davison.