Context: Recently, the National Centre for Polar and Ocean Research has predicted an increase in the expansion of the Amery Ice Shelf boundaries in Antarctica.
Key Findings of the study

• The prediction is made by NCPOR, Goa based on a 16-year-long satellite-based observation that covered an area of 60,000 sq km across the AIS.
• There would be a 24 percent increase in the expansion of the Amery Ice Shelf (AIS) boundaries in Antarctica by 2021 and another 24 percent by 2026 from its 2016 positions.
• The scientists observed a spatio-temporal change in the ice shelf as reflected by the extension of the Pridze and Mackenzie and the extension of a 200-km stretch between Mackenzie Bay and the Sandefjord Bay.
• It becomes clear from the study that the AIS is losing its stability owing to the impact of a downstream giant glacial drainage system over the past 19 years, thereby advancing the ice shelf boundaries due to higher freezing rates than basal melting.

Significance of the study

• NCPOR observations revealed a critical cooling of the sea surface temperature, resulting in an advancement of the ice shelf by 88 per cent in the past 15 years.
• These changes would contribute in a major way to climate variability.
• The study clearly demonstrated the future dynamism of ocean heat fluctuation and Antarctic Amery ice shelf mass shifting-extent.
• This study would help in better understanding of the ongoing changes in the ocean and atmospheric forces.

About Amery Ice Shelf (AIS)

• The Amery Ice Shelf is a broad ice shelf in Antarctica at the head of Prydz Bay between the Lars Christensen Coast and Ingrid Christensen Coast.
• It is part of Mac. Robertson Land.
• The name “Cape Amery” was applied to a coastal angle mapped on February 11, 1931.
• The AIS is one of the largest glacier drainage basins in the world, located on the east coast of Antarctica, at about 70ºS Latitude, 70ºE Longitude.
• The AIS dynamics and mass balance help in understanding the changes in the global climate scenario.

About Ice shelves

• The floating sheets of ice called ‘ice shelves’ play a multi-faceted role in maintaining the stability of a glacier.
• Ice shelves connect a glacier to the landmass.
• The ice sheet mass balance, sea stratification, and bottom water formation are important parameters for the balancing of a glacier.
• Latent and sensible heat processes do play important roles here. 
• The insulation of ice shelves from atmospheric forcing is dependent on a temperature gradient that the ocean cavity beneath the ice shelves provides.
• It is the pressure exerted by the ice shelves upon the ocean cavity that determines this temperature gradient.
• There is always a stress on the sea ice and ice sheets themselves play an indirect role in reducing the amplitude of the ocean swell.
• This is assisted by the freezing atmospheric temperature, which is capable of promoting a change in the morphology of ice shelves.