Antarctica's protective ice barriers are melting at double the pace

Scientists from The University of Edinburgh have made a worrying discovery about Antarctica. The huge platforms of ice that surround the continent are getting thinner much faster than ever before. This accelerated melting increases the planet’s vulnerability to the effects of climate change.

Role of ice shelves

In Antarctica, massive sheets of ice called ice shelves stretch out from the land, covering the ocean. These impressive formations start as glaciers, which are slow-moving rivers of ice flowing from the center of the continent towards the coast. When they reach the coast, instead of stopping, the glaciers keep spreading out over the water, eventually forming these ice shelves.

Ice shelves play a critical role in the environment of Antarctica, serving as natural barriers that slow down the flow of ice from land into the ocean. This process is essential for maintaining the stability of the entire ice sheet and keeping sea levels stable around the world.

Pinning points

For nearly 50 years, scientists have been analyzing satellite images of Antarctica. They were particularly interested in tracking the fate of “pinning points,” underwater mountains that act like anchors, keeping the ice shelves stable. 

By carefully examining the images, they observed changes in these pinning points over time. The findings were alarming: the crucial anchors are disappearing, suggesting that the ice shelves are thinning and becoming less stable. 

Historical data of ice shelves

The study revealed a concerning trend of ice shelves melting over time.

1973-1989

The thinning of ice shelves was limited to small, localized areas, primarily concentrated in the Amundsen Sea Embayment and the Wilkes Land coastline.

During this period, only 15% of pinning points showed a reduction in size. This initial phase suggested a period of relative stability for Antarctic ice shelves, with minimal loss of their ability to hold back ice flow (buttressing potential).

1989 and 2000

The picture changed significantly during this time. Thinning became more widespread, indicating an acceleration in the deterioration of ice shelves. This period also saw a jump in the proportion of pinning points losing size, with the number rising to 25%.

The rapid increase in thinning suggested the ice shelves were becoming more vulnerable to climate change, potentially leading to faster movement of ice into the ocean.

2000 to 2022

The most recent period continued the worrying trend. Thinning remained widespread, affecting even larger areas of ice shelves. Notably, the percentage of pinning points showing a decrease in size further increased to a concerning 37%. 

This significant loss highlights an accelerated degradation of ice shelf stability. The weakening of pinning points directly impacts the ice shelves’ ability to hold back ice, potentially leading to increased ice discharge and, consequently, a greater contribution to rising sea levels.

The role of climate change

Rising temperatures due to climate change are having a significant negative impact on Antarctica’s ice shelves. These massive platforms of ice are being attacked from multiple angles.

Hotter air temperatures directly melt the surface of the ice shelves. This melting from above thins the ice, further reducing its ability to act as a barrier against the land ice flowing into the ocean.

Warming ocean temperatures are causing the water surrounding and beneath the ice shelves to become warmer. The warmer water melts the ice from the bottom, weakening its structure and making it easier to break apart.

Moreover, climate change is also altering snowfall patterns over Antarctica. While increased snowfall might seem helpful initially, it can add too much weight and cause the shelves to collapse. Conversely, decreased snowfall can reduce the overall mass of the ice shelves, making them less effective as barriers.

These combined effects highlight how climate change poses a major threat to the stability of Antarctica’s ice shelves.

Urgent need for action

“What we are seeing around Antarctica is a sustained attack by climate warming to the buttresses, that slow the conversion of ice melting, into global sea-level rise. This reinforces the need for us to take action where we can to reduce global carbon emissions,” said study co-author Professor Robert Bingham.

Potential strategies include switching to renewable energy, improving energy efficiency, and choosing sustainable transportation options. Additionally, supporting ongoing research is vital to predict future changes and to inform crucial policy decisions.

The study is published in the journal Nature. 

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