The forthcoming dissolution of ice shelves in West Antarctica appears to be “unavoidable,” according to recent research carried out by British Antarctic Surveys. These ice platforms, which stretch from the primary ice mass into the ocean, act as vital barriers that contain the inland glaciers. However, the melting of these ice shelves can cause the glaciers behind them to accelerate, contributing more ice to the seas. [1]
The research indicates that the future ascent of sea levels could be higher than prior projections have indicated. “Our findings seem to increase the likelihood that [current] estimates [of sea-level rise] will be exceeded,” stated Dr Kaitlin Naughten of the British Antarctic Survey (BAS), the principal investigator of the study, in a conversation with the BBC.
Undeniable Acceleration in Ice Sheet Melting
In 2021, the United Nations’ climate arm, the Intergovernmental Panel on Climate Change (IPCC), published its most recent predictions concerning future sea-level increases. It estimated that by the year 2100, the worldwide average sea level would go up by 0.28m to 1.01m. One of the primary factors is the thawing of glaciers and ice masses. [2]
Even though a one-metre rise might not seem significant, such an elevation would jeopardise hundreds of millions of people globally due to coastal inundation. [3]
The IPCC also mentioned that larger increases are plausible owing to “ice-sheet-related processes that are characterised by deep uncertainty,” which were not explicitly accounted for in their assessments. [2]
A pivotal uncertainty is the interaction between ice sheets and the oceanic waters. This latest research, featured in the journal Nature Climate Change, is the inaugural study to directly model the impact of ocean warming on Antarctic ice shelves, under varying greenhouse gas emission scenarios. Greenhouse gases are primarily emitted through fossil fuel combustion, which is a leading driver of anthropogenic climate change. [1]
The study discovered that the Amundsen Sea, located off the coast of West Antarctica, is likely to warm at approximately triple the historical rate for the rest of this century, resulting in markedly increased ice shelf melting. [1]
Even if robust measures are undertaken to mitigate global warming, this situation will persist, according to the study. Nonetheless, Dr Naughten emphasises that we should not be deterred from reducing fossil fuel use.
“This study worsens the outlook for Thwaites Glacier, as we simulate rapidly increasing melting beneath its connected ice shelf,” she notes.
Further Study Required but Findings Are Significant
The researchers stipulate that additional inquiries are needed to bolster confidence in their conclusions. However, their findings hold significance because they elaborate on how the melting of ice shelves affects West Antarctica at large. [1]
The total ice content of the Antarctic continent could raise global sea levels by approximately 58m (190ft) if it were to fully melt. Most of this ice is located in East Antarctica, which has displayed relative stability lately and is not anticipated to disintegrate soon. [1]
Conversely, West Antarctica, containing enough ice to elevate sea levels by roughly 5m (16ft), has been losing mass and is deemed less stable. [1]
As glaciers in Antarctic territories typically flow towards the sea, they often stretch out into the ocean, creating ice shelves. These ice shelves serve a vital function in restraining the glaciers situated behind them. However, when these shelves melt due to warm ocean waters, this restraining effect diminishes, thereby accelerating the glaciers. [1]
The research accentuates that an increased rate of ice shelf melting “could lead to the collapse of the West Antarctic Ice Sheet,” but additional variables, such as snowfall and surface ice melt, will also influence how quickly sea levels ascend. [1]
A Call for Urgent Action
The research adds substance to the notion that future sea-level rise may exceed prior estimations. Societies worldwide will need to adjust to this accelerated rate of change.
“It looks like we’ve lost control of melting of the West Antarctic Ice Sheet,” concludes Dr Naughten.
Professor Alberto Naveira Garabato of the University of Southampton, who was not involved in this study, states, “This is a sobering piece of research”.
However, experts stress that it is not too late to act. Immediate steps to reduce greenhouse gas emissions could be pivotal in allowing societies more time to adapt to the challenges posed by rising sea levels.
“It should serve as a wake up call. We can still save the rest of the Antarctic Ice Sheet, containing about 10 times as many metres of sea-level rise, if we learn from our past inaction and start reducing greenhouse gas emissions now.” Explains Professor Naveira Garabato.
Source:
- British Antarctic Survey. (n.d.). Increased West Antarctic Ice Sheet melting ‘unavoidable’. [online] Available at: https://www.bas.ac.uk/media-post/increased-west-antarctic-ice-sheet-melting-unavoidable/ [Accessed 24 Oct. 2023].
- IPCC (2015). Chapter 4: Sea Level Rise and Implications for Low-Lying Islands, Coasts and Communities — Special Report on the Ocean and Cryosphere in a Changing Climate. [online] Ipcc.ch. Available at: https://www.ipcc.ch/srocc/chapter/chapter-4-sea-level-rise-and-implications-for-low-lying-islands-coasts-and-communities/.
- United Nations (2023). Climate Change-induced Sea-Level Rise Direct Threat to Millions around World, Secretary-General Tells Security Council | UN Press. [online] press.un.org. Available at: https://press.un.org/en/2023/sc15199.doc.htm.