The West Antarctic Ice Sheet is considered highly vulnerable to rising temperatures, especially in the area around the Thwaites Glacier. The entire Antarctic ice sheet (East and West) contains enough ice to raise global sea-levels by about 58m (190ft) if it all melted. Most of the ice is held in East Antarctica, which has been relatively stable in recent years, and is not expected to collapse in the near future. However, a sizeable portion – enough to raise sea-levels by around 5m (16ft) – is held in West Antarctica, which is considered less stable and has been losing mass in recent decades. Let me repeat that, the unstable West Antarctic Ice Sheet contains enough ice which, if it totally melts, would raise sea-levels by 16ft, worldwide.
In 2021, the UN’s climate body, the Intergovernmental Panel on Climate Change (IPCC), released its latest estimates of future sea-level rise. It projected a global average sea-level rise of between 0.28m and 1.01m by 2100 – one key reason being the melting of glaciers and ice sheets in Antarctica.
Sea-level rises of around a metre may not sound like much, but even these increases would put hundreds of millions of people worldwide at risk of coastal flooding. Imagine what a rise of 16 feet would do. It may take a hundred years, or more, but the results will be catastrophic across the world; most of Florida will disappear, virtually all of Bangladesh will be under water, most Pacific Islands will disappear and every coastline in the world will be drastically altered.
Ice shelves are the parts of glaciers that extent out into the sea in Antarctica. When they melt, the glacier moves towards the sea. The faster the ice shelves melt, the more rapidly the glacier moves towards the sea, and melts itself.
“Our findings seem to increase the likelihood that current estimates of sea-level rise will be exceeded,” reports Dr. Kaitlin Naughten of the British Antarctic Survey (BAS). Amundsen Sea, off the coast of West Antarctica, will warm roughly three times faster than the historical rate through the rest of this century, according to a recent study. This will lead to much more rapid melting of ice shelves and, consequently, the glaciers. Dr. Naughten believes this will still happen even if humanity takes strong steps to slow global warming. However, this frightening conclusion is not a reason to avoid moving away from fossil fuels, Dr. Naughten stresses. “What we do now will help to slow the rate of sea-level rise in the long term,” she explains.
Unlike most of East Antarctica, much of the West Antarctic continent sits below sea-level. This means that glaciers may retreat into deeper and deeper waters, accelerating the loss of ice.
This is the major concern with Thwaites Glacier that flows into the Amundsen Sea. Thwaites, sometimes referred to as the “doomsday glacier” because it would raise global sea-levels by around 65cm (25in) if it collapsed entirely, is highly vulnerable to warming. Its grounding line – the point where ice loses contact with the bedrock and starts to float – is already retreating by more than 1 kilometer per year, in some places.
As was mentioned above, floating ice shelves act as a brake on the flowing ice from the glaciers behind them. “This study worsens the outlook for Thwaites Glacier, as we simulate rapidly increasing melting beneath its connected ice shelf,” Dr. Naughten reported. “The processes triggered by faster ice shelf melting could lead to the collapse of the West Antarctic Ice Sheet”, she suggests.
It is well-established that sea-levels will continue to rise in the coming decades and centuries. This is because ice sheets take a long time to fully adjust to changes to the rapid warming of recent years, with further temperature rises to come. This latest study adds weight to the idea that sea-levels may rise faster than previously assumed as a result of increased ice shelf melt, to which societies worldwide will have to adapt. “It looks like we’ve lost control of melting of the West Antarctic Ice Sheet,” concludes Dr. Naughten.
“This is a sobering piece of research,” agrees Alberto Naveira Garabato, a professor in physical oceanography at the University of Southampton, who was not involved in the latest work.
However, researchers emphasise this is not a reason to give up tackling climate change. Steps taken to slow the loss of ice through cutting greenhouse gas emissions, could be crucial in giving societies time to prepare for, and adapt to, rising seas. “It should serve as a wake-up call,” Professor Naveira Garabato explains. “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.”
Let’s hope, for the sake of future generations, that someone with the power to make difficult decisions, reads, listens, understands, and acts on this frightening possibility…..perhaps it is more accurate to say “frightening, and inevitable, reality.
