In a forecast study, researchers found that 34% of the area of all Antarctic ice shelves measuring about half a million square kilometers could destabilize if world temperatures were to rise by 4 degrees. About 67% of the ice shelf area on the Antarctic Peninsula would be in danger of destabilization under this scenario, researchers said.
Ice shelves are permanent floating platforms of ice attached to areas of the coast, formed where glaciers flowing out of the land meet the ocean. They can help curb the rise in global sea levels by acting as a dam and reducing the flow of melting ice and water to the oceans.
Every summer, ice melts on the surface of ice shelves and runs into smaller holes in the snow below, where it usually freezes again. But when there is a lot of melting and a little snowfall, this water instead accumulates on the surface of the ice or flows out into cracks. This deepens and expands the gaps, causing the shelf to crack and collapse in the ocean.
“Ice shelves are important buffers that prevent glaciers on land from flowing freely into the ocean and contribute to rising sea levels. When they collapse, it is as if a giant cork is removed from a bottle, allowing unimaginable amounts of water from glaciers to flowing into the ocean., “examined lead author Ella Gilbert, climate scientist at the University of Reading̵
Gilbert told CNN that low-lying coastal areas, especially small island states like Vanuatu and Tuvalu in the South Pacific, are most vulnerable to global sea level rise.
“Coastal areas around the world, however, would be vulnerable, and countries with fewer resources available to mitigate and adapt to sea level rise will see worse consequences,” she said.
In the new study, which used high-resolution regional climate models to predict the effect of increased melting and water runoff on ice shelf stability, researchers say a limiting temperature rise to 2 degrees Celsius rather than 4 degrees Celsius would halve the area at risk potentially avoiding significant sea level rise.
The Intergovernmental Panel on Climate Change concluded in a milestone report that we only have until 2030 to drastically reduce our dependence on fossil fuels and prevent the planet from reaching the crucial threshold of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels .
Global net emissions of carbon dioxide would have to fall by 45% from 2010 levels by 2030 and reach “net zero” around 2050 to keep warming around 1.5 degrees Celsius.
“The results highlight the importance of limiting global temperature rises as described in the Paris Agreement if we are to avoid the worst consequences of climate change, including sea level rise,” Gilbert added.
In the Paris Agreement, 197 countries agreed to the goal of keeping global temperatures “well below” 2 degrees Celsius above pre-industrial levels and continuing efforts to limit it to 1.5 degrees Celsius.
Gilbert told CNN that rising temperatures mean melting is occurring more often and more intensely.
Researchers identified four ice shelves that would be threatened by a warmer climate: the ice shelves Larsen C, Shackleton, Pine Island and Wilkins, which are vulnerable due to their geography, and the runoff predicted in these areas.
Larsen C is the largest remaining ice shelf on the Antarctic Peninsula, and the Pine Island Glacier has received much attention in recent years because it has melted rapidly in response to climate change, Gilbert said.
If these ice shelves all collapsed, which is not guaranteed, the glaciers they are currently holding back would flow into the ocean and contribute to an increase in sea level – potentially by tens of thousands, she explained.
The study was published Thursday in the journal Geophysical Research Letters.