In a predictive study, scientists found that 34% of all Antarctic ice shelves, which are roughly half a million square kilometers, could be destabilized if global temperatures rise by 4 degrees. Researchers said that about 67% of the ice shelf area on the Antarctic Peninsula would be at risk of destabilization under this scenario.
Glaciers are permanent floating platforms of ice attached to coastal regions, and they form where glaciers flowing from the ground meet the sea. It could help curb the rise in global sea levels by acting like a dam, slowing the flow of melting ice and water into the oceans.
Every summer, the ice at the surface of the ice shelves melts and flows into smaller gaps in the ice below, where it usually freezes again. But when there is a lot of melting and little snowfall, that water instead collects on the surface of the ice or flows into the cracks. This deepens and widens the cracks, causing the cliff to crack and collapse at sea.
“Ice shelves are important insulators that prevent glaciers on land from flowing freely into the ocean and contribute to sea level rise. When they collapse, it is like removing a giant cork from a bottle, allowing unimaginable amounts of water from the glaciers to flow into the sea,” she said Lead study author Ella Gilbert, a climate scientist in the Department of Meteorology at the University of Reading, said in a statement.
Gilbert told CNN that low-lying coastal areas, particularly small island states like Vanuatu and Tuvalu, in the South Pacific, are most at risk from global sea level rise.
“However, coastal areas around the world will be at risk, and countries with few resources available to mitigate and adapt to sea level rise will experience worse consequences,” she said.
In the new study, which used high-resolution regional climate modeling to predict the effect of increased melting and runoff on ice shelf stability, the researchers say limiting the temperature rise to 2 degrees Celsius instead of 4 degrees Celsius would cut the vulnerable area in half. Likely to avoid significant sea level rise.
The Intergovernmental Panel on Climate Change concluded in a landmark report that we only have until 2030 to dramatically reduce our dependence on fossil fuels and prevent the planet from reaching the critical threshold of 1.5 ° C (2.7 ° F) above pre-industrial levels.
The net global emissions of carbon dioxide must fall by 45% from 2010 levels by 2030 and reach ‘net zero’ around 2050 in order to keep warming at around 1.5 ° C.
“The results highlight the importance of limiting the rise in global temperatures as stipulated 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 to continue efforts to limit the temperature to 1.5 degrees Celsius.”
Rising temperatures mean melting is occurring more frequently and more intensely, Gilbert told CNN.
Researchers have identified four ice shelves that could be threatened by a warmer climate: Larsen C, Shackleton, Pine Island and Wilkins, which are ice shelves at risk due to their geography, and the expected runoff in those areas.
Gilbert said Larsen C is the largest remaining ice shelf on the Antarctic Peninsula, and the Pine Island glacier has garnered a lot of attention in recent years because it is melting rapidly in response to climate change.
She explained that if all those ice shelves collapsed, which is not guaranteed, the glaciers currently holding them back would flow into the ocean, contributing to sea level rise – perhaps by tens of centimeters.
The study was published Thursday in the journal Geophysical Research Letters.