Antarctica is shedding weight, allowing the continent to rise from the ocean like a once-squished sponge now free to expand again. This process, called post-glacial uplift, could have a massive impact on future global sea level rise. Depending on fossil fuel emissions, it could reduce Antarctica’s contribution by up to 40 percent or make things worse.
With nearly 700 million people living in coastal areas and the potential cost of sea-level rise reaching trillions of dollars by the end of the century, understanding the domino effect of Antarctic ice melt is crucial,” said McGill University glaciologist Natalya Gomez. Gomez and colleagues examined Earth’s mantle beneath the Antarctic ice sheet and found it particularly squishy in some key areas. Seismic data revealed that this high level of viscosity is creating an unexpectedly fast rise in the land.
Our measurements show that the solid earth that forms the base of the Antarctic ice sheet is changing shape surprisingly quickly,” said Ohio State University geologist Terry Wilson. The land uplift from reduced ice on the surface has been happening for decades rather than thousands of years.
Using 3D modeling, the team simulated sea level rise due to Antarctica’s changing landmass across different scenarios. If warming levels are kept in check, sea levels could rise up to 1.7 meters (5.6 feet) by 2500, but if current trends continue, they could be as high as 19.5 meters.
This is because when ice sheet retreat outpaces uplift, more water is expelled into the oceans. However, slowing down the melt could allow the rising land to lift some of the ice away from warmer ocean waters, preserving it for longer.
Coastal impacts from Antarctic ice melt
This study marks a breakthrough in our ability to better predict rising seas’ impacts and inform effective environmental policy,” said University of Massachusetts glaciologist Rob DeConto. Sea level rise projections from 2000 to 2150 vary greatly under low and high emission scenarios. Different parts of Earth will experience unique sea level impacts due to gravitational, rotational, and geological factors.
“Our results further support that low-latitude islands and coastal sites already being affected by sea level rise will experience higher than average sea level rise associated with Antarctic ice loss, regardless of the ice loss scenario,” said Gomez and her team. The researchers caution that there is still a lot of uncertainty in the model, mainly due to the lack of seismic data from West Antarctica. These estimates also don’t factor in other significant changes occurring in the Arctic and Antarctic.
To document how fast our world is changing, it’s very important to continue advancing our ability to make predictions that are more certain, which is the only path that will allow us to tend to our future in a meaningful way,” said Gomez. Some regions, like Kiribati, are already feeling the effects. Most island nations are less than 3 meters above sea level, and flooding has tainted crops and water supplies with salt.
Losing these ecosystems will mean greater sea level rises, which will hit these areas even harder. However, the rebound of the solid Earth could play a greater role in preserving more of the Antarctic ice sheets and potentially avoiding the worst impacts of future climate change on global coastlines.
Noah Nguyen is a multi-talented developer who brings a unique perspective to his craft. Initially a creative writing professor, he turned to Dev work for the ability to work remotely. He now lives in Seattle, spending time hiking and drinking craft beer with his fiancee.
