Antarctica is losing weight, allowing the continent to rise out of the ocean, much like a sponge that was once crushed and is now free to expand again.
This weight is his ice.
This process is called post-glacial uplift, and new research suggests it will have a huge impact on future sea-level rise. It could reduce Antarctica’s contribution by up to 40 percent, or make the situation much worse, depending on how much of the heat-trapping, ice-melting fossil fuels we continue to release.
“With nearly 700 million people living in coastal areas and the potential cost of sea level rise expected to reach trillions of dollars by the end of the century, understanding the domino effect of Antarctic ice loss is critical,” says Natalya Gomez, a glaciologist at McGill University.
And in recent years, Antarctica’s ice has remained stubbornly low.
Gomez and his colleagues studied the Earth’s mantle beneath the Antarctic ice sheet and found that it was particularly soft in some key areas. Seismic data revealed that this high level of viscosity is behind the land’s surprisingly rapid rise.
“Our measurements show that the solid earth that forms the base of the Antarctic ice sheet is changing shape surprisingly quickly,” says Terry Wilson, a geologist at Ohio State University.
“Land uplift due to reduced surface ice occurs over decades rather than thousands of years.”
The team then used 3D modeling to simulate sea level rise due to the changing landmass of Antarctica under different scenarios. If warming levels remain low, sea levels could rise by up to 1.7 meters by 2500, but this figure could reach 19.5 meters if we continue to allow global warming to intensify unabated.
That’s because when ice melts faster than it rises, more water ends up being expelled into the oceans. But if we can slow down that melting, rising land will lift some of the ice out of warmer ocean waters, allowing it to persist longer.
“This study marks a step forward in our ability to better predict the impacts of climate change on sea level rise and inform effective environmental policy,” said Rob DeConto, a glaciologist at the University of Massachusetts.
Since the Earth is not a perfectly smooth sphere, different parts of our planet will experience unique impacts on sea level due to gravitational, rotational, and geological peculiarities.
“Our results confirm recent findings that low-latitude islands and coastal sites already affected by sea level rise will experience above-average sea level rise associated with Antarctic ice loss, regardless of the ice loss scenario,” Gomez and his team explain.
“This finding highlights the climate injustice towards nations with low emissions, while their exposure and vulnerability to sea level rise are high.”
The researchers warn of a large uncertainty in the model, particularly because of the lack of seismic data from West Antarctica. And these estimates don’t even take into account what’s happening with the ice in Greenland and the world’s mountains.
Due to the current abnormal conditions in the #Arctic and #Antarctic, the total global sea ice extent is at its lowest level for the period and is nearly *4 million square kilometres* below the 1981-2010 average…
More charts: zacklabe.com/global-sea-i…
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— Zack Labe (@zlabe.bsky.social) July 30, 2024 at 10:45 am
“To document how quickly our world is changing, it is very important that we continue to improve our ability to make more certain predictions, which is the only way we can meaningfully care for our future,” Wilson says.
Rising sea levels are already impacting low-lying islands like Kiribati. Most of South Tarawa is less than 3 metres above sea level, where villagers in Temaiku are trying to hold back the ocean with sandbags, but these were washed away earlier this year, flooding homes and contaminating farmland and water wells with salt.
Meanwhile, wetlands are caught between rising seas and human infrastructure like roads. The loss of these ecosystems, which filter water and control erosion, means that rising sea levels will hit these areas even harder.
“Reducing greenhouse gas emissions will allow solid Earth rebound to play a greater role in preserving more of the Antarctic ice sheets and avoiding the most severe and inequitable impacts of future climate change on global coasts,” Gomez and colleagues conclude.
This research was published in Scientific progress.
