Antarctica is losing its ice, causing the continent to rise from the ocean. This phenomenon, known as post-glacial uplift, could drastically affect future global sea levels. The implications of this process are profound and depend heavily on human actions concerning fossil fuel emissions.
THE WEIGHT OF ICE
Antarctica’s weight loss comes from melting ice. The process of post-glacial uplift means the continent rises as the heavy ice melts away, similar to a sponge expanding after being squeezed. New research indicates this uplift could either reduce Antarctica’s contribution to sea-level rise by up to 40% or exacerbate the situation, depending on future fossil fuel emissions.
McGill University glaciologist Natalya Gomez and her team studied the Earth’s mantle beneath the Antarctic ice sheet. They found that certain areas are especially squishy, causing the land to rise faster than expected. Seismic data revealed high levels of viscosity, leading to this rapid uplift.
Ohio State University geologist Terry Wilson noted, “Our measurements show that the solid earth beneath the Antarctic ice sheet is changing shape surprisingly quickly.” He explained that the uplift, resulting from reduced ice, is happening over decades rather than thousands of years.
3D MODELING AND SCENARIOS
Researchers used 3D modelling to simulate sea level rise due to Antarctica’s changing landmass under various scenarios. If global warming is controlled, sea levels could rise up to 1.7 meters by 2500. However, if warming continues unchecked, this could reach as high as 19.5 meters.
IMPACT ON SEA LEVELS
When the ice sheet retreat outpaces the land uplift, more water is expelled into the oceans. Slowing the melt allows the rising land to lift some ice away from warmer waters, preserving it longer.
POLICY IMPLICATIONS
CLIMATE INJUSTICE
Gomez and her team emphasized the climate injustice faced by nations with low emissions but high vulnerability to sea level rise. Their findings suggest low-latitude islands and coastal sites already affected by rising seas will see higher-than-average increases due to Antarctic ice loss.
UNCERTAINTY AND FUTURE RESEARCH
Researchers caution there is still uncertainty in the models, particularly due to limited seismic data from West Antarctica. Additionally, these estimates don’t account for ice changes in Greenland and other mountainous regions. Wilson stressed the importance of improving predictive abilities to better manage future changes.
REAL-WORLD IMPACTS
Rising sea levels are already affecting low-lying islands like Kiribati. In South Tarawa, where most land is less than 3 meters above sea level, villagers have struggled to hold back the ocean with sandbags, which were washed away, flooding homes, and contaminating crops and water supplies with salt.
Wetlands, trapped between rising water and human infrastructure, face significant threats. These ecosystems filter water and control erosion, meaning their loss could exacerbate the effects of sea level rise on coastal areas.
Gomez and colleagues concluded that reducing greenhouse gas emissions is crucial. This reduction will allow the solid Earth’s rebound to play a greater role in preserving Antarctic ice sheets and mitigating the worst impacts of future climate change on global coastlines.
Understanding the domino effect of Antarctic ice melt is crucial, with nearly 700 million people living in coastal areas. Effective environmental policies based on this research could save trillions of dollars and protect countless lives.
This research was published in Science Advances.
