Scientists at the British Antarctic Survey have discovered a new threat to the stability of Antarctic ice sheets. Their research, published in Nature Geoscience, reveals that warm seawater can seep between the land and the ice sheet resting on it, causing increased melting in areas called grounding zones. Alex Bradley, the study’s lead author, explains that this process can lead to a “tipping point-like” behavior.
A very small change in ocean temperature can cause a very big increase in grounding zone melting, leading to significant changes in ice flow,” he says. The study suggests that current climate models may be underestimating the impact of global warming on ice melt and sea level rise. The melting in the grounding zones creates new cavities that allow further ingress of warm water, causing more melting and larger cavities.
This mechanism, currently missing from IPCC models, may explain why ice sheets in Antarctica and Greenland are shrinking faster than anticipated.
Antarctic ice sheet instability concerns
This is missing physics, which isn’t in our ice sheet models.
They don’t simulate melting beneath grounded ice, which we think is happening. We’re working on integrating that into our models now,” Bradley concludes. The findings highlight the importance of understanding all the factors contributing to ice melting to predict future sea level rise accurately.
With every tenth of a degree of ocean warming, the risk of passing this tipping point increases. The study emphasizes the need for dramatic action to restrict warming and prevent this tipping point from being passed. By cutting emissions to net zero by 2050, as recommended by the IPCC, humanity could avoid this worst-case scenario and other climate disasters.
