Research has found that Antarctic ice shelves contain 57 percent of all meltwater in the form of slush during summer months. Slush, which is water-saturated snow, along with pooled meltwater, produces 2.8 times more meltwater than traditional climate models have predicted because it absorbs more heat compared to ice or snow.
The research team, led by the University of Cambridge, utilized artificial intelligence to study the effects of slush on ice shelves. According to their findings, this could have significant implications for ice shelf stability and sea level rise. The study highlights that regional climate models do not accurately account for slush, indicating a need for model updates.
A warming climate leads to the formation of meltwater on ice shelves, and previous research has shown that surface meltwater lakes can destabilize ice shelves and potentially cause them to collapse, which directly affects sea levels. Mapping slush is challenging with satellite imagery because it can resemble other features, such as cloud shadows, making it difficult to distinguish.
Cambridge researchers, collaborating with teams from the University of Colorado Boulder and Delft University of Technology, used NASA's Landsat 8 satellite data and machine learning to monitor slush and meltwater across 57 Antarctic ice shelves from 2013 to 2021. They found that pools and lakes account for only 43 percent of meltwater, with the remaining 57 percent in slushy areas, accelerating melt rates.
Dr. Rebecca Dell noted that slush had not previously been mapped on a large scale, meaning that over half of the surface meltwater had been overlooked until now. The study also revealed that slush absorbs more heat due to its less reflective surface, leading to increased snowmelt. Current climate models, which do not account for slush, have likely underestimated ice sheet melting and ice shelf stability. The study, published in Nature Geoscience, emphasizes that rising sea levels due to climate change pose a significant risk to coastal areas.
