New Modeling Of Antarctic Ice Shelf Loss: Imagine 843 Ice Cubes 1 Kilometer Per Side Disappearing Every Year
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Galton-Fenzi, a principal research scientist at the Australian Antarctic Division, led new research bringing together modelling work on this “basal melt rate” from nine groups around the world. “We need to know because the ocean-driven mass loss is one of the biggest uncertainties in Antarctica ice sheet projections and, therefore, in global sea level rise,” says Galton-Fenzi. Taking the nine different models together, Galton-Fenzi and colleagues estimate that over recent decades the continent’s ice shelves lost about 843bn tonnes of mass every year from melting underneath.
That is the equivalent of 843 giant ice cubes – each a kilometre long, wide and deep – all melting. It is about the same amount of water that flows from the Nile River into the ocean each year.
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At the ocean surface, seawater freezes at about -1.9C but under an ice shelf where the water can be a kilometre or more down, the pressure means the ocean water doesn’t freeze until about -2.2C. “The coldest water anywhere in the ocean is beneath the Antarctic ice shelves. There is no light,” says Dr Steve Rintoul, an oceanographer and leading Antarctic expert at the Australian government’s science agency, the CSIRO. “All our conventional tools to measure the ocean can’t reach it,” he says. “Satellites can’t reach it because it’s covered in ice. Ships can’t get in. The shelves are surrounded by heavy sea ice and they’re often heavily crevassed on the surface. Even if you could drill a hole, it’s challenging to get people there.”
Only a handful of holes have been drilled and they can only provide data on what conditions look like in one place amid a vast undersea freezing landscape. But Rintoul’s team got lucky. Scientists use autonomous floating instruments known as Argo floats to measure ocean temperatures and salinity around the world. Rintoul and colleagues deployed one underneath the Totten ice shelf but it drifted away, spending nine months instead under two other ice shelves more than 300 metres thick. The float’s data showed that one of those shelves – the Denman – was being exposed to warm water that was melting it from below. Rintoul says the Denman catchment holds enough water to cause 1.5 metres of global sea level rise.
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https://www.theguardian.com/world/2026/jan/17/climate-antarctica-ice-sheets-glaciers-melting-research-affect-sea-levels