![]() But we now have enough data from multiple satellite sensors to see a clear picture of how Antarctica’s coastline has evolved in recent years.”įor the new study, Greene and his colleagues synthesized satellite imagery of the continent in visible, thermal infrared (heat), and radar wavelengths since 1997. ![]() ![]() “For example, you can imagine looking at a satellite image and trying to figure out the difference between a white iceberg, white ice shelf, white sea ice, and even a white cloud,” said Greene. Part of the reason is that satellite imagery has been challenging to interpret. Although satellite altimeters measure the thinning process by recording the changing height of the ice, until this study, there hasn’t been a comprehensive assessment of how climate change might be affecting calving around the continent. However, in recent decades, the warming ocean has been destabilizing Antarctica’s ice shelves by melting them from below, making them thinner and weaker. The missions that supplied data are listed at the bottom. Ice height diminishes (red) as the ice sheet melts by contact with ocean water it rises (blue) where accumulation exceeds melting. When ice shelves are stable, they have a natural cycle of calving and replenishment that maintains their size fairly consistently over the long term.Ĭhanges in elevation of the Antarctic ice sheet from 1985 to 2021 are shown. Ice shelves act like buttresses to glaciers, keeping the ice from simply sliding into the ocean. Most Antarctic glaciers flow to the ocean, where they end in floating ice shelves that are up to 2 miles (3 kilometers) thick and 500 miles (800 kilometers) across. “And when ice shelves dwindle and weaken, the continent’s massive glaciers tend to speed up and increase the rate of global sea level rise.” “Antarctica is crumbling at its edges,” says JPL scientist Chad Greene, lead author of the calving study. Combined, the complementary reports provide the most complete view yet of how the frozen continent is changing. The other study, published recently in the journal Earth System Science Data, shows in unprecedented detail how the thinning of Antarctic ice as ocean water melts it has spread from the continent’s outward edges into its interior, almost doubling in the western parts of the ice sheet over the past decade. Ice loss from calving has weakened the ice shelves, allowing Antarctic glaciers to flow more rapidly to the ocean and accelerating the rate of global sea level rise. This surprising finding doubles previous estimates of ice loss from the Antarctic’s floating ice shelves since 1997, from 6 trillion to 12 trillion metric tons. The scientists found that the edge of the ice sheet has been shedding icebergs faster than the ice can be replaced. The new iceberg – which is about 689 feet thick and weighs some 315 billion tons – will now be tracked because it poses a potential hazard for shipping, CNN said. It's likely to take several years for it to break apart and melt completely, the BBC reported.One study, published recently in the journal Nature, maps how iceberg calving – the breaking off of ice from a glacier front – has changed the Antarctic coastline over the last 25 years. “But what will be interesting to see is how the loss of this ice will influence the ocean melting under the remaining ice shelf and the speed at which the ice flows off the continent.” “The calving will not directly affect sea level because the ice shelf was already floating, much like an ice cube in a glass of water,” Galton-Fenzi said. Here's what that means for the planetīen Galton-Fenzi, a glaciologist with the Australian Antarctic Program, said scientists picked up last week’s calving event by looking at satellite imagery. ![]() 'Polar bears may disappear.' Arctic sea ice keeps shrinking. It’s part of the ice shelf’s normal cycle, where we see major calving events every 60-70 years,” Fricker added. “We don’t think this event is linked to climate change. The last major calving event on the Amery was in 1963-64.
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