One study maps how iceberg calving – the breaking off of ice from a glacier front – has changed the Antarctic coastline over the last 25 years.
The researchers found that the edge of the ice sheet has been shedding icebergs faster than the ice can be replaced. The finding doubles previous estimates of ice loss from Antarctic’s floating ice shelves since 1997, from 6 trillion to 12 trillion tonnes.
Ice loss from calving has weakened the ice shelves and allowed Antarctic glaciers to flow more rapidly to the ocean, accelerating the rate of global sea level rise.
The other study shows in unprecedented detail how the Antarctic ice is thinning as ocean water melts it. The thinning 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.
“Antarctica is crumbling at its edges,” said scientist Chad Greene, lead author of the calving study. “And when ice shelves dwindle and weaken...