Over the past two decades, the massive platforms of floating ice that dot the coast of Antarctica have been thinning and doing so at an increasing rate, likely at least in part because of global warming. Scientists are worried about its implications for significant sea level rise.
The ice shelves—some of which are larger than California and tens to hundreds of yards thick—are the linchpins of the Antarctic ice sheet system, holding back the millions of cubic miles of ice contained in the glaciers that flow into them, like doorstops. As the ice sheets thin, the massive rivers of ice behind them can surge forward into the sea.
Antarctica holds enough ice, if it all melted, to raise sea levels more than 200 feet. That would take hundreds to thousands of years, but the recent thinning of the ice shelves means that there has already been an increase in the rate of Antarctica’s contribution to sea level rise, and it’s accelerating.