Radar image showing the ice-shelf edge of the Thwaites glacier in West Antarctica (thick black line) and the position of the "grounding line" - where ice meets ocean and goes afloat - under a high warming scenario (red line). Source: Joughin et al,. (2014) | Eye-catching words like "collapse", "irreversible", "unstoppable" and "catastrophic" peppered media coverage last week of two papers charting the demise of West Antarctic glaciers.
The first paper in Science looked at how changes in wind and ocean circulations are bringing warm water in contact with the underside of the Thwaites glacier - one of the biggest in West Antarctica - melting it from the bottom up. Similar things are happening with other glaciers across West Antarctica, explained the second paper in Geophysical Research Letters.
Not only are the glaciers shrinking, but there's nothing to stop them melting completely. That's why scientists are talking about the glaciers' collapse as "irreversible" and "unstoppable".
And without the huge glaciers to prop up the interior of the ice sheet, much larger areas of West Antarctic ice will start slipping into the ocean. This would ultimately raise sea levels by three to four metres, though that would take several centuries, say the scientists.
Here are some key questions on both bits of research answered by experts. |