杏吧原创

The fastest-flowing glacier in Antarctica has unexpectedly stopped thinning at its end while a neighbouring glacier continues to lose ice apace, new analysis of satellite data shows.

Pine Island glacier and Thwaites glacier in West Antarctica have been losing ice rapidly and in the long-term could collectively make a huge contribution to sea level rise. However, a UK team was surprised to find that, in the past six years, Pine Island glacier has virtually paused thinning at its terminus, while Thwaites has carried on.

The thinning of the glaciers was tracked using airborne lasers and two satellites. Between 2013 and 2019, there was a decrease of 74 per cent in the rate of loss of elevation at the end of Pine Island glacier, compared with 2000-2010. Thinning has reduced along the length of the glacier too, but at a slower rate.

Andrew Shepherd at the University of Leeds, UK, says: 鈥淭hinning at the terminus of Pine Island glacier actually paused, which is quite a surprise and has made people wonder why. It could be something to do with the ocean in front, or the glacier could be pinned on a rough patch of rock.鈥�

Deadly glacier

In猫s Otosaka, also at the University of Leeds, says one possible explanation is colder ocean water in Pine Island Bay in 2011 and 2013.

The terminus at neighbouring Thwaites saw its rate of elevation loss increase by 58 per cent between 2013 and 2019. Thwaites has been dubbed the world鈥檚 most deadly glacier because it has a key role in supporting the whole of the West Antarctic ice sheet, the loss of which would lead to severe sea level rises.

Otosaka says the pause at Pine Island glacier鈥檚 terminus is no cause for celebration, as overall there is still thinning elsewhere on the glacier. 鈥淭he thinning has stabilised [at that part], but Pine Island glacier still remains one of the largest contributors to sea level rise, so I鈥檓 not sure it鈥檚 very good news.鈥�

The research comes as the second year of a major UK-US field research project gets under way at Thwaites glacier.