12 April 2017, Nature, Antarctica’s sleeping ice giant could wake soon. The massive East Antarctic Ice Sheet looks stable from above — but it’s a dangerously different story below. These first direct observations confirmed a fear that researchers had long harboured: that warm waters from the surrounding ocean can sneak underneath the floating glacier tongue and eat the ice away from below1. “This could explain why Totten has been thinning in the past few decades,” says Rintoul. Findings such as these are revealing some scary truths about East Antarctica — the vast, remote landmass to the east of the Transantarctic Mountains (see ‘Ice king’). This region is about as big as the entire United States and the majority of it stands on a high plateau up to 4,093 metres above sea level, where temperatures can plunge to −95 °C. Because the East Antarctic Ice Sheet seems so cold and isolated, researchers thought that it had been stable in the past and was unlikely to change in the future — a stark contrast to the much smaller West Antarctic Ice Sheet, which has raised alarms because many of its glaciers are rapidly retreating. In the past few years, however, “almost everything we thought we knew about East Antarctica has turned out to be wrong”, says Tas van Ommen, a glaciologist at the Australian Antarctic Division in Kingston, near Hobart. By flying across the continent on planes with instruments that probe beneath the ice, his team found that a large fraction of East Antarctica is well below sea level, which makes it more vulnerable to the warming ocean than previously thought. The researchers also uncovered clues that the massive Totten glacier, which holds about as much ice as West Antarctica, has repeatedly shrunk and grown in the past2 — another sign that it could retreat in the future. Read More here
10 April 2017, The Guardian, Great Barrier Reef at ‘terminal stage’: scientists despair at latest coral bleaching data. ‘Last year was bad enough, this is a disaster,’ says one expert as Australia Research Council finds fresh damage across 8,000km. Back-to-back severe bleaching events have affected two-thirds of Australia’s Great Barrier Reef, new aerial surveys have found. The findings have caused alarm among scientists, who say the proximity of the 2016 and 2017 bleaching events is unprecedented for the reef, and will give damaged coral little chance to recover. Australia’s politicians have betrayed the Great Barrier Reef and only the people can save it | David Ritter Scientists with the Australian Research Council’s Centre of Excellence for Coral Reef Studies last week completed aerial surveys of the world’s largest living structure, scoring bleaching at 800 individual coral reefs across 8,000km. The results show the two consecutive mass bleaching events have affected a 1,500km stretch, leaving only the reef’s southern third unscathed.Where last year’s bleaching was concentrated in the reef’s northern third, the 2017 event spread further south, and was most intense in the middle section of the Great Barrier Reef. This year’s mass bleaching, second in severity only to 2016, has occurred even in the absence of an El Niño event. Mass bleaching – a phenomenon caused by global warming-induced rises to sea surface temperatures – has occurred on the reef four times in recorded history. Prof Terry Hughes, who led the surveys, said the length of time coral needed to recover – about 10 years for fast-growing types – raised serious concerns about the increasing frequency of mass bleaching events. “The significance of bleaching this year is that it’s back to back, so there’s been zero time for recovery,” Hughes told the Guardian. “It’s too early yet to tell what the full death toll will be from this year’s bleaching, but clearly it will extend 500km south of last year’s bleaching.” Read more here