It is not often that positive news comes from Antarctica, especially when it comes to ice. Nonetheless, a team of geologists from Ohio University have discovered that the bedrock of the West Antarctic Ice Sheet is rising at a rapid pace. The researchers describe it as a ‘game changer’ when it comes to ice loss prevention in the region.
Scientists were already aware the West Antarctic ground was rising – it is caused by the bedrock rebounding after ice melt. The main surprise was the rate of the uplift under the Amundsen Sea – a speedy 41 millimetres per year. How does that help preserve ice? The idea is that rising rock creates pointed features that pin the ice sheet in place from underneath – ‘pinning points’ – which slow the ice’s descent to the sea. The researchers also predict that the rising bedrock could decrease the gradient of glacier slopes, further slowing the ice loss. Professor of Earth Science and contributing author, Terry Wilson, explained these feedbacks could ‘slow or even stop’ the process of freshwater ice melting into the sea. ‘Under many realistic climate models, this should be enough to stabilise the ice sheet’.
The rate of uplift is unusually high. It is faster even than Alaska and Iceland, which are considered to have quick rates of uplift of 20 to 30mm per year. The exception is being put down to geology. Valentina Barletta, lead author of the study, believes there is hotter and more fluid mantle under the bedrock, which causes the ground to rise quicker. She predicts the rate will become even faster in time, by around two or three times through the next century.
There is some bad news. The uplift may have disguised how much the ice has already diminished on the West Antarctica Ice Sheet. Specifically, the uplift rates are thought to have confused gravity readings in the region, leading researchers to underestimate the ice loss by ten per cent. The finding is significant given that the sheet accounts for a quarter of the ice contribution to global sea-level rise.
This was published in the August 2018 edition of Geographical magazine
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