Mobile phones and seals help to uncover why a glacier is melting
By Mark Viney
We’re all tied to our mobile phones 24/7, but scientists are now getting daily text messages from Antarctica’s Pine Island Glacier which they use to track the glacier’s daily movements.
The planet’s oceans are rising an average of about 3 mm each year, largely as a result of melting glaciers, and the Pine Island Glacier, which makes up approximately 10% of the West Antarctic Ice Sheet, is making the biggest single contribution of a glacier to sea level rise, probably 0.1-0.25 mm each year. The glacier covers more than 150,000 km2, about two thirds the size of the UK, and is 2 km thick, although it is thinning by about 1 metre a year.
The speed at which the Pine Island Glacier is changing has surprised scientists. A new research programme – iSTAR – launched today will investigate why the glacier is shrinking so fast, and inform better predictions about future rises in sea levels.
iSTAR is a £7.4 million research programme of 35 scientists funded by the Natural Environment Research Council. Professor Mick Bentley of the University of Durham, and one of iSTAR’s leaders told the British Science Festival today that this study “will for the first time co-ordinate measurements using different methods”. iSTAR will use ships, tractors, planes and satellites to deploy newly developed technologies and techniques, including glacier text messaging.
Some parts of the glacier are too dangerous for scientists to visit, so instead 2 metre tall rocket-shaped GPS mobile phones will be dropped from planes. When they hit the glacier the sensors pierce the glacier’s surface, but leave a protruding transmitter tail above the snow and ice. Each day these “ADIOS” (Aircraft Deployable Ice Observation System) devices will send a text message of their precise position back to the UK. With information from 20 ADIOS devices the scientists will be able to precisely measure the average 10 metre daily movement of the glacier.
As well as measuring how the glacier is moving, iSTAR will also investigate how the ocean moves warmer water beneath the glacier, a process that accelerates its melting. Autonomous submarines will be used to measure temperature and saltiness under the glacier. But these machines can only be used in the Antarctic summer. In the winter, the Antarctic Ocean is no place for man-made machines, so instead iSTAR will turn to something much tougher – seals.
Seals will be fitted with small sensors which will record the depth, sea temperature and salinity as the seals dive. For one year, each time a seal surfaces to breath, the data taken from the dive will be transmitted to satellites. The submarine and seals combined will provide one of the best-ever understandings of how water flows under the glacier and of the rate at which the glacier is melting, and this information will help scientists predict potential future rises in sea levels.