Daily updated news @ www.planetearth.nerc.ac.uk NEWS A seismic survey on Pine Island Glacier. in brief . . .


Ash cloud experts must work more closely with civil aviation Weather experts, volcanologists, ash cloud modellers and civil aviation authorities need to work more closely together if they are to get better at forecasting how ash clouds are likely to spread. That’s the conclusion 52 researchers from 12


countries reached after a workshop on how to avoid a repeat of the 2010 Eyjafjallajökull debacle. The workshop aimed to find out the needs of


the ash-dispersal modelling community, look into new ways of collecting data and work out how to improve communication between scientists and civil aviation authorities. They say getting better at assessing uncertainties is an urgent requirement.


Major Antarctic glacier melting speeds up


O


ne of Antarctica’s largest glaciers is melting more than 50 per cent faster than it was just over 15 years ago, a major study has revealed.


The research found that in 1994, the ice shelf that floats on the ocean in front of


Pine Island Glacier in West Antarctica was already melting into the sea at a rate of just over 50 cubic kilometres per year. But by 2009, that rate had risen to a worrying 80 cubic kilometres of ice a year. Some scientists predict that if Pine Island Glacier melted entirely, it could raise


sea levels by around 25cm. The researchers behind the latest study, published in Nature Geoscience,


say that while some of the melting they detected can be blamed on rising sea temperatures, the real problem is that more warm water is reaching a cavity beneath the ice shelf. This is making the ice shelf much more vulnerable to melting. ‘The rate at which the ice shelf is melting has increased significantly, because


more warm water is circulating in the cavity beneath it,’ explains Dr Adrian Jenkins from the British Antarctic Survey (BAS), one of the study’s co-authors. The study revealed that the ocean temperature in Pine Island Bay has gone up


by just 0.2° Celsius over the same period. ‘This isn’t enough to account for the increased melting,’ says Jenkins. It wasn’t until the scientists sent an autonomous submarine, dubbed Autosub,


underneath the ice shelf that they realised why it’s melting so quickly. The sub, built and operated by the National Oceanography Centre, revealed an


underwater ridge on the sea floor beneath the ice shelf. Jenkins and colleagues from BAS and Columbia University concluded that the ridge must have once slowed the glacier like a giant retaining wall. But as soon as the receding glacier broke free from the ridge, at some point


before the 1970s, warmer water could get to the ice shelf’s ‘underbelly’. This would have made the cavity grow, allowing more warm water to flow in and meltwater to flow out, making the glacier accelerate towards the sea. ‘The inner cavity didn’t exist at all before, so this is the most likely explanation for why a subtle change in temperature can have a huge effect,’ Jenkins says.


Scientists prepare to map Scottish seabed Scientists are preparing to create a 3D image of the seabed off the north coast of Scotland to identify marine habitats of high conservation value. They’ve settled on two regions: one could


be important for minke whales; the other may be home to the largest bed of horse mussels in Scottish waters. The researchers, including scientists from the British Geological Survey, plan to use acoustic multi-beam survey techniques. ‘These surveys will help us meet our


international commitments to designate a network of marine-protected areas in Scottish waters,’ says Laura Clark from Scottish National Heritage.


Arctic sea-ice information service in development European scientists are set to work together to establish a sea-ice information service for ships sailing through the Arctic Ocean in summer. The service will provide accurate, up-to-date


information on ice conditions in the region, including the probable location and movements of icebergs. The €2m project, which British Antarctic


Survey remote-sensing expert Andrew Fleming is helping with, is part of Europe’s Global Monitoring system for Environment and Security (GMES). The service should help ships sailing from Europe to China through the Arctic Ocean cut their journey by some 6000km.


PLANET EARTH Autumn 2011 29


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