Warm Ocean Currents Cause Antarctica Ice Loss26/04/2012
|Reporting in the journal Nature, an international team of scientists led by British Antarctic Survey (BAS) has established that warm ocean currents are the dominant cause of recent ice loss from Antarctica. For the first time, new techniques have been able to differentiate between the two known causes of melting ice shelves: warm ocean currents attacking the underside, and warm air melting them from above. This finding brings scientists a step closer to providing reliable projections of future sea-level rise.|
Researchers used 4.5 million measurements made by a laser instrument mounted on NASA’s ICESat satellite to map the changing thickness of almost all the floating ice shelves around Antarctica, revealing the pattern of ice-shelf melt across the continent. Of the 54 ice shelves mapped, 20 are being melted by warm ocean currents, most of which are in West Antarctica.
Lead author Dr Hamish Pritchard from British Antarctic Survey, which is part of the UK’s Natural Environment Research Council (NERC), said to see a pattern that in all the cases where ice shelves are being melted by the ocean, the inland glaciers are speeding up. It’s this glacier acceleration that’s responsible for most of the increase in ice loss from the continent and this is contributing to sea-level rise. Some ice shelves are thinning by a few metres a year and, in response, the glaciers drain billions of tons of ice into the sea. This supports the idea that ice shelves are important in slowing down the glaciers that feed them, controlling the loss of ice from the Antarctic ice sheet.
He adds the researchers think that it’s linked to changes in wind patterns. Studies have shown that Antarctic winds have changed because of changes in climate and that this has affected the strength and direction of ocean currents. As a result warm water is funnelled beneath the floating ice. These studies and our new results therefore suggest that Antarctica’s glaciers are responding rapidly to a changing climate.
A different picture is seen on the eastern Antarctic Peninsula (the long stretch of land pointing towards South America). Here, the ice-shelf thinning found by this study can be explained by warm summer winds directly melting the snow on the ice-shelf surfaces. Both patterns, of widespread ocean-driven melting and this summer melting on the Antarctic Peninsula, can therefore be attributed to Antarctica’s changing wind patterns.
This research is part of international efforts to improve understanding of the interactions between ice and climate in order to improve the reliability of sea-level rise projections.
Read more about:
Supplier: British Antarctic Survey
More news from this supplier:
Real-time Risk Index For Satellite Operators
Antarctic Geological Timeline Aids Future Sea-Level Predictions
Glacier Subject of Study Sea-level Rise
BAS Antarctic Survey Underway
Massive Subsea Volcanic Peaks and Craters
Marine Cable Route Survey Contract for Swedish National Grid
Optech Showcases Airborne Terrain and Bathymetry Sensors
Marine Milestone for England's Marine Spatial Planning
Tsunami Monitoring System Successfully Completes Trial Observation
New Office For 2G Robotics
Update Shapefile Worldwide Exclusive Economic Zones (EEZ)
Robert J. Walker Wreck Listed as Historic Place
Commercially Exportable IMU-KVH1750 Added to SPAN Line
Airborne Terrain and Bathymetry Sensors at GEOINT
Collaboration Leads to Magnetometer Solution
comments powered by Disqus
Spill Response Baseline Survey
CSIRO from Australia is undertaking a survey tour towards the Australian Bight for a baseline survey looking for oil traces in the water. The surveyors are deploying a CTD and a gravity corer measuring possible traces of oil in the water column. The survey mission also consists of hydrographic mapping techniques, GIS and environmental specialists to make sure the situation before exploration is mapped well in order to know what the environmental consequences of an eventual oil seepage or leak may consist of.