Please select your home edition
Edition
InSunSport - International - RG

Antarctic sea ice cover increases under the effects of climate change

by British Antarctic Survey on 16 Nov 2012
Sea ice around Antarctica British Antarctic Survey © http://www.antarctica.ac.uk
The first direct evidence that marked changes to Antarctic sea ice drift have occurred over the last twenty years, in response to changing winds, is published this week in the journal Nature Geoscience. Scientists from NERC’s British Antarctic Survey (BAS) and NASA’s Jet Propulsion Laboratory (JPL), Pasadena California explain why, unlike the dramatic losses reported in the Arctic, the Antarctic sea ice cover has increased under the effects of climate change.

Maps created by JPL using over five million individual daily ice motion measurements captured over a period of 19 years by four US Defense Meteorological satellites show, for the first time, the long-term changes in sea ice drift around Antarctica.

Lead author, Dr. Paul Holland of BAS says: 'Until now these changes in ice drift were only speculated upon, using computer models of Antarctic winds. This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea-ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall. We now know that these regional changes are caused by changes in the winds, which in turn affect the ice cover through changes in both ice drift and air temperature. The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea-ice growth.

'Sea ice is constantly on the move; around Antarctica the ice is blown away from the continent by strong northward winds. Since 1992 this ice drift has changed. In some areas the export of ice away from Antarctica has doubled, while in others it has decreased significantly.'

Sea ice plays a key role in the global environment — reflecting heat from the sun and providing a habitat for marine life. At both poles sea ice cover is at its minimum during late summer. However, during the winter freeze in Antarctica this ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than a metre to several metres, the ice insulates the warm ocean from the frigid atmosphere above.

The new research also helps explain why observed changes in the amount of sea-ice cover are so different in the two Polar Regions. The Arctic has experienced dramatic ice losses in recent decades while the overall ice extent in the Antarctic has increased slightly. However, this small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea-ice cover to expand outwards from Antarctica. The Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way.

Dr. Ron Kwok, JPL says, 'The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent.'

There has been contrasting climate change observed across the Antarctic in recent decades. The Antarctic Peninsula has warmed as much as anywhere in the Southern Hemisphere, while East Antarctica has shown little change or even a small cooling around the coast. The new research improves understanding of present and future climate change. It is important to distinguish between the Antarctic Ice Sheet — glacial ice — which is losing volume, and Antarctic sea ice — frozen seawater — which is expanding.

This research was funded by the Natural Environment Research Council (NERC) and National Aeronautics and Space Administration British Antarctic Survey website

Harken and Fosters -  Harken WinchesInSunSport - NZPantaenius - Worldwide Support

Related Articles

New Zealand Maritime radio channels set to change on 1 October
Before you head out on the water next summer there are some important maritime radio changes you need to know about. Before you head out on the water next summer there are some important maritime radio changes you need to know about. On 1 October 2016, New Zealand is changing some maritime VHF repeater channels, and NowCasting weather services, to make space for new international ship tracking and data services, and to make sure our VHF radio services are compatible with the rest of the world.
Posted on 20 Sep
'Grate Art' in Hong Kong
Hong Kong charity pioneers environmental awareness through innovative storm grate installations In an effort to help Hong Kongers play their part in protecting the world’s ocean, Ocean Recovery Alliance is raising awareness through a unique public art installation called ‘Grate Art’. Hong Kong’s drainage system is one of the main sources for debris outflow into the ocean, and Ocean Recovery Alliance is tackling this problem upstream through an initiative that uses “art for awareness”.
Posted on 14 Sep
Reef sharks take small bites
Coral reef sharks eat prey that are smaller than a cheeseburger Sharks have a reputation for having voracious appetites, but a new study shows that most coral reef sharks eat prey that are smaller than a cheeseburger
Posted on 20 Mar
Suburbs to Sea - Stopping litter at the source
Over sixty people gathered at Point Cook Community Centre for a special ‘Movies and Muffins’ night to learn about litter Over sixty people gathered at Point Cook Community Centre recently for a special ‘Movies and Muffins’ night to learn about litter and its impact on the environment as part of Wyndham City’s Green Living Series.
Posted on 18 Mar
Good radio communication tips - Video
Good communications could make all the difference in an emergency at sea. Here's some great basic communication tips Good communications could make all the difference in an emergency at sea. Here's some great basic communication tips from Scott Walker and Mal Williams from Outdoors Group.
Posted on 10 Mar
We can fix the Great Barrier Reef
Leading coral reef scientists say Australia could restore Great Barrier Reef to its former glory through better policies Leading coral reef scientists say Australia could restore the Great Barrier Reef to its former glory through better policies that focus on science, protection and conservation.
Posted on 20 Feb
Great Barrier Reef marine reserves combat coral disease
A new and significant role for marine reserves on the Great Barrier Reef has been revealed A new and significant role for marine reserves on the Great Barrier Reef has been revealed, with researchers finding the reserves reduce the prevalence of coral diseases.
Posted on 20 Feb
Powerboat noise gives marine predators a deadly advantage
A pioneering new study shows the rate fish are captured by predators can double when boats are motoring nearby. A pioneering new study shows the rate fish are captured by predators can double when boats are motoring nearby.
Posted on 8 Feb
More recreational boaties wearing lifejackets
In good news for boating safety, more recreational boaties are wearing lifejackets the entire time they are on the water In good news for boating safety, more recreational boaties are wearing lifejackets the entire time they are on the water. Maritime New Zealand has released new research into recreational boating behaviour that shows in 2015 78 per cent of recreational boaties reported wearing a lifejacket the entire time they were on the water. This is up from 67 per cent in 2014, and 62 per cent in 2013.
Posted on 13 Jan
Eco-warriors Sea-Bin crowd sharing critical stage with nine days to go
The automated marina cleaning SeaBin project has raised 86% of their target with 9 days left. The automated marina cleaning SeaBin project has raised $198,020 of $230,000.00 with nine days left on their Indiegogo crowdfunding platform, but they need more help now.
Posted on 29 Dec 2015