Please select your home edition
Edition
Abell Point Marina 728x90 Moor

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

NaiadHarken and Fosters -  Harken WinchesSydney Harbour Boat Storage 660x82

Related Articles

Princess to pay largest ever criminal penalty for vessel pollution
Princess Cruise Lines has agreed to plead guilty to seven felony charges stemming from deliberate pollution of the seas Princess Cruise Lines Ltd. (Princess) has agreed to plead guilty to seven felony charges stemming from its deliberate pollution of the seas and intentional acts to cover it up. Princess will pay a $40 million penalty– the largest-ever criminal penalty involving deliberate vessel pollution – and plead guilty to charges related to illegal dumping of oil contaminated waste from the cruise ship.
Posted on 2 Dec
Race for Water catamaran to be equipped with new hydrogen system
Race for Water will make it possible for the crew to free themselves of the need for fossil fuels during new mission. Race for Water will make it possible for the crew to completely free themselves of the need for fossil fuels during the new mission against the pollution of the oceans.
Posted on 26 Nov
Radio spectrum changes have been put into place in New Zealand
New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels New Zealand, along with a number of other countries, has been required to change some maritime VHF repeater channels to make space for newly allocated international services for ship tracking and data services. On the October 1st, New Zealand moved a few private VHF repeater services, most Coastguard VHF repeater services, and all NowCasting weather services. An updated radio handbook and freq
Posted on 2 Nov
Operation Retune underway in remote corners of New Zealand
Radio technicians have been working at sites for the Maritime VHF channel changes Radio technicians have been working at sites for the Maritime VHF channel changes The scenery is spectacular but getting to transmitters sites in New Zealand can be a challenge for radio technicians working on the Maritime VHF change over.
Posted on 4 Oct
Skies clear for final day of the Auckland On the Water Boat Show
Heavy rain which hit the Auckland On the Water Boat Show has cleared and it is business as usual The heavy rain which hit the Auckland On the Water Boat Show and the rest of the province has cleared and it is business as usual for the final day. The crowds were at the Viaduct Events Centre gat at 10.00am this morning - a little surprising given the heavy rain which has plagued Auckland over night and at Show opening time, plus the All Blacks Test match which started at 11.00am.
Posted on 1 Oct
Auckland On the Water Boat Show - Images from Day3
The Auckland On the Water Boat Show pulled a great crowd again today The Auckland On the Water Boat Show pulled a great crowd again today, with the threatening weather which dogged the last couple of hours of yesterday's Show, being thankfully absent. The Show finished Sunday at 5.00pm - catch some great exhibits - and it is great fun for kids. Don't miss having a look at HMNZS Hawea tied alongside.
Posted on 1 Oct
'The best day of my life' - Auckland On the Boat Show - Day 3
Despite the forecast of dicey weather, visitors to the Auckland On the Water Boat Show were rewarded with a good day Despite a less than optimist forecast of more inclement weather, visitors to the Auckland On the Water Boat Show were rewarded with a good day to be at the Show – overcast skies, but no rain and plenty to see and do. Held for the first time in the school holidays, the kids – who get free entry – had a great day.
Posted on 1 Oct
Auckland on the Water Boat Show - Showers don't deter crowds on Day 2
A tsunami of boating fans of all persuasions swept through the gates of the Auckland On the Water Boat Show this morning A tsunami of boating fans of all persuasions swept through the gates of the Auckland On the Water Boat Show when they opened this morning. Whether it was a result of the morning weather forecast or Friday was just a convenient day - who knows?
Posted on 30 Sep
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