600 year old warming in Antarctic

2012-08-23 09:28
Polar regions have had extremely warm periods, researchers have found. (AP)

Polar regions have had extremely warm periods, researchers have found. (AP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories


VIDEO: Climate and ocean link

2012-08-17 08:35

Jacqueline McGlade, the executive director of the European Environment Agency discusses the connection between climate and ocean in this YouTube video.WATCH

Oslo - Temperatures in the Antarctic Peninsula started rising naturally 600 years ago, long before man-made climate changes further increased them, scientists said in a study on Wednesday that helps explain the recent collapses of vast ice shelves.

The study, reconstructing ancient temperatures to understand a region that is warming faster than anywhere else in the southern hemisphere, said a current warming rate of 2.6°C per century was "unusual" but not unprecedented.

"By the time the unusual recent warming began, the Antarctic Peninsula ice shelves were already poised for the dramatic break-ups observed from the 1990s onward," said the British Antarctic Survey, which led the study published in the journal Nature.

A warming trend caused by natural variations, perhaps affecting winds and ocean currents, began 600 years ago and made ice shelves - tracts of ice floating on the ocean around the peninsula - vulnerable to even faster warming since 1920.

Several ice shelves around the peninsula have collapsed in recent years, including the Larsen A and B shelves and the Wilkins. About 25 000km² of ice has been lost, roughly the size of Haiti.

Sea levels

Burning of fossil fuels since the Industrial Revolution in the 18th century has emitted heat-trapping greenhouse gases, raising temperatures and causing floods, droughts and rising sea levels as ice melts, according to a UN panel of scientists.

"What we are seeing is consistent with a human-induced warming, on top of a natural one," said Robert Mulvaney, lead author at the British Antarctic Survey. He cautioned that the study, conducted with experts in Australia and France, only referred to one small part of Antarctica.

The scientists dug a core of ice, with year-by-year clues to temperatures, 364m deep on James Ross Island at the north of the peninsula to examine records back 15 000 years.

The loss of floating ice shelves does not itself raise sea levels because the water is already part of the ocean. But glaciers on land can start sliding faster toward the sea and add water when shelves holding them back vanish.

Glaciers on the peninsula are small by the standards of Antarctica, which contains enough ice to raise world sea levels by about 60m if it ever all melted. Even a small thaw would threaten low-lying nations and cities.

"If this rapid warming that we are now seeing continues, we can expect that ice shelves further south along the peninsula that have been stable for thousands of years will also become vulnerable," said Nerilie Abram, of the Australian National University.

The scientists said temperatures on the peninsula had been slightly higher than now about 11 000 years ago near the end of the last Ice Age, and some ice shelves retreated. A long cooling period ended around 600 years ago.

Himalayan glaciers

Separately in Nature, researchers monitoring Himalayan glaciers said that they had found evidence of a slight overall thaw in recent years - slightly more of a melt than in another recent study - in what they said was the most detailed overview of the world's highest mountain range.

Glaciers feed rivers such as the Ganges, the Mekong and the Yangtze and their flows are vital for food production.

The UN panel of climate scientists had to correct a 2007 report about the impacts of climate change after wrongly projecting that all Himalayan glaciers might melt by 2035 - far faster than scientists project.

"There is no runaway melt. Most of the glaciers are melting at a similar rate to other glaciers in the world," said lead author Andreas Kaab at the University of Oslo of the study of glaciers in the Hindu Kush, Karakoram and Himalayas.
Read more on:    climate change

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

linking and moving

2015-04-22 07:36

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
Comments have been closed for this article.

Inside News24


For the love of Corgis!

WATCH: 35 Corgi's to make your day! If they’re good enough for the Queen of England they’re good enough for us.



Can we communicate with our pets?
8 great natural remedies for your pet
Buying a puppy? Don’t get scammed!
WATCH: These funny animal videos will make you LOL!
Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.