Giant Antarctic iceberg heads towards N.Zealand: experts

A giant iceberg twice the length of Beijing's "Bird's Nest" Stadium has been spotted floating off Australia and could be headed for New Zealand, scientists said on Thursday.

The ice chunk, measuring some 700 metres (2,300 feet) long with an estimated depth of 350 metres, caused a stir when it was sighted by experts based on Australia's remote Macquarie Island.

"I've never seen anything like it -- we looked out to the horizon and just saw this huge floating island of ice," said fur seal biologist Dean Miller.

Australian Antarctic Division glaciologist Neal Young said the flat-topped slab could break into dozens of smaller icebergs as it moves in the direction ofNew Zealand, causing a possible shipping hazard.

"It's rare to make a sighting like this -- it's certainly impressive-looking," Young told AFP.

He said the iceberg had probably split from a major Antarctic ice shelf nine years ago, and said more could be expected in the area if global warmingcontinues.

"If the current trends in global warming were to continue I would anticipate seeing more icebergs and the large ice shelves breaking up," he added.

November 12, 2009 

(c) 2009 AFP

Greenland ice cap melting faster than ever

Satellite observations and a state-of-the art regional atmospheric model have independently confirmed that the Greenland ice sheet is loosing mass at an accelerating rate, reports a new study in Science.

This mass loss is equally distributed between increased iceberg production, driven by acceleration of Greenland's fast-flowing outlet glaciers, and increased meltwater production at the ice sheet surface. Recent warm summers further accelerated the mass loss to 273 Gt per year (1 Gt is the mass of 1 cubic kilometre of water), in the period 2006-2008, which represents 0.75 mm of global sea level rise per year.

Professor Jonathan Bamber from the University of Bristol and an author on the paper said: "It is clear from these results that mass loss from Greenland has been accelerating since the late 1990s and the underlying causes suggest this trend is likely to continue in the near future. We have produced agreement between two totally independent estimates, giving us a lot of confidence in the numbers and our inferences about the processes".

The Greenland ice sheet contains enough water to cause a global sea level rise of seven metres. Since 2000, the ice sheet has lost about 1500 Gt in total, representing on average a global sea level rise of about half a millimetre per year, or 5 mm since 2000.

At the same time that surface melting started to increase around 1996, snowfall on the ice sheet also increased at approximately the same rate, masking surface mass losses for nearly a decade. Moreover, a significant part of the additional meltwater refroze in the cold snowpack that covers the ice sheet. Without these moderating effects, post-1996 Greenland mass loss would have been double the amount of mass loss observed now.

Source: University of Bristol (news : web)

From PhysOrg.com 

November 12, 2009