Amazing though it might seem to those roasted in the recent South Australian and NSW heat waves, yet another flotilla of icebergs is making good speed toward the south-eastern tip of New Zealand’s South Island.

At least 130 icebergs, some more than several kilometres long, may be visible from the hills or even the beaches on the Otago coastline near Dunedin by the end of the week, according to NZ government oceanographer Dr Mike Williams.

091125_icebergTabular iceberg passes Macquarie Island

The bergs, remnants of a several huge tabular or flat-topped bergs that broke off the Antarctic ice shelves between 2000 and 2002, have already passed Macquarie Island, where some came close to its shores earlier this month.

They are being tracked by Australia’s Antarctic Climate and Ecosystems CRC in Hobart, which has posted detailed maps of the berg cluster down to less than 200 metres across above the water, or to the limit of satellite resolution.

091125_iceberg map

However, as the bergs further disintegrate, they spawn multitudes of satellite-invisible bergs, some more than 10 metres across, which are very hazardous to shipping and have led to maritime iceberg warnings for the parts of the Southern Ocean where they are rarely seen.

This time the icebergs are expected by NZ authorities to exceed the spectacle caused in 2006 when the first mainland sightings since 1931 were recorded from high hills near Dunedin.

The November 2006 bergs lined the horizon and resolved into an armada of icy towers through binoculars or in close-up to those on chartered sightseeing flights.

Auckland University polar scientist Dr Paul Augustinus says the berg outbreaks are unlikely to be related to global warming.

“I wouldn’t like to speculate on the cause,” he says “it could relate to a number of factors such as the break-up of a larger iceberg.”

And meteorologists say the bergs have been helped in their long voyage north by very cold weather and strong winds affecting the Southern Ocean from Macquarie Island to New Zealand in recent weeks.

Dr Neal Young, a glaciologist with the Australian Antarctic Division, said more than 100 icebergs had been detected in just one cluster in satellite images, but because of extensive cloud cover in the area the real number was uncertain.

“All of these have come from a larger one that was probably close to 20 square kilometres in size when it left Antarctica,” he says.

The Australian Antarctic Division has posted a lay person’s guide to the truth about ice losses and gains in Antarctica, which identifies small net contributions to sea level in recent times.

It’s a document likely to disappoint climate-change deniers and proponents alike, in that it doesn’t support any of the headline-grabbing claims made either side of the populist debate.