Massive iceberg breaks in Antarctica

In this satellite image released by Commonwealth of Australia, a 97km long iceberg known as B9B, right, crashes into the Mertz Glacier Tongue, left, in the Australian Antarctic Territory on February 20, 2010. The collision created a new 78km long iceberg. (AP Photo/Commonwealth of Australia)

A big chunk of ice, slightly smaller than the Hawaiin island of Oahu, broke off from a place it wasn't supposed to and in a way that wasn't quite anticipated, scientists reported today.

The new iceberg broke off from the cooler eastern end of Antarctica, the result of tidal forces that caused a longer but thinner iceberg that stretches for 90km to hammer it free. The new chunk broke off a long tongue of ice that had been building for decades, but will unlikely cause future ice loss problems on the continent, scientists said.

This happened as researchers have focused attention on the western side of Antactica, a continent about 1 1/2 times larger than the United States. Concern has grown over warmer temperatures there and especially the region's shrinking peninsula, which sticks out into the water like a broken finger.

Remarkably, that peninsula, where last year one ice shelf was said to be hanging by a thread, has had an unusually cool summer. It's hit pause on ice loss, said Ted Scambos, senior scientist with the National Snow and Ice Data Center.

In a satellite phone interview this week from the western peninsula where he's working, Scambos predicted no major ice calving.

The next day Australian researchers alerted the world to the iceberg crash with the Mertz Glacier on the other side of the continent. They said it had probably occurred around February 12 or 13.

"There are some crazy things going down in Antarctica," said Mark Serreze, director of the snow and ice data centre, based in Boulder, Colorado. "It seems kind of weird, but weird things happen."

Scientists have been tracking global warming's influence in Antarctica, a place more complicated than the Arctic. Scambos was placing instruments on the dwindling Larsen ice shelf in the peninsula to measure its disintegration in a scientific version of a deathwatch.

The ice loss that happened a couple of weeks ago was not due to global warming, but a natural process taking place in a region that has been relatively stable over the years.

For decades the tongue of the Mertz Glacier in the eastern part of the continent has grown further out into the water until it was about 90km long by 30km wide, said Benoit Legresy, a researcher with the LEGOS laboratory for geophysical studies in Toulouse, France.

Then an iceberg called B9B, which had broken off from another part of Antarctica in 1987, came by and "gave it a pretty big nudge," said Australian Antarctic Division glaciologist Neal Young.