scientists predict mini ice age for europe

New northern ice age could send refugees to Aust
By Ashley Hall

Posted Fri Oct 5, 2007 6:26pm AEST
Updated Fri Oct 5, 2007 7:00pm AEST


A new study from the Australian National University (ANU) has found that this country may not be as severely affected by a new ice age as countries in the Northern Hemisphere.

ANU paleoclimatologist Timothy Barrows and his fellow researchers used a new dating technique that measures the radioactive elements in some rocks.

Dr Barrows explains that Europe is at risk of a new ice age as a result of global warming.

"There are some fears that warming in the Northern Hemisphere, particularly around the Greenland ice sheet, might cause quite a bit of meltwater to come into the North Atlantic Ocean," he said.

"That might change the salinity of the water there and stop what's called 'the great conveyor belt of the oceans' forming deep water that releases an enormous amount of heat that keeps Europe out of an ice age, essentially.

"So if global warming does stop this circulation from occurring, then we could potentially have a new ice age in Europe."

Dr Barrows says this effect is similar to what happened about 12,900 years ago, when the earth experienced rapid cooling.

"There was a collapse of an ice sheet over North America, which slowed this circulation down, and caused a mini ice age for 1,500 years in Europe," he said.

He says a new ice age in the Northern Hemisphere is not far off.

"You'd begin to feel the effects almost immediately and certainly within a century," he said.


Bipolar seesaw

But Dr Barrows says the ANU research, published in the journal Science, suggests Australia may be somewhat immune from this coming ice age.

"It was believed that this particular climatic event was global, that it affected all parts of the world, and certainly some research in New Zealand supported that," he said.

"There was a paper several years ago on dating the Franz Josef Glacier. It expanded in the South Island of New Zealand, and that's certainly placed that ice expanse at about that time.

"However, we've now come along and used a different dating technique on that site and found that it actually occurs after the cooling event."

He says that finding lends support to a theory that heat will accumulate in the Southern Hemisphere if there is cooling in the north.

"In conjunction with looking at a deep-sea core off the coast nearby, [it means] that it actually warmed during the period when it was cooling in the Northern Hemisphere, and that supports a theory called the bipolar seesaw, which has to do with where heat goes on the planet when the conveyor belt is operating or not operating," he said.

"So heat tends to accumulate in the Southern Hemisphere if the conveyor belt is not operating."

Dr Barrows says Australia and New Zealand could then become the destination for Europeans fleeing the cold.

"If this was to occur, there would be a large number of refugees from Europe seeking a warmer place to go," he said.


Climate change not globally uniform

He says the findings demonstrate that global climate change will not necessarily happen in a uniform way.

"We get a lot of regionalisation and it depends on what's causing the climate change," he said.

"Certainly on the scale of thousands of years, we see the different parts of the planet can be affected to different degrees.

"So it's important to be able to discover these processes so that we can better plan for the future."

Dr Barrows says the major changes in the world's climate that happened thousands of years ago occurred without human causation and over a long period. In contrast, the current human-caused changes in the climate are occurring on a much shorter timeframe.

"Certainly on the scale of tens of thousands of years, our climate is controlled by the way our planet orbits around the sun and where the sun hits us on the earth," he said.

"On the scale of thousands of years superimposed on top of that is effects like we see with the conveyor belt where we get heat being redistributed across the planet.

"But certainly on the scale of 100 years or 10 years, if we're putting so much CO2 into the atmosphere, that completely overrides these longer natural processes."

Dave R.