Qtec
06-09-2004, 07:36 PM
http://news.bbc.co.uk/2/hi/science/nature/3792209.stm
Ice cores unlock climate secrets
By Julianna Kettlewell
BBC News Online science staff
Global climate patterns stretching back 740,000 years have been confirmed by a three-kilometre-long ice core drilled from the Antarctic, Nature reports.
Analysis of the ice proves our planet has had eight ice ages during that period, punctuated by rather brief warm spells - one of which we enjoy today.
If past patterns are followed in the future, we can expect our "mild snap" to last another 15,000 years.
The data may also help predict how greenhouse gases will affect climate.
Initial tests on gas trapped in the ice core show that current carbon dioxide (CO2) levels are higher than they have been in 440,000 years.
Another important thing that scientists can 'read' in the ice is the relative concentration of atmospheric gases.
That is because minute bubbles pock mark the core, within which tiny pockets of preserved air lie.
"That is the wonderful thing about ice cores," said Professor McManus. "There is air from three-quarters of a million years ago and it is still locked in these bubbles - it's incredible."
Turning which way?
Epica is still busy analysing the ice core's atmospheric gases, but preliminary results suggest that present CO2 levels are remarkably high.
"We have never seen greenhouse gases anything like what we have seen today," said Dr Wolff.
Q
Ice cores unlock climate secrets
By Julianna Kettlewell
BBC News Online science staff
Global climate patterns stretching back 740,000 years have been confirmed by a three-kilometre-long ice core drilled from the Antarctic, Nature reports.
Analysis of the ice proves our planet has had eight ice ages during that period, punctuated by rather brief warm spells - one of which we enjoy today.
If past patterns are followed in the future, we can expect our "mild snap" to last another 15,000 years.
The data may also help predict how greenhouse gases will affect climate.
Initial tests on gas trapped in the ice core show that current carbon dioxide (CO2) levels are higher than they have been in 440,000 years.
Another important thing that scientists can 'read' in the ice is the relative concentration of atmospheric gases.
That is because minute bubbles pock mark the core, within which tiny pockets of preserved air lie.
"That is the wonderful thing about ice cores," said Professor McManus. "There is air from three-quarters of a million years ago and it is still locked in these bubbles - it's incredible."
Turning which way?
Epica is still busy analysing the ice core's atmospheric gases, but preliminary results suggest that present CO2 levels are remarkably high.
"We have never seen greenhouse gases anything like what we have seen today," said Dr Wolff.
Q