Scientists conclude that global warming is a natural phenomenon
 

North Pole 'was once subtropical'

An international scientific team which has been drilling beneath the bed of the Arctic Ocean says it enjoyed a sub-tropical climate 55 million years ago.

The Arctic Coring Expedition (Acex) has recovered sediment cores from nearly 400m (1,300ft) below the sea floor.

It says fossilised algae in the cores show the sea temperature was once about 20C (68F), instead of the average now, -1.5C (29.3F).

The expedition, which has relied on three icebreakers during its work, is now heading back to Tromso in Norway.

The cores they have extracted show the Arctic Ocean was once a subtropical, shallow sea. The evidence, Acex says, is in the form of tiny algal fossils found in the cores, which were once marine plants and animals.

They date back to a period known as the Palaeocene-Eocene thermal maximum, a brief period that occurred around 55m years ago.

It was characterized by an extremely warm climate that created a natural greenhouse effect, which caused massive amounts of carbon to be deposited in both sea and air.

The algae found in the Lomonosov cores, which lived only in subtropical conditions, prove how warm the Arctic once was, Acex says. It says the ocean's temperature was once similar to the waters off New York in August.

http://news.bbc.co.uk/1/hi/sci/tech/3631764.stm