Arctic 'tipping point' may not be reached

The researchers concluded that for about 3,000 years, during a period called the Holocene Climate Optimum, there was more open water and far less ice than today - probably less than 50% of the minimum Arctic sea ice recorded in 2007.

But the researcher says that even with a loss of this size, the sea ice will not reach a point of no return.

"I think we can say that with the loss of 50% of the current ice, the tipping point wasn't reached."

The idea of an Arctic tipping point has been highlighted by many scientists in recent years. They have argued that when enough ice is lost it could cause a runaway effect with disastrous consequences.