Dr Funder and his team say their data shows a clear connection between temperature and the amount of sea ice. 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.”