Arctic sea ice has reached its lowest ever recorded level following record summer melting, scientists say.
The extent of the ice at the end of the annual melt has dropped to 3.41 million square kilometres (1.32 million square miles), just over half the minimum area covered on average between 1979 and 2000.
The National Snow and Ice Data Centre in the US said the minimum extent of the sea ice this year shatters the previous all-time low set in September 2007 by 760,000 square kilometres (293,000 square miles), an area the size of Texas.
This year has seen the largest annual melt since the satellite records began in 1979, with 11.83 million square kilometres (4.57 million square miles) of ice melting since March.
While ice cover is now expected to increase as winter comes, a shift in wind patterns or a period of late season melt could see levels fall further, the NSIDC said.
The new record low reinforces the long-term downward trend in the extent of the Arctic sea ice, the scientists said.
NSIDC director Mark Serreze said: "We are now in uncharted territory.
"While we've long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur."
The researchers said summer temperatures across the Arctic were warmer than average, but cooler than the previous record-breaking year of 2007.
But the ice cover has continued to thin and become dominated by seasonal ice, which has only frozen over during the winter.