The area covered by sea ice in the Arctic has shrunk for a fourth consecutive year, according to new data released by US scientists.
They say that this month sees the lowest extent of ice cover for more than a century.
The Arctic climate varies naturally, but the researchers conclude that human-induced global warming is at least partially responsible.
They warn the shrinkage could lead to even faster melting in coming years.
...September is the month when the Arctic ice usually reaches a minimum.
The new data shows that on 19 September, the area covered by ice fell to 5.35 million sq km (2.01 million sq miles), the lowest recorded since 1978, when satellite records became available; it is now 20% less than the 1978-2000 average.
The current rate of shrinkage they calculate at 8% per decade; at this rate there may be no ice at all during the summer of 2060.