Scientists say they have been able to prove for the first time that human activity is contributing to the warming of both the Arctic and Antarctic.

British researchers say their analysis shows that increasing temperatures cannot be explained by natural causes alone.

The researchers say that they expected this result for the Arctic because of the recent sharp increase in the summer melting of sea ice in the region.

But temperature variations in the Antarctic have until now been harder to interpret.

Today's study however indicates that there is a clear human influence there too.

Last year, the Intergovernmental Panel on Climate Change (IPCC) presented strong scientific evidence that a recent rise in average global temperature is mostly due to human activities.

At the time there was not enough evidence for the panel to formally say this about the Arctic and Antarctic.

That gap, the researchers say, has now been plugged.

- BBC