... but the globe keeps warming

DOES last week's Arctic weather show that global warming - whose existence was confirmed by more than 2,000 of the world's top scientists only this month - is not taking place after all?

The answer is no. Indeed, it may even be a harbinger of things to come in Britain, if the world warms up. Some leading scientists fear that global warming may paradoxically make Britain and other parts of northern Europe much colder.

In the first place, a week or two of unusually cold - or unusually warm - weather in a particular part of the world cannot realistically be cited in evidence either for or against climate change. The weather is changing all the time: what scientists look for are long-term trends in the world's climate averaged over the planet as a whole.

Last week's disclosure that 1995 has been the warmest year ever recorded worldwide - as the Independent on Sunday predicted over a year ago - is yet more reliable evidence. But its real significance is that it is just one of a chain of record-breaking warm years that occurred in the late 1980s and 1990s.

This sequence - and the fact that over the last century average world temperatures have risen by 0.5 degrees Centigrade - is the foundation of the increasing belief of the Intergovernmental Panel on Climate Change (IPCC), the official body of over 2,000 scientists set up by the world's governments to monitor the state of the climate, that global warming is indeed taking place.

The IPCC this month also raised the possibility that global warming might weaken the Gulf Stream, which keeps Britain and northern Europe relatively warm. The Gulf Stream imparts as much heat to Britain as the sun. A glance at the map shows what our climate might be like without it: we are on the same latitude as Labrador.

The IPCC cites ominous evidence that the warming of the world's climate is already affecting the pattern of currents in the North Atlantic. If this is indeed happening, last week's weather could be a foretaste of the future.