As the planet warms up, the home of Father Christmas is becoming the repository of our unwanted pollutants
Santa Claus has little reason to make merry this festive season. For his reindeer are dying, he is increasingly exposed to gender-bending chemicals, and his home is dissolving.

In spring, the North Pole - where St Nicholas is reputed to spend 364 nights of the year - is shrouded in smog and grilled by ultra-violet radiation that penetrates a thinning ozone layer. And as global warming increases in the next century, some scientists predict that the ice will melt altogether in the summer - leaving open ocean.

Long one of the most pristine areas on earth, the Arctic and its people are increasingly falling victims to pollution emitted thousands of miles away. It is warming up faster than anywhere on earth and its Inuit people are more seriously contaminated by toxic chemicals than those living in what are some of the most polluted parts of the planet.

"The Arctic is extremely vulnerable to projected climate change," reported the official Inter Governmental Panel on Climate Change, made up of more than 2,000 of the world's top scientists, last year. "It is likely to respond more severely than any other area on earth." Already there are signs that this is happening. Temperatures are rising and the area covered by ice is falling at an exponential rate.

Inuit people report that the ice is half as thick as it used to be, the amount of ice drifting down from the Arctic to the Greenland Sea has fallen by nearly half, and measurements under the North Pole have revealed "a large overall warming" of the water beneath the ice.

THE environmental group Greenpeace, which sent an expedition to the Arctic this year, reports that the community of Wainwright, in north-west Alaska, has been unable to hold its annual snow machine races over the frozen sea for the last few years because there has not been enough ice. Social life has suffered too: there was too little ice to use the machines for travelling in an area that has, of course, no roads.

The walls and ceilings of the cellars that the Inuit cut into the ice of the permafrost in Barrow, at the state's northernmost point, have been dripping water for the first time in living memory. And last year 100 experienced local whalers had to be rescued when the ice on which they were standing broke away from the shore near by.

Hannah Mendenhall, an Inuit from Kotzebue, western Alaska, told the Greenpeace researchers: "Whereas the elders had to wear mukluks [traditional boots of skin and fur], I can go around in tennis shoes all winter, and the kids can too. And they can wear shorts to school in the middle of winter and it doesn't bother them."

Trade and shipping should benefit. Experts expect that major shipping routes will open up across the Arctic Ocean as the ice melts, cutting days off journey times between Europe and the Far East. But the warming is already playing havoc with wildlife.

In recent years the number of caribou on Bathurst Island in the Canadian Arctic has fallen by over 95 per cent - from 24,320 animals in 1961 to 1,100 last year. The blame laid by scientists sounds paradoxical: increased snowfall. But that's because of the rise in temperature - normally it's too dry and cold to snow. The deer find it harder to dig through the deeper snow to find the moss and lichens they eat. Two years ago 10,000 reindeer died of starvation on the Chukotskiy Peninsula in the far north-east of Russia for this reason. Walrus may also suffer as the ice retreats into deeper water: they need ice thick enough to bear their weight over water shallow enough to enable them to dive to the sea bottom for food.

As the spring thaw comes earlier, and the autumn freeze-up later, the delicate balance of Arctic life is being upset. Polar bears are extremely vulnerable both to the vanishing ice and to poisonous chemicals in the Arctic. At the top of the food chain, they concentrate pesticides and other toxins picked up from the food they eat. And so do people.

The 450 Inuit people of Broughton Island, in the eastern Canadian Arctic live in an area traditionally so unsullied that there is no word in their language for "contamination". Yet it has been confirmed that their bodies contain the highest levels of dangerous polychlorinated biphenyls (PCBs) ever found, apart from in the victims of industrial accidents.

The chemicals - now largely banned in developed countries but once widely used in a host of applications from paints to pesticides, plastics to electrical equipment - are increasingly suspected of causing cancer, suppressing fertility and damaging the immune system. They are also thought to be "gender-benders", causing sperm counts to fall and bizarre sex changes in wildlife, in which male animals, fish and birds are now born with female sexual characteristics.

Inuit over a wide area from Greenland to Arctic Quebec have seven times as many PCBs in their bodies as people living in industrialised parts of Canada. And Greenlanders have more than 70 times the pesticide Hexaclorobenzene in their bodies than Canadians further south. Another pesticide, HCH, is over 100 times more concentrated in the waters of the Arctic Beaufort Sea than in the Java Sea, near to the place where it is mainly used.

How do people in such a relatively pure environment become so disproportionately contaminated with chemicals they do not use? Part of the answer is that the world acts as a giant distillery, picking up pollutants from where they are released and dropping them many thousands of miles away, making the roof of the earth its ultimate chemical dump. In this global distillation volatile chemicals boil off into the air when they are used in the tropics. They are carried by the winds until they hit a cold climate where they condense and fall to earth. Most end up in the Arctic, concentrating there because there is a relatively small area attracting pollution from the whole of the northern hemisphere. The cold slows down the decomposition of the chemicals, and they build up in the thick layers of blubber and fat that Arctic wildlife needs to survive. The Inuit are at the top of the food chain, eating a lot of local fish and wildlife, absorbing the chemicals in the process.

Smog now shrouds the Arctic in spring, so that if Santa were to look down on the North Pole from his sleigh, it would appear whisky brown not white. The pollution - largely sulphur compounds - comes from chimneys in North America, Europe and Russia.

The ozone layer over the Arctic has thinned by a tenth over the past 20 years, again as a result of pollutants released in industrialised countries. Different climatic conditions prevent a large hole opening up, as has happened in the Antarctic, but lots of mini-holes appear each year, as if in an Emmenthal cheese, exposing wildlife and people to harmful ultra- violet rays from the sun.

SO THE Arctic and its people - who contribute almost nothing to the world's pollution - are becoming its principal victims. And, by the same token, the problems cannot be tackled in the Arctic: answers have to be found globally. There are signs, at last, that governments are increasingly realising that they have to work together to tackle the global environmental crisis. The chemicals that cause ozone destruction have now - by international treaty - been phased out in rich countries, and are beginning to go in developing ones. Sulphur emissions have been greatly cut in industrialised nations under other treaties. The United Nations has been working on a treaty to control persistent toxic chemicals. And governments are slowly making progress on agreements to control global warming.

The problem is that there are huge time lags built into the world's natural system. The amount of ozone-damaging chemicals in the atmosphere should start to decline any time now: but they are so long-lasting that it will be a century before the protective ozone layer heals itself entirely.

The toxic chemicals are extremely persistent, and much of them are probably still working their way up to the Arctic, through global distillation, from releases emitted years ago. And those gases which have already been released from burning fossil fuels ensure that there will be a great deal of global warming whatever we do now: the best hope is to keep it to manageable proportions.

What happens in the Arctic will play an important part in this. For as the ice disappears, revealing dark land and sea, more heat from the sun will be absorbed rather than reflected again into space. And as the tundra thaws out it will release huge amounts of carbon dioxide and methane which will speed up global warming even further. So it may well be that the future of the world will be decided at the North Pole.