Unusual incidents are being reported across the Arctic. Inuit(因纽特人) families going off on snowmobiles to prepare their summer hunting camps have found themselves cut off from home by a sea of mud. There are also reports of sea ice breaking up earlier than usual, carrying seals beyond the reach of hunters. Climate change may still be a rather abstract idea to most of us, but in the Arctic it is already having great effects---if summertime ice continues to shrink at its present rate, the Arctic Ocean could soon become almost ice-free in summer. The knock- on effects(连锁反应) are likely to include more warming, cloudier skies, and higher sea levels. Scientists are increasingly eager to find out what's going on in the Arctic.

    For the Inuit the problem is urgent. They live in unsteady balance with one of the environments on earth. Climate change, whatever its causes, is a direct danger to their way of life. Nobody knows the Arctic as well as the locals, which is why they are not content simply to stand back and let outside experts tell them what's happening. In Canada, where the Inuit people are trying hard to guard their hard-won autonomy in the country's newest land, Nunavut, they believe their best hope of survival in this changing environment lies in combining their ancestral knowledge with the best of modern science. This is a challenge in itself.

    The Canadian Arctic is a vast, treeless polar desert that's covered with snow for most of the year. Adventure into this area and you get some idea of the hardships facing anyone who calls this home. Farming is out of the question and nature offers few pickings. Humans first settled in the Arctic a mere 4,500 years ago, surviving by taking advantage of sea first. The environment tested them to the limits: sometimes the settlers were successful; sometimes they failed and disappeared. But around a thousand years ago, one group appeared that was uniquely well adapted to deal with the Arctic environment. These Thule people moved in from Alaska, bringing dogs, iron tools and the like. They are the ancestors of today's Inuit people.

    Life for the descendants(后代) of the Thule people is still tough. Nunavut is 1.9 million square kilometers of rock and ice, and a handful of islands around the North Pole. It's currently home to 2,500 people, all but a handful of them Inuit. Over the past 40 years, most have abandoned their nomadic(游牧的) ways and settled in the area's 28 isolated communities, but they still rely heavily on nature to provide food and clothing.

    Supplies available in local shops have to be flown into Nunavut on one of the most costly air networks in the world, or brought by supply ship during the few ice-free weeks of summer. It would cost a family around ￡7,000 a year to replace meat they obtained themselves through hunting with imported meat. Economic opportunities are few, and for many people state benefits are their only income.