His hamlet (population 330) is a prime nesting ground for a variety of birds, but last summer the 44-year-old hunter and guide spotted a type of owl he had never seen that far north. For the first time, he also saw a dragonfly in his Inuit community.

“We don't have dragonflies around, but I've seen one,” Mr. Tautu said. “This was just out in our backyard and I was pretty surprised to see one.”

Changes to the environment and climate are usually imperceptible and are visible only when the increments build up over time and result in a trend. But in the summer of 2007, both anecdotal and quantifiable evidence emerged that showed dramatic changes are taking place in the Far North at a faster pace than anyone imagined.

Scientists scattered throughout the Arctic, and those monitoring satellite data as part of International Polar Year programs, couldn't have timed their research any better.

“The summer of 2007 was stunning,” said Doug Bancroft, director of Environment Canada's Canadian Ice Service.

The Northern Hemisphere is normally covered with 7.5 to 8.5 million square kilometres of ice on average, based on five decades of record keeping. The amount of ice coverage shrank to a low of 5.3 million square kilometres in the summer of 2005.

But on Sept. 17, 2007, scientists calculated that the amount of sea ice hit a new record low of just 4.2 million square kilometres.

A NASA-led study released this week, which also recorded the staggering decline in the amount of perennial sea ice, found the bulk of the thickest ice is now confined to the Arctic Ocean north of Canada. But even that isn't immune to the thaw.

The fabled Northwest Passage is normally still choked with ice during the summer. At its usual low point, 14 per cent of the shipping route remains covered with ice, which prevents ships from passing unless escorted by icebreakers. This year, just 2 per cent was covered with ice, resulting in the second consecutive summer during which an unaided sailboat could pass through.

“Along the 2,300 kilometres of the Northwest Passage you're going around ice for about 20 kilometres as opposed to the usual 400,” Mr. Bancroft said.

A consensus has grown in the scientific community that global warming caused by human activity is contributing to the changing face of the Arctic. But experts say it was the peculiar weather Mother Nature offered up last summer – whatever caused it – that is largely to blame for the recent unusual events. There was a high-pressure system that sat over the Arctic for much of the summer. It shooed away clouds, leaving the sun alone to beat down. That created higher ocean temperatures, which in turn accelerated the melt.

Son Nghiem, who led that NASA study on sea ice released this week, also pointed to unusual winds, which compressed sea ice, pushing it into the Transpolar Drift Stream and into warmer water where melting happened more quickly.

Scott Lamoureux, a geography professor at Queen's University in Kingston, noticed the summer's odd weather firsthand on Melville Island north of the Arctic Circle where he's studying how climate change is affecting river flow, soil moisture, vegetation and water quality. That far north, the mean temperature has been reported at just under 5 C in July since records were first kept in the 1950s.

“What we observed through much of July were temperatures in the 15-to-20 C range. The highest temperature recorded was almost 22 C,” Prof. Lamoureux said.

He also noted other weird things he hadn't noticed in his five years working there.

While the summer melt usually sinks 50 centimetres into the permafrost, the melt depth was down at least a metre or more this year. That caused land to fracture, as well as large slides and flooding. One piece of land slid down a hill and dammed a river 200 metres across, he said.

“It's not surprising that this kind of thing could happen, but it's the scale and how rapidly it could occur,” Prof. Lamoureux said. “The impact of this, even if it's the only time it happens for the next decade, could be felt on the system for many, many years.”

Only recently has the world begun to notice the potential impact of climate change on northern wildlife, plants and people. This year, the dire warnings piled up.

Until now, climate models were predicting that the Arctic would be free of sea ice in the summertime by 2040, 2050 or at the latest 2100, according to Mr. Bancroft. Now, 2030 is a more realistic date for that biggest melt of all.

“We're a decade ahead of the worst-case scenario,” he said.

Even with moderate projections for shrinking sea ice, the U.S. Geological Survey concluded last month that two-thirds of the world's polar bears – there are an estimated 22,000 – will vanish by 2050, and could disappear entirely from Alaska.

“Sea-ice conditions would have to be substantially better than even the most conservative computer simulations of warming and sea ice” in order to prevent the projected drop in the number of bears, the report says.

NASA even warned that with so much Arctic ice melt, the planet may be hitting a tipping point. The thaw may become a self-sustaining acceleration. As the ice shrinks, so does the amount of reflective snow and ice, which in turn leaves the ocean to draw in more heat from the sun. Warmer waters, of course, melt ice more quickly.

The Potsdam Institute for Climate Impact Research in Germany has pronounced that Arctic sea ice has “already tipped.”

Back in Chesterfield Inlet yesterday, the snow was flying and the freeze was setting in. “It still looks normal,” Mr. Tautu said. He's not worried about a big melt, figuring the polar bears, other animals and people will adapt. Snow and ice, he said, will always be there. Still, he added, times have changed since his elders could read the weather better than any scientist.

“I was taught about the weather when I was a little boy,” he said. “Nowadays we can't predict it any more.”