Michael Meacher: Cold comfort for those attending the Earth Summit

The Earth Summit in Johannesburg, in just three weeks' time, will confront an overarching agenda: fresh water, energy, poverty, food. A decade on from the inaugural conference at Rio, these fundamental issues remain as unresolved as ever, and not only in Sub-Saharan Africa.

A visit last month by a group of ministers to the other side of the world, the Arctic, showed just how poignant these issues are everywhere across the globe. One remark sticks in my mind. "The environment is our supermarket," said the Inuit woman, switching easily from Inuktitut (the Inuit language) to English when no translation was provided. "You go to the supermarket for food. We go out on the land to hunt, fish, trap and gather. Imagine for a moment the emotions we now feel – shock, panic, rage, grief – as we discover the food, which for generations has nourished us and keeps whole physically and spiritually, is now poisoning us."

The common picture of the Arctic as a place of melting glaciers and thinning polar bears is a travesty. The meaning of what is happening there is much more ominous for the rest of the world. Nor is it just a matter of the atmospheric drift to the Arctic of the Pops (persistent organic pollutants) which so distressed the Inuit by turning a pristine wilderness into a contaminated zone. It is the transformation of a culture, a way of living, indeed a means of survival, that sends a wake-up call to the planet.

But does it matter? Nunavut, a vast expanse formerly the Canadian North-West Territories, is extremely sparsely populated, with perhaps only 30,000 Inuit. But it is real. At the end of the day, computer models of climate change are just that, computer models. The Inuit bear witness not only to what is happening in their environment, but to what is going to happen further south, because it is happening in the Arctic first.

While the world has warmed by about 0.6ºC during the past century, average temperature changes in the Arctic as a whole have increased by at least twice as much, and some area by perhaps more than 10 times as much. An increase of 6ºC may not sound dramatic. But it is. At the last Ice Age, a sheet of ice two miles thick descended over the North American continent and over Europe and the Siberian plain when the average global temperature dropped by only 5ºC. If the rise in temperature which has already occurred in some parts of the Arctic were to become widespread across the globe, the consequences could be outside anything experienced in human history in the last quarter of a million years.

The two best-known markers of climate conditions in the Arctic are the extent of sea ice and permafrost. Permafrost thawing has already been extensive. A rate of decline of sea ice in the northern hemisphere has been documented by satellite data at almost 3 per cent per decade since 1978, when the records began. There is also evidence of substantial ice thinning.

Within the Arctic Ocean itself, the ice cover is reducing each year by an area almost as large as Belgium. In addition, the glaciers are melting extraordinarily fast, causing significant sea rise.

The impacts on human habitations are registered as erosion problems, landslides, draining of lakes, and destabilisation of roads and buildings as a result of melting permafrost. New species of insects, birds and mammals have been observed, including unwelcome ones such as the mosquito. The number of forest fires – and the area burned – has been increasing in the Yukon since the 1960s. Infestation of spruce bark beetle has devastated white spruce forests after several mild winters and springs. Emaciated polar bears have been seen in the Hudson Bay because the early break-up of the sea ice from which they hunt seals and other prey has forced them on to the land earlier, shortening their feeding season.

If such changes are already being witnessed, what of the next 50 or 100 years? Given that known feedback effects will accelerate warming in the Arctic, there are good grounds to expect that temperatures will rise much, much more than they already have done, and that the Arctic will also become wetter.

Canadian models project an ice-free summer season by 2050. The permafrost, whose temperature lies within a few degrees of 0C, is also highly sensitive to climate change. Animals dependent on sea ice and cold climates for their habitat, such as the polar bear, seal and musk ox, may be threatened with extinction. Entire ecosystems, or components within them, may already be near the their tolerance thresholds for key climate variables. Science is telling us to expect large change.

We should listen to that message and act on it, not least at the Johannesburg summit. Where the Arctic leads, the rest of the world will eventually follow. In the words of the Inuk leader from Kuujjuag in Nunavik (northern Quebec):

"We are the land and the land is us. We cannot stand by, waiting for slow-moving governments to step in and make everything right. If we can help people to see that a poisoned Inuk child, a poisoned Arctic and a poisoned planet are one and the same, we will have effected the change in people's awareness that we all need."

The author is the Minister for the Environment