There is a clear view from the high point of the glacier in Ammassilik, East Greenland. To the north, behind me, you can see fifty miles up to the highest range of mountains. To the west, there is a huge iceberg-dotted fiord and the main ice cap of central Greenland. But looking around closer by, you ask, where is all the ice? At the top, instead of the expected ice cap, there is this honey-coloured rock, scoured into deep grooves by the passage of old ice. Here, on this summit spot in July, the ice has already gone. Everywhere the ice has retreated deep into the shady hollows of the mountains. Lower down, paths which just last summer cut across glacier ice now pass amid the soft moraines left behind as the glaciers draw back. High up, where I am now, the silence of the mountains is profound. But listen carefully and your ears begin to pick up a faint background sound. Walk down to where the glacier remains and the sound become clearer. It is water trickling away beneath the ice as the Arctic melts.

Here you don't find so many people asking "what's all the fuss about global warming", as Freeman Dyson does in his recent controversial defence of "heretical" views of climate change on Edge [2]. Climate change has arrived. Any Inuit hunter living in the nearby villages can tell you what they see. The sea ice melts earlier and earlier in the spring. Well-known winter routes across the ice that connect hunting areas can't necessarily be trusted any more. The ice may be too thin. You need smart and well-trained lead dogs on your sledge team to sense the ice and keep you safe. The arrival of fish and the passage of whales are changing. You'll hear the same lament from Inuit all over the Arctic. "The narwhal used to come right up to this bay," they told me at a settlement in Ellesmere Island, "but now the ice is all different and we don't know where they go."

I'm up in Greenland along with the celebrated photo-essayist John McConnico, who took picture above, because I am reporting on the future of the Arctic. And it's not that I just want to lament the end of the polar bear, though hard times for the bear and other creatures that rely on sea ice are looking more than likely.

I think there is a lot more to it than that. This is one of the regions of the world that will change first and fastest as a result of climate change. There will be losers but there may be winners too (on this I would agree with a heresy of Dyson). And there will be wrenching change, startling technological developments and political strife. It will be a microcosm of what will happen elsewhere.

First and foremost, of course, we would like to know what to expect. And here I would agree, just for a moment, with half of another of Dyson's heresies. Our models of climate change do not entirely capture "the real world we live in". We do know that temperatures are rising faster in the Arctic than almost any other place and that the extent of the sea ice is shrinking with dramatic speed but our models aren't accurate.  That said, Dyson is totally wrong with the second half of his criticism, that the climate experts end up believing their own imperfect models when they should "put on winter clothes and measure what is really happening".

Scientists are totally aware of the shortcomings of their models and up here in the Arctic they are gathering data with unprecedented energy. Now that International Polar year has begun, there are going to be more scientists up in the Arctic that at any time in history. They need that data to validate their models and satellite observations. They are coming in icebreakers, helicopters and planes. Some are even coming aboard air ships, on floating ice floes (an 8 month trip to the pole from Russia aboard an "ice station") and on foot, with two Belgian scientists having just completed the walk from Russia to Greenland. Some will fly underwater planes beneath the ice. Yes, they have their winter clothes on and it's exactly their adventures and the new data that they generate that I am following for my book.

Knowing that Arctic climate models are imperfect, it would be reassuring for me, if not for the scientists, to be able to write that scientists keep making grim predictions that just that don't come true. If that were so, we could follow Dyson's line that the models aren't so good and "the fuss is exaggerated". Scarily, the truth is the other way around. The ice is melting faster than the grimmest of the scientist's predictions, and the predictions keep getting grimmer. Now we are talking about an Arctic free of ice in summer by 2040. That's a lot of melting given that, in the long, dark winter the ice covers an area greater than that of the entire United States.

Some of that fresh water stored up in the Arctic Ocean might find its way out into the Atlantic, as happened during the Great Salinity Anomaly of the 1970s, giving the Arctic a chance for revenge on the rest of the planet. Repeated on a larger scale, the fresh water has the potential to change ocean currents and world climate. 
Still, I am excited by the prospect that there might be winners from climate change. The Arctic contains vast reserves of gas and oil (25% of the world's undeveloped hydrocarbons), minerals and even diamonds. A new gold rush is already beginning. Norway is just completing its huge "Snow White" gas development off northern Norway.  Russia will ship oil in new ice-breaking tankers out of the top of Siberia and has just begun work on the enormous Shtokman field, 350 miles off its Arctic coast and a technological challenge beyond anything so far attempted in the Arctic. As the ice melts, the Northern Passage around Siberia will open to commercial shipping, cutting costs off the voyage to Europe from Japan and China. An even shorter direct route close to the North Pole may follow and then the Northwest Passage around Canada. Fish will provide another treasure. Most of the world's commercial fish come from the colder waters away from the tropics. Already the retreating ice is opening up seas that have potential as rich, new fishing grounds. The people who see a new frontier in the Arctic are some of the most remarkable men and women I've met, prepared to make huge financial gambles and push technology to new limits. Environmentalists may not like them but they are part of the story of climate change too.

The emerging riches of the region lead to the next part of the story—the awakening of geopolitical rivalries as a result of climate change. The US, Canada, Russia, Norway and the Danish territory of Greenland all face one other around the Arctic Ocean. They all claim rights to bits of it and are all in dispute. Russia has already claimed the seas up to the North Pole, recently depositing a titanium flag on the sea bed at the pole to make that clear. The circumpolar powers are beginning to worry about how to project power in the Arctic. Last month, the Canadian government ordered a new fleet of ice breakers to reinforce its territorial claims and began opening new military bases in the high Arctic.

For better or worse, the Arctic is going to see some exciting times. With a bit of luck, and if the US signs up to the Law of the Sea, the claims to different bits of the Arctic may be resolved scientifically, rather than militarily, through surveys of the sea bed to determine whose continental shelf extends where and how far. But there is still a lesson for the second of Dyson's declared big heresies, "the wet Sahara".

Climate change might actually bring the wetter climate of the Sahara of six thousand years ago back and Dyson argues that the "warm climate of six thousand years ago with the wet Sahara is to be preferred, and that increasing carbon dioxide in the atmosphere may help to bring it back".  So we should believe that climate change may make life hard on some parts of the planet but open a new Eden elsewhere and we should not make a "fuss". The problem, of course, is that as the incipient signs of strife in the Arctic show, the planet's losers from climate change are hardly likely to make it to a new green land without a war.