The melting north

STANDING ON THE Greenland ice cap, it is obvious why restless modern man so reveres wild places. Everywhere you look, ice draws the eye, squeezed and chiselled by a unique coincidence of forces. Gormenghastian ice ridges, silver and lapis blue, ice mounds and other frozen contortions are minutely observable in the clear Arctic air. The great glaciers impose order on the icy sprawl, flowing down to a semi-frozen sea.

The ice cap is still, frozen in perturbation. There is not a breath of wind, no engine's sound, no bird's cry, no hubbub at all. Instead of noise, there is its absence. You feel it as a pressure behind the temples and, if you listen hard, as a phantom roar. For generations of frosty-whiskered European explorers, and still today, the ice sheet is synonymous with the power of nature.

The Arctic is one of the world's least explored and last wild places. Even the names of its seas and rivers are unfamiliar, though many are vast. Siberia's Yenisey and Lena each carries more water to the sea than the Mississippi or the Nile. Greenland, the world's biggest island, is six times the size of Germany. Yet it has a population of just 57,000, mostly Inuit scattered in tiny coastal settlements. In the whole of the Arctic—roughly defined as the Arctic Circle and a narrow margin to the south (see map)—there are barely 4m people, around half of whom live in a few cheerless post-Soviet cities such as Murmansk and Magadan. In most of the rest, including much of Siberia, northern Alaska, northern Canada, Greenland and northern Scandinavia, there is hardly anyone. Yet the region is anything but inviolate.

Fast forward

A heat map of the world, colour-coded for temperature change, shows the Arctic in sizzling maroon. Since 1951 it has warmed roughly twice as much as the global average. In that period the temperature in Greenland has gone up by 1.5°C, compared with around 0.7°C globally. This disparity is expected to continue. A 2°C increase in global temperatures—which appears inevitable as greenhouse-gas emissions soar—would mean Arctic warming of 3-6°C.

Almost all Arctic glaciers have receded. The area of Arctic land covered by snow in early summer has shrunk by almost a fifth since 1966. But it is the Arctic Ocean that is most changed. In the 1970s, 80s and 90s the minimum extent of polar pack ice fell by around 8% per decade. Then, in 2007, the sea ice crashed, melting to a summer minimum of 4.3m sq km (1.7m square miles), close to half the average for the 1960s and 24% below the previous minimum, set in 2005. This left the north-west passage, a sea lane through Canada's 36,000-island Arctic Archipelago, ice-free for the first time in memory.

Scientists, scrambling to explain this, found that in 2007 every natural variation, including warm weather, clear skies and warm currents, had lined up to reinforce the seasonal melt. But last year there was no such remarkable coincidence: it was as normal as the Arctic gets these days. And the sea ice still shrank to almost the same extent.

There is no serious doubt about the basic cause of the warming. It is, in the Arctic as everywhere, the result of an increase in heat-trapping atmospheric gases, mainly carbon dioxide released when fossil fuels are burned. Because the atmosphere is shedding less solar heat, it is warming—a physical effect predicted back in 1896 by Svante Arrhenius, a Swedish scientist. But why is the Arctic warming faster than other places?

Consider, first, how very sensitive to temperature change the Arctic is because of where it is. In both hemispheres the climate system shifts heat from the steamy equator to the frozen pole. But in the north the exchange is much more efficient. This is partly because of the lofty mountain ranges of Europe, Asia and America that help mix warm and cold fronts, much as boulders churn water in a stream. Antarctica, surrounded by the vast southern seas, is subject to much less atmospheric mixing.

The land masses that encircle the Arctic also prevent the polar oceans revolving around it as they do around Antarctica. Instead they surge, north-south, between the Arctic land masses in a gigantic exchange of cold and warm water: the Pacific pours through the Bering Strait, between Siberia and Alaska, and the Atlantic through the Fram Strait, between Greenland and Norway's Svalbard archipelago.

That keeps the average annual temperature for the high Arctic (the northernmost fringes of land and the sea beyond) at a relatively sultry -15°C; much of the rest is close to melting-point for much of the year. Even modest warming can therefore have a dramatic effect on the region's ecosystems. The Antarctic is also warming, but with an average annual temperature of -57°C it will take more than a few hot summers for this to become obvious.

The albedo effect

The efficient north-south mixing of air may also play a part in the Arctic's amplified warming. The winds that rush northwards carry pollutants, including soot from European and Asian smokestacks, which has a powerful warming effect over snow. In recent decades there has also been a rise in levels of mercury, a by-product of burning coal, in the tissues of beluga whales, walruses and polar bears, all of which the Inuit eat. This is another reason why the Arctic is not virgin.

But the main reason for Arctic amplification is the warming effect of replacing light-coloured snow and ice with darker-coloured land or water. Because dark surfaces absorb more heat than light ones, this causes local warming, which melts more snow and ice, revealing more dark land or water, and so on. Known as the albedo effect, this turns out to be a more powerful positive feedback than most researchers had expected. Most climate models predicted that the Arctic Ocean could be ice-free in summer by the end of this century; an analysis published in 2009 in Geophysical Research Letters suggested it might happen as early as 2037. Some now think it will be sooner.

It is hard to exaggerate how dramatic this is. Perhaps not since the felling of America's vast forests in the 19th century, or possibly since the razing of China's and western Europe's great forests a thousand years before that, has the world seen such a spectacular environmental change. The consequences for Arctic ecosystems will be swingeing.

As their ancient ice buffers vanish, Arctic coastlines are eroding; parts of Alaska are receding at 14 metres (45 feet) a year. Niche habitats, such as meltwater pools on multi-year ice, are dwindling. Some highly specialised Arctic species will probably become extinct as their habitats shrink and southern interlopers rush in. Others will thrive. The early signs of this biological reshuffle are already evident. High-Arctic species, including the polar bear, are struggling. Species new to the region, such as mackerel and Atlantic cod, are coming up in Arctic trawler nets. Yet the shock waves of Arctic change will be felt much more widely.

Melting sea ice will not affect global sea levels, because floating ice displaces its own mass in seawater. But melting glaciers will, and the Arctic's are shedding ice at a great rate. Greenland's ice cap is losing an estimated 200 gigatonnes of ice a year, enough to supply a billion people with water. The Arctic's smaller ice caps and glaciers together are losing a similar amount. Before this became clear, the Intergovernmental Panel on Climate Change (IPCC) had predicted a sea-level rise of up to 59cm during this century. Given what is happening up north, many now think this too modest.

Melting sea ice will not affect global sea levels, because floating ice displaces its own mass in seawater. But melting glaciers will

A wilder fear is that a deluge of Arctic meltwater could disrupt the mighty “overturning circulation” of the global oceans, the exchange of warm tropical and cold polar water. It has happened before, at least seven times in the past 60,000 years, and needs watching. But recent evidence suggests that such a calamity is not imminent. Another concern, that thawing Arctic permafrost could release vast quantities of carbon dioxide and methane, looms larger. That, too, has happened before, around 55m years ago, leading to a global temperature increase of 5°C in a few thousand years.

Such risks are hard to pin down, and possibly small. Many elements of the change in the Arctic, including the rates of snow melt and glacier retreat, are still within the range of historical variations. Yet the fact that the change is man-made is unprecedented, which introduces huge uncertainty about how far and fast it will proceed. For those minded to ignore the risks, it is worth noting that even the more extreme predictions of Arctic warming have been outpaced by what has happened in reality.

Riches of the north

In the long run the unfrozen north could cause devastation. But, paradoxically, in the meantime no Arctic species will profit from it as much as the one causing it: humans. Disappearing sea ice may spell the end of the last Eskimo cultures, but hardly anyone lives in an igloo these days anyway. And the great melt is going to make a lot of people rich.

Watch our animation of the receding Arctic ice-shelf and the shipping routes it could unlock

As the frozen tundra retreats northwards, large areas of the Arctic will become suitable for agriculture. An increasingly early Arctic spring could increase plant growth by up to 25%. That would allow Greenlanders to grow more than the paltry 100 tonnes of potatoes they manage now. And much more valuable materials will become increasingly accessible. The Arctic is already a big source of minerals, including zinc in Alaska, gold in Canada, iron in Sweden and nickel in Russia, and there is plenty more to mine.

The Arctic also has oil and gas, probably lots. Exploration licences are now being issued across the region, in the United States, Canada, Greenland, Norway and Russia. On April 18th ExxonMobil finalised the terms of a deal with Russia's Rosneft to invest up to $500 billion in developing offshore reserves, including in Russia's Arctic Kara sea. Oil companies do not like to talk about it, but this points to another positive feedback from the melt. Climate change caused by burning fossil fuels will allow more Arctic hydrocarbons to be extracted and burned.

These new Arctic industries will not emerge overnight. There is still plenty of sea ice to make the north exceptionally tough and expensive to work in; 24-hour-a-day winter darkness and Arctic cyclones make it tougher still. Most of the current exploration is unlikely to lead to hydrocarbon production for a decade at least. But in time it will happen. The prize is huge, and oil companies and Arctic governments are determined to claim it. Shortly before the ExxonMobil-Rosneft deal was announced, Vladimir Putin, Russia's president, announced plans to make it much more attractive for foreigners to invest in Russian offshore energy production. “Offshore fields, especially in the Arctic, are without any exaggeration our strategic reserve for the 21st century,” he said.

For half the 20th century the Arctic, as the shortest route between Russia and America, was the likeliest theatre for a nuclear war, and some see potential for fresh conflict in its opening. Russia and Canada, the two biggest Arctic countries by area, have encouraged this fear: the Arctic stirs fierce nationalist sentiment in both. With a new regard to their northern areas, some of the eight Arctic countries are, in a modest way, remilitarising them. Norway shifted its military command centre to the Arctic town of Reitan in 2009. Russia is replacing and upgrading its six nuclear icebreakers, a piece of civilian infrastructure with implications for security too. Yet this special report will suggest that warnings about Arctic conflict are, like the climate, overcooked.

The Arctic is no terra nullius. Unlike Antarctica, which is governed by an international treaty, most of it is demarcated. Of half a dozen territorial disputes in the region, the biggest is probably between the United States and Canada, over the status of the north-west passage. Those two countries will not go to war. And the majority of Arctic countries are members of NATO.

Yet the melting Arctic will have geostrategic consequences beyond helping a bunch of resource-fattened countries to get fatter. An obvious one is the potentially disruptive effect of new trade routes. Sailing along the coast of Siberia by the north-east passage, or Northern Sea Route (NSR), as Russians and mariners call it, cuts the distance between western Europe and east Asia by roughly a third. The passage is now open for four or five months a year and is getting more traffic. In 2010 only four ships used the NSR; last year 34 did, in both directions, including tankers, refrigerated vessels carrying fish and even a cruise liner.

Asia's big exporters, China, Japan and South Korea, are already investing in ice-capable vessels, or planning to do so. For Russia, which has big plans to develop the sea lane with trans-shipment hubs and other infrastructure, this is a double boon. It will help it get Arctic resources to market faster and also, as the NSR becomes increasingly viable, diversify its hydrocarbon-addicted economy.

There are risks in this, of dispute if not war, which will require management. What is good for Russia may be bad for Egypt, which last year earned over $5 billion in revenues from the Suez Canal, an alternative east-west shipping route. So it is good that the regional club, the Arctic Council, is showing promise. Under Scandinavian direction for the past half-decade, it has elicited an impressive amount of Arctic co-operation, including on scientific research, mapping and resource development.

Yet how to reconcile the environmental risks of the melting Arctic with the economic opportunities it will present? The shrinkage of the sea ice is no less a result of human hands than the ploughing of the prairies. It might even turn out as lucrative. But the costs will also be huge. Unique ecosystems, and perhaps many species, will be lost in a tide of environmental change. The cause is global pollution, and the risks it carries are likewise global. The Arctic, no longer distant or inviolable, has emerged, almost overnight, as a powerful symbol of the age of man.