Forget polar bears, worry about humans

Forget polar bears, worry about humans. WHEN I was a postdoc, I was often short of money and used to earn a little extra cash by telling fortunes using a pack of 15th-century tarot cards. Like other practitioners, I was always praying that one card would not appear. It shows a grinning skeleton carrying a giant scythe standing above a field littered with severed heads. It is card number 13, Death, and few customers reward you generously after they encounter it.

Although I know the card well, I was still surprised when an image of it popped into my mind out on the Arctic seas, in the middle of a large field of broken ice floes some 1200 kilometres from the North Pole. I was in a ship that was cruising slowly off the long, low, snow-streaked island of SvenskeĆøya on the eastern side of Svalbard, researching a book about the Arctic.

In the far distance, a female polar bear was watching us. It was a mark of her great self-confidence that she immediately decided that our 100-metre-long ship might be worth hunting. She intercepted us quickly and tried to climb on board.

The side of the ship proved a little too high, so after half an hour of nibbling the ship's bow and scratching its sides, she tried a different strategy. She lay down on the edge of a nearby ice floe, gave a long yawn, folded her paws under her chin and apparently fell asleep. There was just something suspicious about her cocked ears.

Patient "still hunting" at the edge of an ice floe is the polar bear's number one technique for catching seals. A bear may sit or stand like this for an hour or more, utterly still but alert, until a seal surfaces for air. Then there is a flurry of bloody action. Knowing this, I was not much inclined to climb down onto the ice to take a close-up photograph, beautiful though she was.

Not long ago, tourists on ships passing through this region would amuse themselves by shooting polar bears. But since the 1970s, the Norwegian government has been protecting bears here with such seriousness that locals joke: "You are better off shooting a man than a bear - the authorities will investigate you less thoroughly."

That security no doubt helped give this female the swagger to hunt a large ship. Even so, she eventually grew bored, stood up and strolled off out to sea across a vast patchwork of broken ice floes, some not much bigger than herself. Her exit left me feeling sad. I already knew from the work of the US Geological Survey (USGS) that her grand-cubs may well be the last polar bears to live here. In 2008, the USGS combined models of the future state of the Arctic ice with what was known about the life of bears. Polar bears are utterly dependent on ice as a platform to hunt seals. As the Arctic summer ice disappears, the hunting period is growing shorter and breeding success is falling. Sometimes these days there is too much water to swim back to land and bears drown.

The bleak conclusion of one USGS model was "extirpation by 2050" for the bears of Svalbard. A few areas did better, but only in the frozen channels among the northerly Canadian islands might bears survive as rulers of the ice until the end of the century. These are grim forecasts but they are also conservative because they are based on models that aren't keeping up with the terrible speed of the ice's collapse.

In the far north, the biggest and fastest change to our planet ever caused by human activity is under way. As the Earth warms, more and more of the frozen Arctic seas are melting away. Each winter, the ice grows until it covers an area more than one and a half times as great as the US. In summer, that ice used to melt to half the winter area. Now, after a catastrophic collapse in 2007, close to two-thirds of the ice is vanishing. Compared with a decade earlier, the Arctic is losing an extra area of ice each summer six times as large as California. Estimates of when the ice will completely disappear each summer now range from 2013 to 2050.

Other charismatic Arctic beasts will also struggle. After the bear, the narwhal is most at risk. Off the coast of northern Greenland in 2008 I had the good fortune to see narwhal surface among the ice. For a brief moment, three improbably long spiral horns broke through the water and waved above the sea like magic wands. One animal twisted around and, for a second, his grey, wet body glistened in the low sunlight. Then all three dived and were gone.

Under threat, too, will be the walrus, so recently recovered from mass commercial hunting, the white beluga whale and the bowhead whale, which is still only slowly gaining numbers after centuries of slaughter. All use ice to rest, hide or feed.

Hearing this, you might think it is obvious why the image of Death came to my mind. But it is not so simple. Although I always found it hard to reassure anxious customers, the real meaning of the card is transformation. A death is an ending and a new beginning, and that is what I was seeing as I travelled round the Arctic.

A great transformation is under way. The change from ice to water is an end for many familiar creatures but, in a wider sense, it is not an end. The Arctic is being reborn as a sea that is more similar to southerly seas. Whales, fish, birds and plankton that are more at home in warmer waters are already invading the Arctic. Off the coast of Alaska, for example, pollock are moving north, bringing also the salmon that feed on them. This is the beginning of a new Arctic ecosystem that is forming as the old Arctic dies. As yet, we cannot see the exact shape of the new world, or how many of its older inhabitants will hang on in remote, icier spots. But we can guess who will be its new ruler, the top predator which will topple the polar bear from its throne.

We cannot see the exact shape of the new Arctic but we can guess its new ruler

Already, in the far north, I have seen pods of killer whales. These animals have a tail fin that makes it hard for them to surface where there is much thick ice. The disappearance of the ice is increasingly exposing the beluga, narwhal and bowhead to this ferocious predator. In some parts of the Arctic, beluga whale, known as the canary of the sea for their constant chattering, have fallen silent. Killer whales are close and are listening out for prey.

In purely biological terms, the new Arctic will be more productive than the old, because there is more water, open to sunlight for longer, with more plankton growing in it, and more food supports more life. The first signs are already there. After the sudden collapse of the sea ice in 2007, a satellite-borne sensor, measuring the water's "greenness", showed that the total productivity of the Arctic seas leapt by 40 per cent. That is a big increase.

Louis Fortier, a marine biologist at Laval University in Quebec, Canada, explained it like this: "If you look at it simply from the point of view of biological productivity, that will increase as the ice disappears. It's just that the life there, the specialists which we are all fond of, like the polar bear, the walrus and some other species which we have in our unconscious mind, are going to get into trouble."

Is there comfort in knowing that polar bears hunting on ice will be replaced by killer whales swimming in a warmer, more productive sea? For me, the answer is "not much", but it will be the consequence of what we have done to Earth. And looking at the changes to the Arctic as a transformation does lead to a larger thought. For too long, too many fruitless efforts to combat climate change have been billed as "Saving the Planet". Right now, in the last week or two before the climate negotiations at Copenhagen, there are few signs of dramatic action. Perhaps that is because the message is wrong. As the changes in the Arctic show, the planet continues. Species come and species go. The planet does not need saving, even from us.

Species come, species go. The planet does not need saving, even from us

Far better that the urgent need to reduce greenhouse gas emissions is portrayed as simple self-interest; that we focus on the coming losses of agricultural production, the droughts, the mass migrations and political instability that will follow rapid climate change. Political will might be better stiffened by listening to generals rather than to environmentalists. As a former head of the US Central Command, Anthony Zinni, explained, if we don't pay the price to reduce greenhouse gas emissions today, "we will pay the price later in military terms".

Then we might turn again to the far north, not to worry about bears, but in fear of the Arctic's revenge (New Scientist, 28 March, p 32). For millions of years, the brilliant white ice around the North Pole has reflected the summer sunlight back into space, helping cool the planet. As the ice turns sea dark and soaks up the sun, global warming will really take off. Already the signs are there: in areas where the sea ice has gone, summer temperatures are between 3 °C and 5 °C higher than the average of the previous 20 years.

As the differences in temperature between the Arctic and the equator lessen, the weather and rain patterns all over the northern hemisphere are altering. As the new Arctic sea heats up, a pool of warm air is spreading across the nearby lands. Shrubs and trees are creeping north across the tundra. Dark vegetation soaks up more heat and the warming gains pace. Methane is bubbling from tundra lakes and shallow shelf seas as the permafrost at their bottoms thaws and micro-organisms digest their carbon.

Elsewhere, the top layer of permafrost is rotting away. It contains enough carbon to more than double the carbon dioxide in the atmosphere, taking us back to an era when temperatures were more than 7 °C higher than they are now.

Of course, the carbon will not be released all at once. Instead, the Arctic will favour a long, slow revenge, spread over hundreds of years. As well as this, with the same painful slowness, the melting ice caps will make sea levels rise perhaps a metre this century and then every century for a thousand years. Once these changes really get going, they will be unstoppable.

If these thoughts don't make people wake up, then we really are in deep trouble. As it happens, there's a tarot card for those who can't change, which was just as unpopular as Death with my customers. It is number 15: "blind abandonment to self-destructive materialism".

Its symbol is the Devil.
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