Anawak watched the sun hover on the horizon. 'You're right,' he said.

And then, impulsively, he told Akesuk everything that they'd been told at the Chateau, about what they were working on and what they suspected about the intelligent beings in the sea. He knew he was breaking Li's instructions, but he didn't care. He'd been silent all his life. Akesuk was all the family he had left.

His uncle listened. 'Would you like to hear the advice of a shaman?' he asked finally.

'I don't believe in shamans.'

'Who does? But this isn't a problem you can solve with science. A shaman would tell you that you're dealing with spirits, the spirits of the once-living that now inhabit the Earth's creatures. The qalhinaat started destroying life. They angered the spirits, the spirit of the sea, Sedna. No matter who these beings are, you won't achieve anything by trying to fight them.'

'So what do we do?'

'See them as a part of yourselves. The world is such a small place, or so they're always telling us, but the truth is, we're still aliens to each other. Make contact with them, just as you're making contact with the alien world of the Inuit. Wouldn't it be a good thing if the divisions were healed?'

'They're not people, Iji.'

'That's not the point. They're part of our world, just as your hands and feet are part of your body. No one can ever win the struggle for mastery. Battles only ever end in death. Who cares how many species there are on the planet and which is more intelligent than the rest? Learn to understand them instead of fighting them.'

'Sounds fairly Christian to me. Turn the other cheek and all that.'

'Oh, no,' chuckled Akesuk. 'It's the advice of a shaman. There are still plenty of shamans around. We just don't make a big deal of it.'

'Which shaman would…' Anawak raised his eyebrows. 'You're not saying that… ?'

Akesuk grinned. 'Well, someone has to provide spiritual counsel.' He paused. 'Look!'

A short distance away an enormous polar bear was tucking into the narwhal carcass, scaring away the birds, which scattered into the air or scuttled over the ice at a respectful distance. A petrel launched an airborne assault, but the bear scarcely noticed. It wasn't close enough to the camp for the sentry to sound the alarm, but the man had cocked his gun, his eyes trained on the site.

'Nanuq,' said Akesuk. 'The polar bear smells everything, including us.'

Anawak watched the bear. He wasn't afraid. After a while the enormous creature lost interest and moved away majestically. It turned its head and cast an inquisitive look at the camp, then disappeared behind a wall of pack ice.

'See how sedately it moves,' his uncle whispered. 'But that bear can run, my boy. You bet it can run.' He chuckled, then reached into his anorak and pulled out a little sculpture that he placed on Anawak's lap. 'I've been waiting to give this to you. There's a right time for every present and maybe this is the right moment for you to have this.'

Anawak picked up the carving. A human face with feathers for hair, mounted on the body of a bird. 'A bird spirit?'

'Yes.' Akesuk nodded. 'Toonoo Sharky, one of our neighbours, made it. He's famous now. The Museum of Modern Art has bought his work. Take it. There are challenges ahead of you. You're going to need it. It will guide your thoughts in the right direction when it's time.'

'Time for what?'

'Your consciousness will soar.' Akesuk's hands became wings 'But you've been away for a long time. You're out of practice. Maybe you need someone to tell you what the bird spirit sees.'

'You're talking in riddles.'

'That's the privilege of the shaman.'

A bird crossed the sky above them.

'A Ross's gull,' said Akesuk. 'Now you're really lucky, Leon. Did you know that thousands of birdwatchers come here every year to see a gull like that? That's how rare they are. Well, you've got nothing to worry about. The spirits have sent you a sign.'

Later, in his sleeping-bag, Anawak lay awake for a while. The midnight sun shone through the fabric of the tent. He heard the sentry shout, 'Nanuq, nanuq!' He thought of the Arctic Ocean and imagined the unknown world below. He drifted until he came to the top of an iceberg that had been formed by a glacier in Greenland before the current had swept it towards the east coast of Bylot Island, where it had frozen into position. Eventually the wind and waves had freed it from the ice and sent it further south. In his dream Anawak climbed a narrow snow-covered path to the summit of the iceberg. A lake of emerald-green meltwater had formed there. Everywhere he looked, he saw the smooth, blue sea. In time the iceberg would melt, sending him to the bottom of the calm water and the source of all life, where a puzzle waited to be solved.

Perhaps a shaman would be there to help him.

24 May

Frost

Dr Stanley Frost had his own take on the situation. Surveys carried out by the energy industry located the main marine deposits of methane hydrate in the Pacific, along the west coast of North America and near Japan. More reserves had been found in the Sea of Okhotsk, the Bering Sea and further north in the Beaufort Sea. In the Atlantic, America had the bulk of the deposits right on her doorstep. Sizeable areas were known to exist in the Caribbean and off the coast of Venezuela, while the seabed around Drake Passage, stretching between South America and the Antarctic, was also rich in hydrates. Before the collapse of the slope, the deposits off the coast of Norway had been charted, as had the hydrates in the eastern Mediterranean and the Black Sea.

But methane deposits seemed thin on the ground off the northwestern coast of Africa, particularly in the vicinity of the Canary Islands.

And, in Frost's view, that didn't make sense.

The Canary Islands were in an up-welling zone, where cold, nutrient-rich water rose from the depths, stimulating the growth of plankton, which in turn encouraged fish stocks. On that basis, the seabed surrounding the Canary Islands should have been covered with hydrates since methane collected in the depths wherever organic life filled the sea.

The difference in the Canaries was that the decaying matter had nowhere to settle. The islands had formed millions of years ago as a result of volcanic eruptions, and they rose steeply from the seabed like towers. Tenerife, Gran Canaria, La Palma, Gomera, El Hierro – the pinnacles of volcanic rock loomed up from the ocean floor from depths of 3000-3500 metres. Sediment and organic matter swirled down their sheer sides without settling. That was why conventional charts didn't indicate the presence of methane deposits in the Canaries, and that – in Frost's estimation – was the first miscalculation.

He suspected that the seamounts, of which the Canary Islands formed the visible peaks, weren't as sheer as had generally been supposed. There was no denying that they were steep, but they were by no means smooth and vertical. Frost had studied the formation of volcanoes for long enough to know that even the most precipitous strato-volcanoes were scarred with ridges and terraces. It was his firm opinion that large quantities of hydrates were present in the Canaries, and that people hadn't found them because they hadn't looked properly. In this instance, the hydrates wouldn't be lying in chunks on the seabed: they'd be running through the rock in thin veins. And Frost was in no doubt that they'd be found on the terraces too, wherever sediment had settled.

Since Frost was a volcanologist and not a hydrates expert, he'd called on Bohrmann for help. Frost had drawn up a list of islands that were potentially at risk: La Palma, then Hawaii and Cape Verde, followed by Tristan da Cunha further south, and Reunion in the Indian Ocean. They were all potential time-bombs, but La Palma posed by far the biggest threat. If Frost's fears turned out to be justified then the Cumbre Vieja ridge on La Palma was a Sword of Damocles, hanging over the lives of millions of people, from a height of two thousand metres.