Greenland
Written in the rock and ice of Greenland, if we know how to read it, is the story of the planet’s past and dark hints as to its future. Minik Rosing knows how to read part of it. Half Danish, half Greenlander, Rosing calls himself an apprentice Eskimo. He was born in a small settlement near the Greenland capital, Nuuk. Many such settlements were closed down by the Danish government, which has ruled Greenland since 1721. The scattered populations were moved into coastal towns, where boredom and alcoholism set in. Rosing’s birthplace, though, just ceased to exist when the family left. ‘We closed it down ourselves,’ he said. When he and his brothers needed to go to school, his parents had moved to Denmark. ‘That was pretty much it,’ he said.
Rosing’s brothers chose professions that they could bring back to Greenland: one became an architect, the other a doctor; they both live in Nuuk. Minik became a geologist. Now a professor in Copenhagen, he returns to Greenland to probe the story written in its rocks. In 1999, he stumbled across a rock that was to backdate the beginnings of life on earth by one billion years.
The rock lies in Isua, a boulder-strewn valley high in the mountains above the Nuuk fjord. It was a valley that excited geologists because it was known to be the home of some of the oldest rocks on the planet. We reached it by helicopter, flying up the long fjord and into the forbidding mountain landscape, dusted that summer afternoon with a light covering of snow.
‘Greenland has a memory of four billion years of the history of the earth,’ Rosing said. ‘I didn’t go there expecting to find life, but I was very interested in what Earth was like then. These rocks are 3,800 million years old and they were formed on the surface of the earth so they contain a picture of what conditions were like. They are a snapshot of the very beginnings.’
But a lot has happened in that valley since then: rocks of different ages are jumbled together, creating static in the record. Rosing was trying to develop a theory of observation: how to read the rocks in their environment, how to distinguish which characteristics belonged to their moment of origin and which came later.
‘For a geologist that valley was like being lost in Tokyo and not knowing the language, not being able to read any signs. Then I saw this outcrop — and it was as though I had met a cousin who could explain everything,’ he said. ‘It was a window back in time.’ The earth was young when this rock was formed, just 700 million years old. The sun was seventy-five per cent weaker and lunar meteor showers set off violent explosions. The continents had not yet emerged. It was not much more promising than anywhere else in the universe as a place where life might begin. The rock was sedimented in clearly identifiable layers. Rosing took samples back to his lab in Copenhagen.
A snowstorm started as he spoke. Flakes of snow swirled around us, cold descended. ‘The first thing you do with a rock like that is take a sliver twenty-five microns thick and put it under a microscope. At first I was disappointed. I thought it was dirty and it was hard to resolve. Then I realized that the dirt was part of the rock. It was unambiguously carbon. The only way carbon gets into a rock is through organic material separating it out. So then I had a rock that was full of carbon — and it was from the sea floor, which meant that it was not a freak occurrence.’
It took ten years from the first discovery to analyze the rock and publish the results. When he did, it proved that life had formed from the very beginnings of the earth one billion years earlier than had previously been thought. The carbon was the result of photosynthesis: irrefutable evidence of life.
The scientists in the group talked about life as though it had a personality. Life, one of them said, invented photosynthesis to store the energy from the sun. From this beginning all else follows — the regulated health of the planet that made it possible for humans to evolve in a brief moment of geological time, between the last ice age and the present.
Greenland tells the story of life on Earth in other ways. The ice cap is a detailed record of the Earth’s atmosphere that goes back 100,000 years. The Ilulissat ice fjord is one of the pulses that scientists are taking to diagnose the fever that is gripping Greenland. What they are finding is full of omens. High up on the ice cap they probe the moulins — the deep holes that have appeared in the glaciers, internal cataracts that accelerate the melting of the ice, eating it out from inside. Greenland’s ice cap is roaring with internal torrents, dripping and running, melting and dissolving. Since the summer of 1992, when teams of scientists extracted two complete ice-core samples from its summit, they have been able to study the climate record for the last 100,000 years, through the Holocene and the last glaciation to the previous interglacial, reading the mix of gases in the ice bubbles that track the cooling and warming of the planet. What they have found has revolutionized their understanding of climate: instead of a pattern of gradual change, they have learned that the story of the Earth’s climate has been punctuated by sudden shifts from warm to cold, abrupt and unexplained reversals, some happening in the course of a few years. It does not matter to life on the planet, but it matters a great deal to human beings, who have built their complex societies within dangerously narrow boundaries of tolerance.
The oceanographers, the Arctic scientists, the ice specialists, the biologists and botanists voice their growing alarm at the catalogue of unusual events — the unprecedented Arctic winter temperature shifts that leave reindeer herds pawing at sheet ice unable to reach the lichens on which they feed, the plagues of insects that can strip a boreal forest in a season, the alterations in animal migration patterns and, above all, the gathering pace of the thaw. Bob Corell, an American scientist who studies the ice cap, has watched the Sermeq Kujalleq glacier double its speed in the last ten years. ‘Seven per cent of the ice that leaves Greenland comes from here,’ he said. ‘Ten years ago the glacier was moving at three to four kilometres a year. By 2003 it was measured at eight kilometres a year. The ice is more permeable than we thought, and the glacier is melting from within. It’s sitting on water now and it is speeding up.’ The pace of melting is causing the scientific literature to be rewritten. ‘We didn’t used to believe that ice could permeate all the way down a glacier,’ he said. ‘Glacial earthquakes are increasing, and now we think that this might destabilize the lower slopes. It could collapse very suddenly.’