last well into May. Or the snow clearing. Just let it melt!
I used to think that way myself—I, who grew up in the Arctic, in a time of proper winters generally lasting eight or nine months of the year. For most of my childhood, I lived in Norway’s coldest region, on the Finnmarksvidda mountain plateau. However, several harsh, snowy winters in Tromsø in the 1970s when we had to dig tunnels to our houses contributed to my decision to leave the region, and I moved to the much less snowy, but consequently much wetter, area of western Norway. And since it was still possible to go skiing even there as long as you went high enough up into the mountains, I didn’t miss the white stuff.
It was only when I came to much more southerly latitudes, to places where snow never fell and temperatures never came close to freezing, that I discovered the cryosphere. It was on the populous, sunbaked, sweltering Indo-Gangetic Plain in northern India and Bangladesh that I came to understand how important the cryosphere is. Because what was it that kept people here alive during the driest and hottest parts of the year? It was the snow and ice in the mountains, far off in the Himalayas, which aren’t even visible from the plain. When the rain no longer filled up the ever-dwindling rivers in the months before the monsoon, it was meltwater from the snow and glaciers on the Roof of the World that ensured the rivers never ran totally dry.
Almost nobody was talking about that back then in the nineties when I traveled around on the banks of the Ganges and its tributaries, making TV programs about the rivers and what they meant to people. Not that I was giving so much thought myself to what would happen if the glaciers vanished. But the glacial rivers from the Himalayas, Tibet, and nearby mountain ranges such as the Karakoram and the Pamirs sustain the lives of several hundred million people, well over a billion in fact if you include the great Chinese rivers that arise in Tibet. Later, I discovered that this is not a unique phenomenon: there are other places on the planet where snow and ice are also vital for keeping people, animals, and plants alive. This is particularly true of the countries around the Andes, where many of the largest cities are dependent on meltwater. Even fertile California is at the mercy of the cryosphere, as demonstrated recently when “the snows of yesteryear” ended up falling as rain and no longer served as a natural reservoir. So the Kingdom of Frost, the cryosphere, is vital for large swaths of the Earth’s population, especially in places where most people have never even seen either snow or ice.
But it is also more than a reservoir. As I immersed myself in the cryosphere and its history, I discovered that its significance dates far back in time and is much greater than the history books tell us: the frozen world has been an absolutely determining factor in the way life has developed here on our planet. Over the ages, its fluctuations—the dance of the white caps—have shaped landscapes, life, evolution, and, to a great extent, human history. Even phenomena as diverse as our upright posture, the first fields of grain, the modern-day border between Norway and Sweden, steam engines, automobile traffic, and the skills of chess grand master Magnus Carlsen and javelin thrower Andreas Thorkildsen have all been influenced by the cryosphere and its fluctuations. Not directly, but through the decisive influence the cryosphere has upon the climate—as we are in the process of discovering today.
— 2 —
BETWEEN FIRE AND ICE
ONE OF THE best things about Finnmarksvidda was the sky in winter. There were neither high mountains nor tall houses, so the stars and northern lights played freely across an endless 360-degree horizon. Best of all, there was no electric light to dull the light show in the heavens. The weather also tended to be clear on winter evenings.
Nowadays, the northern lights have become a tourist magnet, and people flock here from all over the world because you can enjoy them without freezing in northern Norway, thanks to the Gulf Stream. But for me, the clear starry sky was an equally unique show. And walking there, eyes turned upward, it was easy to wonder: Are there any other souls out there? Anyone who—right now—is asking whether there’s another planet like ours, with living creatures who go about wondering the same thing? Perhaps because the starry sky was so clear, thoughts like this occupied my mind so much in those days that I decided to study astronomy and physics when I grew up.
With the passage of time, though, my fascination ebbed away. Astronomy felt a bit otherworldly and I found other interests. When I returned to science, not as a scientist but as a communicator, what most preoccupied me were the mysteries of life. And not least the ultimate mystery: how life came about and how living organisms assumed ever more complex forms until, eventually, creatures emerged that were capable of pondering their own existence. Darwin became more important to me than Einstein, and the evolution of the human brain became more exciting to me than black holes. This preference also applied to my job as a science journalist, because the brain was still a newly discovered, unexplored continent.
So when NASA and other organizations began to report the discovery of Earth-like planets where there might be life, I was skeptical. Of course, the thought could stir your imagination: What if there really was somebody out there for us to talk to? But my reading about the development of life told me that we are the result of a series of almost impossible, or at any rate improbable, events. Life did not simply arise of its own accord, especially not complex life. This was something the evolutionary biologists John Maynard Smith and Eörs Szathmáry wrote about in The Origins of Life.4 They described eight transitions or revolutions life had to undergo before creatures like us could come about, living beings it was possible to communicate with. And to get all the way to this point, it was necessary to undergo all the transitions: there were no shortcuts.
The first transition was the emergence of self-replicating molecules, which created copies of themselves. Even this is still a mystery to biochemists, but the assumption is that RNA (the slightly less complex relative of DNA) may have been the first stage. We do not know if this was how it happened, and self-replication requires a combination of two mechanisms: not just a method for the actual replication (copying), but also a means of acquiring the energy needed to carry it out. Life must therefore have emerged in the vicinity of an energy source. And remember, this was long before life’s usual means of capturing energy, photosynthesis (which converts solar energy to biological energy), was “invented.” Some scientists, like biochemist Nick Lane, have therefore argued that the first living organisms must have arisen in or close to submarine hot springs or volcanoes.5
I won’t go through all eight stages proposed by Maynard Smith and Szathmáry, or Lane’s version of the development of life. Suffice it to say that it is theoretically possible to provide an explanation of how life on Earth evolved from simple, single-celled organisms, somewhere between 3.5 and 4 billion years ago, to more complex beings. That is not to say there is perfect clarity about all of the steps.
The story I will try to tell here—in a very short, simplified version—is how this development and life’s different revolutions have been intertwined with the history of the cryosphere.
The connection appears to have been there from the outset. It all started several billion years ago with a chunk of ice that came sailing through space and collided into a blazing hot Earth. This chunk of ice was a comet, and it was followed by a whole swarm of other comets and various celestial objects during the highly unstable early phase of our solar system’s history. These celestial objects brought many things with them—of which more later—but one crucial contribution was the substance that actually forms the cryosphere: water.
Because water is what it’s all about. Water in its many frozen forms: transparent ice, clear as glass, on the lakes; slop and slush on the roads; fern frost on frozen winter windowpanes; snowflakes drifting slowly through the air; compressed crystals beneath thousands of feet of glacier ice; black ice that suddenly springs up on the road sending cars into ditches; rime on withered straw in October; old spring snow that makes it impossible for animals and humans to get about; icebergs that strike ships in the night, sending hundreds of passengers out
