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The Planet Remade

How Geoengineering Could Change the World

PRINCETON UNIVERSITY PRESS

The Top of the World

One might say that immensity is a philosophical category of daydream. Daydream undoubtedly feeds on all kinds of sights, but through a sort of natural inclination, it contemplates grandeur. And this contemplation produces an attitude that is so special, an inner state so unlike any other, that the daydream transports the dreamer outside the immediate world to a world that has the mark of infinity Gaston Bachelard, The Poetics of Space (1958)

The sun is shining, but the sky above is Bible black. It takes on colour only lower down, first deep violet, then, just above the encircling horizon, a band of blue and white. The descending, brightening sweep of colour gives a swelling curve to the sky.

Within that encompassing blue-white band, the bright-below Earth, too, is curved. It bends away in every direction towards its blue-lipped rim.

The only straight line in this whole vast, round, empty world is the wing.

You are 22 kilometres up, well inside the stratosphere – a realm which, although it is about as peripheral as a part of the Earth can be, plays a central role in the story to come. If climate geoengineering ever takes place, there is a good chance that it will take place up here, in the Earth's attic. If it does not take place, it may well be for fear of the damage it could do to this bright-lit void.

Even if it were not a crucial locale for geoengineering schemes, though, the stratosphere would still have much to recommend it as the starting point for a book about the environment, its protection and its politics. Its short history – it was discovered only in 1902 – weaves together threads of scientific exploration, military ambition and environmental concern. Beyond that, though, in its liminal way the stratosphere seems to me a perfect setting in which to begin a book which looks at the way the earthsystem works and ways it might work differently, a book about the boundaries between physical planets and imagined worlds.

You are an inhabitant of the Earth's surface who has, in all likelihood, seen more of that surface than your ancestors would have dreamed possible; you are probably the sort of person who can imagine crossing an ocean for a holiday: and so you think that you know the Earth. But less than a day's walk vertically above you, your planet offers an environment beyond your ken, a realm without local features or breathable air, a windy but oddly weatherless stack of atmospheric layers sliding around from equator to pole without storms or clouds. The rules that govern the workings of the lower atmosphere are turned on their head up here, and common-sense ideas about the world you have picked up on its surface hold no sway. In understanding the world below, science can feel like an optional extra. Here it is indispensable.

The stratosphere is closed – a volume of about 15 billion cubic kilometres with well-defined boundaries at its base and at its top. At the same time as being finite, though, it is all-encompassing – no bit of the world below lacks a stratosphere above, no trip beyond the world can avoid passing through it. In this, it is a realm not simply described by science, but oddly akin to science itself: limited but all-encompassing. Like the stratosphere, science is, in its way, alien to everyone; it is at the same time, and by the same measure, common to all, sheltering the just and unjust alike. It provides a viewpoint from which the world is bigger and stranger than it seems from the surface. The world thus revealed is more abstract, too, and there is no denying that something is lost in that. Yet a sort of universality is gained, and a liberating rootlessness.

I prize that rootlessness. I also worry about it. That is why, in our thinking, I would not have our scientifically informed imaginations waltz around this vast curving ballroom completely unconstrained, like dancing giants of the mind. That is why I insist, as you look out to the blue-white-bright horizon, that you also see the wing, straight and true and joined to your point of view. Because there must be a wing. With the exception of the very occasional balloon, it is only with wings that people rise this high into the stratosphere. And I would not ask you to picture this abstract not-quite-place, this featureless more-than-place, without also having you acknowledge the means by which people come to see such things.

There are stratospheres around other planets. Mars has one; so does Jupiter, and Saturn; Saturn's moon Titan is in the club, too. Spacecraft have measured their heights and their temperatures and sent profiles of them back to Earth – just as orbiters closer to hand have done for the Earth's own stratosphere. But that Earthly stratosphere is not just known from the outside, as the others are, in the planetary way; up here, on the wing, you see it from within, in the way that worlds are seen. There have been no births in this part of the world, though there have been deaths, and few have spent much time here. But what those few achieved here has had human impact. What could be seen from up here helped to determine the early course of the cold war. The damage that might be done to this thinnest of airs did much to define the evolving global environmental consciousness of the 1970s and 1980s. Nor do you have to enter this high realm to partake, a little, of its splendour. Everyone who has ever treasured the quality of light just after sunset, where the blue scattering of the stratosphere comes into its own, has felt their world touched by this planetary periphery. Like all stratospheres, that of the Earth is tied to what lies beneath it by gravity and radiative-transfer mechanisms and atmospheric dynamics. But there are also ties of history, politics and wonder.

A paramount expression of those ties is the wing, and that which the wing entails; the people who worked the moulding and riveting, who designed the cross section, who defined the mission, who built the company that built the aircraft, who elected the politicians who contracted for the aircraft to be built. Without all of them, you couldn't see all of this. Even in a daydream of almost empty immensity, I insist on this rule: you can't imagine the end without imagining the means. And the means are human.

The wing tip edges up. The harsh sun arcs gently across the sky.

Discovering the Stratosphere

The wing is shaped as it is, long, strong-shouldered but thin, because that is what it takes to lift you this high. You are as far above an everyday airliner as that airliner would be above the ground. The surface far below stretches in vast ambit. The horizon would be almost 600 kilometres away were it not obscured by haze and cloud. Those impediments, too, are far below you. No normal cloud can come close to this height, nor could any mountain; the planet's crust would buckle under the weight of a peak that tall. If there were a mountain range built on top of summer thunderclouds, their spreading anvil tops forming its buried roots, you would still pass over its peaks with ease.

You are not just far above the land and sea and cloud. You are above most of the air, as well. Nine-tenths of the atmosphere is below you. What is left is too thin to breathe, too thin to hold warmth, too thin to brighten the night-black sky. The everyday sky of lower places is blue because of the way the molecules of the atmosphere break up sunlight. The longer wavelengths, the reds and greens and yellows, pass through the air relatively unscathed; but the blue, short-waved and flighty, is diffused. While the rest of the light takes a direct route from sun to surface, some of the scattered blue spreads itself across the vault of the sky. Up at 22 kilometres, though, the sunlight has not seen enough molecules for much scattering to take place. That is why the sky above is black and the untwinkling stars shine steadfast and true. You are only just this side of the edge of space.

That is not the only difference. In the lower atmosphere, the air gets colder as you rise higher. For centuries scientists had believed that this was a constant trend – that the air got thinner and colder until it petered out altogether in the vacuum of space. It was because of this deep belief that Léon Teisserenc de Bort, who discovered and named the stratosphere at the turn of the twentieth century, was so surprised when the instruments he was sending up into the sky on balloons seemed to show that, above a certain height, the air got no cooler. Sometimes it even warmed – surely there was some sort of mistake? But after balloons by their dozens had told him the same thing, he decided that there wasn't.

The discovery de Bort announced in 1902 came to be seen as 'the greatest ever made in meteorology', in the words of an English scientist a generation later, because the way the atmosphere changes temperature with height is fundamental to how it behaves. Warm air is buoyant, and rises. In the warmed-from-below air near the surface this buoyancy keeps everything in a state of flux; warm air endlessly rises into the colder air above, stirring things up and causing a great deal of weather. But in the realm to which de Bort had sent his balloons, this cooling trend not only stopped, it was reversed. Warmer air sat on top of cooler air, leaving no scope for buoyancy to create instability; circulation in the stratosphere, it was to turn out, was side to side, not up and down. Layering was not just possible, it was inevitable. Hence de Bort's name for the new realm he had discovered: the stratosphere is so called because stratos means layer. The lower atmosphere, in contrast, he dubbed the troposphere, from tropos, to turn or stir.

At the end of the nineteenth century dividing the Earth into concentric spheres with Greek prefixes was becoming popular, a terminological expression of a deeper shift in the way people thought and talked about the planet. The first scientists to take the study of the Earth as their particular domain had been geologists, and they had come to the Earth through rocks, rocks that could be admired in landscapes, collected for museums and mined for money. Their Earth was primarily a history, because it was history, they came to understand, that explained which rocks were to be found where. They sliced up the history of the world ever more finely in space and time, all the time arguing over the sequence and nature of the events for which they thought they saw evidence.

The physicists who turned their imaginations to the planet as a whole (and to other planets too) towards the end of the nineteenth century took a different approach. Only by emphasizing the whole over the parts and the idealized over the specific could the numerical approaches they prized be brought to bear on their new subject. They found dividing the Earth into simplified spheres much more congenial than dividing its history into hard-to-perceive periods. So under the atmosphere (a term which had, as it happened, first been applied to imagined gases around the moon, and only later used to describe the air around the Earth) there was a lithosphere – the stiff rocky shell of the Earth's surface – and a hydrosphere – the oceans. By the early twentieth century all sorts of specialists wanted spheres of their own; glaciologists termed the icy parts of the world the cryosphere, soil scientists took as their subject the pedosphere. Seismologists discovered new spheres within the Earth, atmospheric physicists found new ones in the sky; they eventually stacked three ever-more-tenuous shells – the mesosphere, the thermosphere and the exosphere – on top of the stratosphere.

Those higher realms, though, quickly become otherworldly. They cannot be reached with wings and only barely with balloons; they were not explored before the age of rockets. The stratosphere is the highest realm humans have visited, rather than simply passed through. The first of them to do so, 30 years after its discovery, peered out of tiny windows in metal gondolas hung beneath vast balloons. They rose up in part for adventure, in part for glory, in part for science. There were strange radiations at the top of the world: hard ultraviolet light not seen in the lower atmosphere; the newly discovered 'cosmic rays' held by some to be the birth pangs of new matter. Their more fanciful chroniclers saw the stratonauts pushed up against the boundaries of humankind's narrow reality; Gerald Heard, who wrote science commentaries for the BBC in the 1930s, talked of them being poised to feel the 'untamed energy of the outer universe', of coming close to 'that ocean of energy in which all the suns and raging stars are but mist and spray'. This sense of being on the edge of immensity is at the heart of the experience of the sublime, a response to the power and scope of nature which, in the words of Edmund Burke, 'fills the mind with grand ideas, and turns the soul in upon itself'. The stratosphere, then and now, offered the sublime in heady drafts.

After the Second World War, flights to the stratosphere became much more common, and wing-borne to boot. They became less about what lay beyond, and more about what sat below; they also became much more predominantly American. In partially taming some droplets of Heard's ocean of energy, the Manhattan Project changed the way strategists thought about power on a planetary scale. They found in the stratosphere a frontier-free high ground from which the warriors in charge of the new nuclear arsenals could look down; America's first great expression of global power, the B-52 bomber, was accordingly named the Stratofortress. The nuclear age also realigned the interests of the military and those of scientists. Geophysicists, aware that, unlike other physicists, they were largely bereft of laboratories, had come to think of the upper atmosphere as something akin to a replacement, a natural laboratory, and the military, impressed by what physicists had put into the bomb bays of its Stratofortresses, proved happy to offer them better access to it, with rockets and new sorts of aircraft. It also offered them new opportunities to experiment in it.

If there is an emblem for this view of the world, it is the Lockheed U-2, created to serve America's national security, still flying more than 50 years later in the name of science. A remarkable reconnaissance aircraft conceived, built and flown in utter secrecy, it took its pilots far higher than a B-52 could, up to the heights where this chapter began, heights beyond the reach, at least at first, of any interceptors or anti-aircraft missiles. There, the U-2 pilots carried out one of the most important missions of the cold war, attempting to count and pinpoint the USSR's nuclear weapons. From an impervious height, the U-2's elite pilots used cameras finer than any made before to gaze in near omniscience on a world that seemed all but limitless.

And yet, as they did so, the pilots themselves were subject to the tightest of limits. They could see across whole countries; but they could not scratch their own noses, their faces trapped within the helmets of pressure suits no pilots before them had needed. Their wings spanned 40 metres; but they could not stretch their arms or legs, or even reach all the controls in their cockpit without makeshift tools.

Their flight was made possible by the work of thousands of people down below, work carried out at the behest of governments that represented millions more. Yet in the early days of the U-2, the pilots were as alone as it is possible to be, flying thousands of kilometres across enemy territory in radio silence for hour after hour, navigating by the diamond-steady stars (their cockpits had sextants built in). And for all the unimpeded weather-free emptiness of their realm, their flight was constrained within the tightest of aerodynamic envelopes. In air that thin, the difference between flying too fast – and thus being struck down by turbulence – and flying too slow – and thus stalling – was about 20 kilometres an hour. Bank too steeply, and one wingtip would start to tremble as the other stopped providing any lift at all. The pilots had a name for this constraint. They called it the coffin corner.

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Excerpted from The Planet Remade by Oliver Morton. Copyright © 2015 ABQ72 Ltd. Excerpted by permission of PRINCETON UNIVERSITY PRESS.
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