18 Miles
The Epic Drama of Our Atmosphere and Its Weather
Christopher Dewdney
Contents
Introduction
1. Stormy with a Chance of Life
2. The Wild Blue Yonder
3. Cloud Nine
4. The Poem of Earth
5. The Secret Life of Storms
6. Katrina
7. Palace of the Winds
8. Which Way the Wind Blows
9. Apollo’s Chariot
10. A Cold Place
11. Climate Change Past and Present
12. Weather That Changed History
Postscript: Fire, Water, Earth, Air
Appendix: Measurement Conversions
Selected Bibliography
Acknowledgments
Index
About the Author
Copyright
Introduction
“Sunshine is delicious, rain is refreshing, wind braces us up, snow is exhilarating; there really is no such thing as bad weather, only different kinds of good weather.”
John Ruskin
You’d never guess it but we live in a world flatter than a sheet of paper. Shrink the Earth to the size of a basketball and our atmosphere would be as thick as a layer of food wrap. The oceans likewise. Two of the most critical elements for our survival, water and air, are relatively scarce commodities. We are like microorganisms living in an evanescent fluid film, a dampness that would burn off like morning dew if the sun increased its solar output by just 15 percent.
Astronauts know all of this. From the space station, they see the tops of clouds spread out at the surface of the atmosphere like smoke beneath glass. And slipping back under that thin blanket of air is a real challenge. Their reentry angle can be no shallower than 5.3° and no steeper than 7.7° — too shallow and they will ricochet into deep space, too steep and they will burn to a crisp.
Yet it’s also a question of scale. The vantage from here, from Earth’s surface, is of another order entirely. The sky seems to go on forever. When a waning moon shines by day, it looks to me as if it’s suspended in the same blue atmosphere I breathe. No wonder Icarus dreamed of flying to the sun. And the immeasurable vastness of clouds, taller than mountains, what could contain that immensity?
For us, the atmosphere is a theater beyond reckoning, a massive, transparent stage for the drama of the skies. Every sunset is a light show; every storm a nail-biting, colossal thriller. Weather inspires our emotions and sometimes seems to reflect them. There is nothing more romantic than a rainy evening for newlyweds on their honeymoon, and how many philosophers have paced through windy streets deep in thought?
When I was a boy, the wind was a mood, a way of being, a kind of delirium that called me out of my house. I raced the leaves blowing along the street or stood at the edge of the ravine to hear the wind’s soft thunder in my ears. Clouds were another mood. At sunset, they transformed into dreamlike landscapes inviting the secret empire of night. I was fascinated by weather. Every season was a new universe, the next chapter in an epic story I made up as I went along.
January found me at a research station in Antarctica in the ravine behind my parents’ house. There I braved subzero blizzards to map glaciers with my special team of explorers, handpicked from neighborhood friends. Once, with amazing luck, we unearthed the frozen carcass of a mammoth, and on another expedition there was a time warp in the middle of a particularly dense snowfall, and we came face-to-face with a snarling saber-toothed tiger that charged out of the blizzard. Fortunately, we survived.
One hot July, there was a softball game followed by an expedition to explore the upper reaches of the Amazon in the same ravine — the raucous calls of howler monkeys echoed through the rainforest while treacherous Komodo dragons rustled in the undergrowth. We came upon the forest trails of lost tribes, sometimes catching glimpses of their ocher-painted skin as they disappeared around the bend of a trail. Of course, since then I’ve discovered that mammoths didn’t visit Antarctica, nor do Komodo dragons inhabit Brazil, but I’ve never lost my deep connection with climate and weather.
When I was a little older, in my early teens, I was fascinated by weather forecasts. Forecasters were scientific magicians who could conjure storms out of a sunny afternoon. From Weather: A Golden Nature Guide, a book my parents bought me, I began to learn the weather signs: a ring around the sun meant rain within one to two days; earth glow on the moon (when the dark side of a half-moon is faintly visible) was the reflection of masses of white clouds to the west, an almost sure sign of rain to come. There were illustrations of hurricanes and tornadoes and sun dogs. Now I was really hooked.
Then one afternoon, while leafing through my new copy of the Edmund Scientific mail-order catalog, among the usual assortment of tempting items — ant farms, glow-in-the-dark stick-on stars, aquariums, test tubes — I noticed a new item, a complete home weather station that included an outdoor anemometer (those whirling wind cups that measure wind speed). I had to have it. I saved my allowance and made extra money doing yard work.
When the package arrived, it was a little smaller than I expected, but everything was in there, including the glorious anemometer with its three wind cups. I blew on them and they twirled obediently, orbiting the little mast. There was also a separate spar for the wind vane, and both had connections for wires that led to my indoor instrument panel. All I had to do was install the wind vane and anemometer high enough to give accurate readings, which wouldn’t be easy. It meant I had to make a trek to the top of my parents’ house.
The afternoon of the installation was cool and windy. I climbed out of an attic window that was barely big enough to squeeze through and then screwed the base for both masts into the wooden gable above the dormer at the peak of the house. I imagined being captured by a National Geographic photographer as I braved the harsh mountain gales to install my weather station. After setting up the anemometer and wind vane, I connected the wires and threw the loose coils over the eaves in the general direction of my bedroom window below. Then I clambered back inside.
In my bedroom, I snared the dangling wires with a rake and pulled them through the window. I’d already installed the two wall-mounted, battery-powered weather gauges that the wires would connect to, one for wind velocity and the other for wind direction. Then came the moment of truth — if nothing happened, if the instrument panel was dead, I’d have to trek back to the roof to check the connections. I hooked up the wires, and the gauges danced to life.
The directional gauge was a circular compass with a little arrow that pointed out the wind direction in tandem with the vane on the roof mast. The velocity gauge was horizontal with a needle indicator — like an old-fashioned speedometer in an automobile dashboard — that showed a wavering wind speed of about 20 miles per hour. I was euphoric. Along with the barometer and window thermometer that I’d previously mounted, I now had a professional indoor weather station. I could take instrument readings from the comfort of my own bedroom no matter what the weather outside, and, more importantly, I could make my own weather forecasts, going mano a mano against the evening news’ weatherman.
By combining weather signs with instrument readings, I became a pretty good forecaster. I learned that a halo around the moon at night along with falling barometric pressure meant that it would probably rain within 18 to 48 hours. When an east wind shifted to the west and the cloud bases got higher and the barometer was rising, fair weather usually followed. In the winter, a north wind that shifted counterclockwise to become a west wind and then a southerly wind meant that snow was likely within a day.
Later I discovered that I could make pretty good predictions — especially of stormy weather — using only wind direction and my barometer. If the wind was blowing out of the south and then shifted to the east and my barometer was 29.8 inches or below and falling rapidly, a severe storm was imminent. The same was true if the wind shifted from east to north, especially in the winter and my barometer again was showing 29.8 inches or below and falling rapidly. I usually compared my results to the evening news’ weather report. I wasn’t always right — there were some things I just couldn’t see coming without a satellite view and upper-atmosphere readings — but I did pretty well considering.
But for all the quantitative data I was now receiving, my love of weather remained visceral, aesthetic even. The instrument panel just underlined the meteorological drama. A howling gale, even if gusts were measured at 50 miles per hour, was still a howling gale, with all the excitement of the wind roaring through the trees and garbage cans blowing down the street. Somehow the science permitted an illusion if not of control then at least perhaps a complicity of sorts. I was part of the weather.
Today I like to think of myself as a connoisseur of weather, an epicurean of hourly changes. Perhaps it’s a consequence of being a writer, or maybe I’m just meteorologically sensitive, but I’m very susceptible to the moods of weather. I revel in certain hot, overcast August afternoons with a ceiling of featureless, rainless stratus clouds. It’s the brightest light possible without casting any shadows, only a gathering of darkness under the parked cars or trees in the park. I like a similar sky on October afternoons when the undersides of the clouds are quilted, and the gray light seems to amplify the fiery reds and oranges in the autumn foliage.
There’s magic to urban evenings just after the sun sets and the city lights the bottoms of scattered cumulus clouds. They become islands between which stars ride an indigo blue ocean. And in July there are windy, hot summer afternoons, clear and dry, sometimes followed by equally windy summer nights where even the Milky Way seems to be adrift. I have seen sunsets as astonishing as fireworks, like surreal Sistine ceilings that stretched from horizon to horizon, and I remember foggy mornings like mysteries that dissolve the world. As T.S. Eliot wrote about ocean fog in his poem “Marina,” “What seas what shores what gray rocks and what islands / What water lapping the bow / And scent of pine and the woodthrush singing through the fog.”
What exquisite atmospheric nuance — a boat in the fog, where scent and song are the only beacons. Eliot’s fog conceals our highest spiritual aspirations and yet also evokes our devastating ignorance. As a species, we have so much left to understand and yet our yearning is our beacon. In a way, we’re like astronauts riding flaming ships through the sky on their return to Earth; we can only have faith. The astronauts know our atmosphere is a narrow, fragile margin, but they also know that it’s a magnificent realm — at once gorgeous, terrifying, capricious and elusive.
1
Stormy with a Chance of Life
The Improbable Birth of Our Atmosphere
The fortuitous creation of Earth took place about 4.5 billion years ago. A billion years is a long while. To get an idea of the immensity of such a span, imagine time could be condensed into a substance and that each year deposited a gram — the weight of a ballpoint pen cap or a dollar bill. If you added each year to the next, a decade would weigh 10 grams and a normal human life span would be 80 to 90 grams, about the weight of a chocolate bar.
Suppose we kept going — every year backward adding another gram to the lump — then 2,000 years, back to the time of the Roman Empire, it would weigh an easily hefted two kilograms, or as much as a small sack of potatoes. Spool back 200,000 years to the first anatomically modern humans, and you’re getting close to the limit of what an Olympic weightlifter can clean and jerk, around 200 kilograms.
Go further back to the dinosaurs, 60 million years ago, and your gram-a-year interest account cashes out at 53 tons, about the weight of a small diesel locomotive. Five hundred million years ago, at the beginning of what paleontologists call the Ordovician period, when our oceans were populated with trilobites and crinoids, the yearly deposits would weigh in at about 50,000 tons, or the approximate weight of three Ohio-class nuclear submarines. Four and a half billion years ago, when our planet first coalesced from primordial dust, your gram-a-year investment would weigh as much as an asteroid, one big enough to wipe out life on an entire continent.
Back then, our planet collided with impactors the size of our time-deposit asteroid every few hundred million years or so. Despite this constant pummeling, our molten planet had enough time to let gravity sort its constituent parts into layers — iron at the core and lighter minerals and elements arrayed above. The lightest of these, the gases, formed the top layer. At the time, these were hydrogen and helium, and they formed Earth’s first atmosphere. Think of the Hindenburg disaster: just one match and the whole works would’ve exploded. But you could strike a thousand matches 4.5 billion years ago without producing a single spark. There was no oxygen. Anyway, why would you bother? You’d be asphyxiating. And with all that helium around your squeaky last words would be comically high pitched, in a macabre sort of way.
But helium is a fickle gas, and it didn’t stick around long. Less than a hundred million years after Earth’s formation, most of it had escaped Earth’s gravity and fled into space. Unbonded gaseous hydrogen followed helium shortly afterward, leaving behind an atmosphere that had transformed into a pungent mixture of nitrogen, water vapor, carbon dioxide and hydrogen sulfide. Eau de rotten eggs. Beneath this odiferous miasma was a watery planet studded with a few transient islands of rock. It took another 300 million years for the Earth’s crust to stabilize into a thin layer of congealed lava over the primeval magma, yet even then whatever proto-continents had managed to poke their landmass above the oceans were pelted by meteors and asteroids. In fact, every few hundred million years, when a particularly large asteroid struck, the oceans evaporated in the subsequent planetary inferno. For thousands of years afterward, the seas bided their time as atmospheric steam and only reformed when the surface of the planet had cooled to the point where rain no longer vaporized instantly on the red-hot surface but began to accumulate in puddles, lakes and finally oceans.
In the midst of these hydrogen tempests, meteor bombardments and constant volcanic eruptions, the most extraordinary development on Earth took place — self-reproducing organisms with rudimentary DNA appeared. And, as it turned out, these diminutive creatures packed quite an atmospheric punch.
The Primordial Soup
Is there a hyperbole or superlative that can begin to capture how unlikely was the appearance of life? I think not. Life’s emergence rivals, perhaps even surpasses, the sudden materialization of the universe itself, conjured ex nihilo over 10 billion years ago. But what is life? How can we characterize this special case of matter taking on such extraordinary abilities? Maybe I make too much of it. Perhaps life is, as a character drolly referred to it in Thomas Mann’s The Magic Mountain, merely “an infectious disease of matter.” But how did it start? How did inanimate molecules begin to copy themselves and persevere?
That’s a question we have no detailed answer to. But we have a very informed general idea, and it goes something like this — life came from bad weather. It didn’t begin on a calm planet with tranquil seas and light breezes; it started on a planet that had terrific storms, howling winds and waves hundreds of feet tall. Self-assembling molecules began to arrange themselves in the midst of volcanic eruptions and meteorite bombardments. They flourished in an agitated saline broth constantly electrified by lightning, scalded with lava and cooked by a young sun wielding dangerously high UV levels.
Alexander Oparin was the first scientist to envisage this alchemical, Frankensteinian jump-start to life. In his 1924 “primordial soup” theory, he speculated that ultraviolet light acting on elemental gases, liquids and solids in an oxygen-free environment created organ
ic proteins, the basic constituents of life. Almost 30 years later, in 1953, Oparin’s theory was vindicated by an ingenious and now famous laboratory experiment by Nobel laureate Harold Urey and his graduate student Stanley Miller. At the University of Chicago, they filled a series of beakers, glass tubing and electrical circuits with hydrogen, water and methane, seeking to reproduce the conditions on our planet as they were four billion years ago. For days, they zapped their broth with electricity to simulate the storms that raged across the ancient seas, and after only a week, 15 percent of the carbon in this shocked concoction had formed no less than 23 amino acids, the building blocks of complex life. They had proven that organic molecules could indeed have formed spontaneously from inorganic constituents.
There have been many critics of the theory since then, particularly creationists, of which one was my family’s plumber, Gordon Lane. I remember watching him melt solder with a blowtorch to join two copper pipes under our bathroom sink when I was eight years old. Often he would stay for supper. He was a Jehovah’s Witness with a Mensa IQ and, like my father, had a penchant for puns. He loved nothing better than to take on our agnostic family in fundamental arguments. He was particularly dismissive of the primordial soup explanation for the beginning of life. He knew the odds against assembling a simple cell were catastrophically immense, and he was right. A simple protein like collagen, for example, is a molecule with 1,055 sequences that have to be in exactly the right order to function. And that’s just one of several hundred thousand proteins. He used a wonderful metaphor to underscore his argument against random mutations creating life-forms. “If I stood outside an auto wrecker’s yard and threw rocks into the yard over the fence,” he used to say, “I could stand there and throw rocks for a million years, and I’d never hear the sound of a car starting up on the other side of the fence.”
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