by Susan Casey
When you consider the overwhelming complexity of the ocean and the atmosphere, it’s not hard to understand why. It seems futile to try to model things so immense and so inherently random. To science’s deep frustration, nature regularly confounds our attempts to predict its next move. When I’d asked Don Resio whether he thought climate change would lead to stormier oceans and bigger waves, he shrugged dramatically. “We can’t predict ten days out,” he said. “What makes us think we can predict ten years into the future?” At the same time—because we need whatever intelligence we can gather about the natural world in order to live in it and build things in it and hope to understand it—there’s nothing to do but try. So the sessions continued, and people leaned over their laptops and tried not to notice through the windows that playing in the waves looked like a whole lot more fun than writing equations about them.
Driving from another part of the island, I got wildly lost on my way back to Turtle Bay and ended up tiptoeing into the Climate Change session, midpresentation. The first words I heard were: “There is high uncertainty here.” Given what the scientists had been saying, this sentence seemed to sum things up perfectly. The next talk was about whether the waves were getting surlier in northern latitudes (yes), and what this might mean for ship navigation (trouble); followed by a consideration of how climate will affect hurricane frequency (we’re not sure) and storm surges (pass the sandbags); all of which provoked heated discussion. During one presentation Zakharov, wearing a scarlet Hawaiian shirt, stood up and unleashed such a torrent of protest that Resio cut in: “Is there a question in there, Vladimir?”
Later in the day, during a talk about storm surge behavior, Resio mentioned Hurricane Katrina. As a Southerner he took that storm personally, and when he spoke of its terrible impact, his voice tightened and his eyes became grave. “When there’s a wave event at the coast we always underpredict,” he said, then paused. “Katrina was a wakeup call. We don’t have the science that we as a nation need.”
At the break I went outside, where I ran into Dave Levinson and John Marra, another scientist. Marra, who lived on Oahu, had longish hair and an athletic build, and he revealed himself as a surfer by staring at the nearby waves the way a cat stares at birds. When Levinson introduced me and described my project, Marra had a question. “Those guys who want to launch their melons off a hundred-foot wave,” he said, “are they mentally ill?”
“Does that mean you think it can’t be done?” I asked.
“I don’t know the phase speed of a hundred-foot wave,” he said, turning serious in an instant and citing advanced math theory about breaking waves. “I’d have to actually calculate the celerity. I don’t see why not, I guess—if you’re moving fast enough. But is it human nature to want to do that?”
I defended the tow surfers’ sanity for a few moments, then steered the subject to climate change. Like Levinson, Marra was not investing in coastal real estate anytime soon. His opinion was grim. “The polar zones are done,” he said, with finality. “And there are going to be basic survival issues like no water. Ecosystem collapses. Food chain—”
“There’s no question you’re right, John,” Levinson said, interrupting. “The water issue’s going to be the worst.”
“Then what’s with all the arguing in there?” I said. “Why don’t scientists agree about this stuff?”
“Well, it’s natural variability versus human influence,” Levinson said, explaining how science had to discern which changes could be chalked up to nature’s regular cycles, and which were due to our monkeying around with the planet’s chemistry: “The record is so short that the naysayers can point to uncertainty in the attribution of climate change.” You couldn’t pin any single event on climate change, or even a few years of wacky weather: you had to examine longer-term trends. Which, of course, takes time.
Marra jumped in. “Dave’s point is that you’re not going to be able to prove it until it’s too late. It’s the frog-in-the-pot analogy. He doesn’t know he’s cooked until it’s too late and he is cooked.”
Levinson nodded. “Uncertainty doesn’t mean it’s not happening.”
“I really wouldn’t want to be a weather forecaster right now,” Marra added, “because we’re entering into a time when, possibly, there is no normal anymore.” He smiled, shaking off the gloom. “But that’s all the more reason to surf! Go grab a couple of those total ‘now’ moments, because that’s all there’s gonna be anyway.”
I caught up with Al Osborne at the conference luau. Tables had been arranged on a bluff, backed by a silky pink sunset. The surf was still hopping. When the moon came up, tiki torches were lit and the wave crests flared in the background. A Hawaiian band took the stage, the singer leaning into the microphone: “Now, some hula for you wave junkies!” Osborne was sitting next to Resio, and I went over to join their table.
Osborne was nursing a head cold and some terrific jet lag, but he was still game to talk about waves. Actually, the subject seemed to perk him up. “All physical phenomena are waves,” he said, with a hint of Texas drawl. He jammed his hands in his pockets, leaned back in his chair, and nodded toward the sky. “The universe is constructed of waves. And let me tell you why. It’s craziness!”
From the start of his career, Osborne had a knack for running into the strangest waves. Trained as a cosmic ray physicist, he left NASA’s Apollo program in Houston to work in Exxon’s oceanography group. It was the early 1970s, and oil exploration was heating up. To safely drill in the ocean, companies like Exxon desperately needed science expertise. Osborne had this—for space. “When I first went to work there [Exxon] I didn’t know anything about [ocean] waves,” he said. “I mean anything. And water waves are more complicated than electromagnetic waves because they’re nonlinear.”
But he was a quick study and a curious guy, and when Exxon sent him on a critical assignment in the Andaman Sea, Osborne was more concerned by the State Department’s warning that the area was inhabited by “implacably hostile headhunters” than any professional shortcomings. His job was to find out why the Discover 534, the world’s biggest drill ship at the time, was getting boxed around in what seemed like calm seas. “Nobody had ever made any measurements there,” Osborne said. “Nobody knew.” Using jury-rigged instruments and an unintentionally expensive trial-and-error approach, Osborne solved the mystery. To his shock, he found that two hundred yards below the ship, gargantuan underwater waves more than six hundred feet high and ten miles long were rumbling by at a speed of four knots. Nothing in the model explained this. “It was just stuff that shouldn’t have been there,” Osborne recalled. “So I learned about internal waves.”
We now know that internal waves are basic features of the ocean, visible on photographs taken from space. Water densities vary in any patch of sea, sort of like a layered cocktail. When tidal forces drag one layer over another, internal waves are born. They play a critical role in ocean circulation (and thus, climate) and move nutrients throughout the water column. And they have an additional characteristic that fascinated Osborne: they’re solitons, waves that behave like particles.
Solitons have long been causing wave scientists to scratch their heads in bewilderment. In 1834 a Scottish engineer named John Scott Russell happened to see an odd wave moving through a canal near Edinburgh. Describing it as a “rounded, smooth, and well-defined heap of water,” he followed the wave on horseback for two miles as it cut through the canal like a shark’s fin, rather than oscillating up and down like a normal wave. “It rolled forward with great velocity,” he wrote, “without change of form or diminution of speed. How could this be?”
The vision of a singular, misbehaving lump of water blew Russell’s analytical mind. The wave, which he called the “Great Wave of Translation,” seemed to defy Newton’s laws of hydrodynamics (which consider fluids to be continuous fields rather than a parade of discrete objects). The Great Wave would obsess Russell for the rest of his life, and when he failed to convince other scientists of wha
t he had seen, it ruined his career. It was only when quantum physics came along seventy years later and explained the soliton—how one wave could behave independently from, and be unaffected by, the waves around it—that Russell was vindicated.
As it happens, solitons exist anywhere there is wave motion: in gases, in telephone signals, in the sky, even in our bodies. But in 1975 for Osborne to find them lurking in the ocean was such a scientific coup that he ended up on The Tonight Show with Johnny Carson.
“I couldn’t stand prosperity,” Osborne said wryly, recalling those years. “So I moved to Italy.” At the University of Turin he continued to study waves, examining their quantum underpinnings. In 1999 a graph depicting the Draupner freak wave spiking out of the ocean stopped him in his tracks. It looked exactly like a soliton. Therefore, his mind sped ahead, it should be possible to create freak waves using the nonlinear Schrödinger equation (a famous breakthrough in quantum physics that described this kind of renegade wave behavior by electrons).
Sure enough, in the wave tank Osborne was able to dial in Schrödinger and make tiny freak waves jump out of the water. “After hundreds of years of everything about freak waves being based on anecdotal evidence,” Osborne said, “suddenly there was a real physical dynamic.” While freak waves are not solitons exactly—the two are more like second cousins—the point he made was important: when you veered off the linear path into the dark, nonlinear woods, you came closer to understanding the ocean at its most extreme. (Since then tsunamis have also been identified as soliton kin.)
The longer I listened the more it seemed that Osborne’s discoveries supported the scientific adage that “the universe is not only stranger than we imagine, it is stranger than we can imagine.” When talking about his work, Osborne used phrases like “black magic” and “utter miracles,” which would seem to make for a pretty exciting day at the office. In light of this I had one last question, a fairly preposterous one. Earlier he had mentioned that in order to come into being, a rogue wave had to mug (my description) its neighbors. After attempting to explain this to me using the Benjamin-Feir instability theory, the Reimann Theta functions, and Fourier analysis, Osborne finally broke down and personified the waves like sock puppets. “It’s like this rogue wave is hiding,” he said, using his hands to demonstrate. “He’s got his arms out, covering a lot of other waves. And when he gets ready, he sweeps in all their energy, stealing it from them and pulling it up under this one big single peak.”
Since I am not a scientist, the image of rogue waves as clever oceanic criminals delighted me and stuck in my mind. But what made one wave a perpetrator of this energy theft, and another a victim? It was almost as if some kind of ghostly, esoteric intelligence were involved. “I don’t think you can call it intelligence,” Osborne said quickly. “Intelligence implies that you can plot and scheme. That requires a brain.” He paused for a moment and grinned. “But they do kind of play these games, don’t they?”
The Extreme Wave session came on the fourth day. Though I’d expected some heavy beach attrition by then, it was a packed house. The first presenter was Luigi Cavaleri, an animated Italian in his sixties, with fiery eyes and a mellifluous accent. Cavaleri’s talk was a cautionary tale about an exceptional—and completely unforecast—storm that had walloped Venice in 1966, the worst deluge in that city’s history. If such a thing were to happen today, Cavaleri wanted to know, would we be able to predict it?
It was impossible not to like Cavaleri, a whip-smart man in a no-nonsense plaid shirt, his sleeves rolled up, his caterpillar eyebrows jumping around on his face, his hands swimming through the air. “How many of you have seen the sea from below in a storm?” he asked. “It’s a completely different picture.” There was a murmur of polite laughter: as if. Almost every wave scientist I’d spoken to had confessed a preference for land, admitting to ravaging seasickness and a distaste for getting batted around at sea when the real work took place in front of a computer. Though Cavaleri’s research had revealed that, yes, we would probably be able to predict the storm now, his gentle reminder that it wouldn’t hurt for wave scientists to actually spend some time in the waves was what struck me the most about his talk.
In this regard the surfers had an advantage when it came to understanding the most extreme seas. Feeling a seventy-foot wave rising beneath your feet, hearing its turbine roar, pulling three G’s on its face, and then dancing away from the blast—all of this, while not the type of fieldwork that’ll win you a Nobel Prize, is at the very least an informative experience. I had noticed that any tow surfer worth his foot straps was also a closet meteorologist, able to translate buoy readings, spectral analyses, swell periods, wind directions, and bottom features into the waves that would likely result. Many times Hamilton had surprised me by holding forth about things like wave refraction and dispersion, and Kalama had such a knack for interpreting storm data that he’d been nicknamed Decimal Dave. Perhaps there was an extra incentive to fathom the waves when your life, as well as your paycheck, depended on it.
A sandy-haired, studious-looking man named Johannes Gemmrich followed Cavaleri with a presentation titled “Are ‘Unexpected’ Waves as Important as Rogue Waves?” Unexpected waves, he explained, were super-size normal waves that happened along, up to twice as big as the average. More common and less mysterious than purebred rogue waves—which could reach heights more than four times greater than the surrounding seas—they could be equally destructive. Gemmrich showed slides of a trail on Vancouver Island where unexpected waves (sometimes referred to by sailors as sneaker waves) regularly sucked hikers off the rocks to their deaths. “Unexpected waves are not rogue waves,” Gemmrich said. “And not every rogue wave is unexpected.” I wondered how important the distinction was when you were being swept away by one.
Peter Janssen was up next, and he unfolded his tall, wiry frame from his chair and strode to the podium. He had wild gray hair, a peppery beard, and a strict, professorial appearance that seemed intimidating until you noticed the sparkle in his eyes. His talk concerned the second-generation version of ECMWF’s freak-wave warning system, soon to be launched. He stood at the screen with one hand in his pocket and the other gesturing to a mash of numbers, Greek letters, symbols, dots, slashes, and square-root signs. In the most rudimentary way I could follow him, because along with the very fast machinery that was whirring in Janssen’s head, he had a gift for being able to translate arcane wave science into plain English—even though English was his fourth language.
The previous day we’d met for a poolside lunch to talk about the warning system. “How can you possibly predict a rogue wave?” I asked. It seemed like a contradiction. “I prefer the term freak waves,” Janssen said. “Rogue waves—I’m always thinking of a herd of elephants.” He laughed and took a swig of Longboard Island Lager.
In his precise Dutch accent Janssen explained that in certain conditions, freak waves became far more likely to occur. The trick was to forecast those conditions. Surprisingly, the main criterion was not huge seas (although that helped) but rather the shape of the wave spectrum—the measure of how wave energy was distributed in a given area. It came down to steepness. Steep waves were farther from equilibrium: less stable, more prone to pirating other waves’ energy. If the spectrum was narrow and peaky—as if someone had taken some lovely, rolling waves and squeezed them hard in a vise—that was when, as Janssen put it, “you get a very high probability of extreme events.”
Fast-growing storms tended to create steep waves, as did high winds that blew for a long time in the same direction the waves were traveling. There were also infamous freak wave haunts like the Agulhas Current off the southeastern coast of Africa, where fast, warm currents collided head-on into colder, opposing currents, creating an oceanic train wreck. Again, this steepened the waves and deepened the troughs between them.
The ECMWF’s method of predicting freak-wave probability involved dicing the seas into forty-by-forty-kilometer squares, setting a baseline, feeding ocean a
nd atmospheric readings into the model, and then sounding the alarm when conditions looked suspect in any of the squares. In theory this sounds like a simple enough thing to do; in practice it is diabolically hard. How do you check to make sure your models are on the right track? At any given time, the oceans are mostly empty and unsurveyed, no one reporting back any excessively steep wave sightings. “It’s difficult to validate our theories,” Janssen said. “I am hoping to find satellite instruments that will be able to monitor those extreme situations.” He shrugged. “It might be that we are completely wrong.”
I asked Janssen the question I’d asked many other scientists: Should we expect more aggressive waves due to climate change? Like all of them, he hesitated before answering. “Wellll, what we see at the moment, yesss,” he said, drawing the words out carefully. During an earlier session, he noted, Russian scientist Sergey Gulev had presented a paper showing that wave steepness had increased sharply between 1970 and 2006.
“Climate change is not easy,” Janssen added. “Because in the early days we had hardly any data.” It’s tough to say there are more giant waves now—or hurricanes or windstorms—if no one knows how many there were before. Yet at this point few scientists believe there is nothing to worry about. “I can tell you one thing with climate change,” Janssen said. “I am quite sure that it is happening.”
It was November 2007, the tail end of an odd and tempestuous year. Huge waves had pummeled Europe, South Africa, Indonesia, China, Taiwan, and Australia, generating headlines like “Residents Flee After Waves Batter Indonesia’s Coastline,” “Asian Beaches Reopen After Winds Trigger Huge Waves,” and “Giant Waves Thrash Reunion Island.”
“Ireland Braced for Giant Waves: Massive waves higher than houses are expected to lash Ireland’s west coast this weekend,” warned the Edinburgh News, prompting one online reader to complain: “ ‘Waves higher than houses’—what kind of warning is that? Is that great muckle sky-scraping houses, or wee tottie tattie-pickers’ houses? We need to be told!”
