Cloudy With a Chance of War: His weather forecasts changed the world. Could his predictions of war?
From Nautilus:
The burial detail, which had come for the corpses in the pigpen, was surprised. The “dead” were getting up and speaking English. Qu’est-ce que c’est?
Ah, they were an ambulance crew. British volunteers, in the trenches
with the French Army on the Western Front. In the ruins and wreckage
near the front lines, they’d found nowhere else to sleep.
The
medical corpsmen were all pacifists, serving humanity even as they
refused to serve in any military. Still, they lived like the troops.
They bunked in rat-infested dugouts, on the floors of shelled buildings,
in hay-filled barns. They dove for cover when incoming shells moaned
and screamed, and struggled with their masks when the enemy fired gas
canisters. At any moment, they could be called to go to the front lines,
gather wounded men, and drive—lights off on roads cratered by shells,
packed with trucks and troops, with every jostle making the blood-soaked
soldiers in the back cry out in pain—to a hospital.
It was the
last place in the world to look for a scientist at work. Yet one
soft-spoken corpsman, known as “Prof,” filled his downtime with
experiments and calculations. “We thought nothing of seeing him
wandering about in the small hours checking his instruments,” one of his
fellow corpsmen recalled. Once, for example, he’d set a bowl of water
on a record-player he had somehow got hold of, cranked up the machine,
and measured the radius of the curve on the water’s surface. A rotating
fluid, he thought, might serve as a useful model of the atmosphere.
(Though his record player wasn’t up to the task, later work would prove
him right.)
“Prof” was the English physicist and mathematician
Lewis Fry Richardson, for whom doing science came as naturally as
breathing. “It was just the way he looked at the world,” recalls his
great-nephew, Lord Julian Hunt. “He was always questioning. Everything
was an experiment.” Even at the age of 4, recounts his biographer Oliver
Ashford in Prophet or Professor? Life and Work of Lewis Fry Richardson,
the young Lewis had been prone to empiricism: Told that putting money
in the bank would “make it grow,” he’d buried some coins in a bank of
dirt. (Results: Negative.) In 1912, the now-grown Richardson had reacted
to news of the Titanic’s sinking by setting out in a rowboat with a
horn and an umbrella to test how ships might use directed blasts of
noise to detect icebergs in fog. (Onlookers might have shaken their
heads, but Richardson later won a patent for the fruit of that day’s
work.) Nothing—not fellow scientists’ incomprehension, the distractions
of teaching, or even an artillery bombardment—could dissuade him when,
as he once put it, “a beautiful theory held me in its thrall.”
In 1916, two beautiful ideas gripped Richardson’s attention.
At the heart of both was the complex interplay of predictability and
randomness that is turbulence.
His first idea was rooted in his
principles as a Quaker pacifist who believed “science should be
subordinate to morals.” Everyone spoke of this Great War as if it had
been a catastrophic surprise. Who could predict a lone assassin in
Sarajevo? Or that the belligerents would not find a way to defuse the
crisis, as they had before? Or that plans for a quick victory would sour
into this stalemate in the trenches? War, Richardson thought, far from
being an unforeseeable accident, might instead be the consequence of
as-yet-unknown laws operating on measurable facts. Beneath its seemingly
random and chaotic course were the regular patterns of these laws. With
the right data and the right equations war might be predictable—and
thus preventable. He believed that humanity could some day avoid war as
ships could some day avoid hidden icebergs.
Whenever he could, in
quiet moments or when his ambulance corps was rotated to the rear for a
rest, Richardson worked on a long paper on “the mathematical psychology
of war.” (“I remember him telling me, ‘let x be the will to hate,’ ” recalled one of his less equation-oriented friends in the unit. “It beat me!”)
But
it was Richardson’s other great idea that would come to fruition first,
and make him famous. In fact, after many decades of obscurity it would
come to be appreciated as one of the most significant technologies of
the 20th century. At the front lines, and in the rest billets where the
corps was rotated out for a break every few weeks, Richardson was
looking for a way to forecast the weather.
At
the turn of the last century, the notion that the laws of physics could
be used to predict weather was a tantalizing new idea. The general
idea—model the current state of the weather, then apply the laws of
physics to calculate its future state—had been described by the
pioneering Norwegian meteorologist Vilhelm Bjerknes. In principle,
Bjerkens held, good data could be plugged into equations that described
changes in air pressure, temperature, density, humidity, and wind
velocity. In practice, however, the turbulence of the atmosphere made
the relationships among these variables so shifty and complicated that
the relevant equations could not be solved. The mathematics required to
produce even an initial description of the atmosphere over a region
(what Bjerknes called the “diagnostic” step) were massively difficult.
To get a forecast without stumbling on the impossible calculus of the
differential equations, Bjerknes represented atmospheric changes using
charts. For example, as the historian Frederik Nebeker explains in Calculating the Weather: Meteorology in the 20th Century,
the chart might show more air flowing horizontally into a region than
out, allowing the forecaster to predict that the remainder of the
incoming air is flowing upwards in the form of vertical winds.
As
it happened, since Richardson’s graduation from Cambridge in 1903, he
had confronted similarly difficult equations as he moved restlessly
among posts in academia and industry. Analyzing stresses in dams and the
flow of water through peat, he had developed a different work-around.
Only
differential equations, with their infinitely small quantities changing
over infinitely small units of time, described the continuous change he
wanted to model. But since those equations couldn’t be solved,
Richardson reworked the math to replace the infinitesimals of calculus
with discrete measurements occurring at discrete time intervals. Like a
series of snapshots of a ball flying through the air, Richardson’s
“finite difference” equations only approximated the reality of the
constant change they described. But they could be solved, with simple
algebra or even arithmetic. And their solutions would be far more
precise than any obtained with a chart....MUCH MORE
