“You mean like the shooting of Arch-
duke Franz Ferdinand?”
“1914. Franz Ferdinand was assassi-
nated by a fervent Yugoslavian national-
ist. Small event. But within months, they
were digging trenches in France. The
First World War.
“No trenches here, Lily. And no archdukes either.” He pulled the gate on the
pickup, and three tons of water spilled
out onto the parched earth.
In 20 minutes, Eliot was looking at
his difference plots. Despite the fact that
he had lowered the surface temperature
of his yard considerably more than the
five degrees of his numerical test, there
was still no apparent effect within 250
miles. This butterfly had flapped its
wings for naught.
What Eliot couldn’t see, and wouldn’t
understand until much later, was that six
hours after he flooded the yard, a Russian
military transport carrying diplomats
would run into trouble on its approach
to Warsaw’s Bemowo Airfield. The
flight forecast had predicted smooth
skies all the way. And they were, except
at 3,000 feet short of the runway where an
unusually forceful dust devil lifted one
wing and tossed the plane on its back.
Was it an accident? The Russians certainly didn’t think so. This was subtle
sabotage, and no degree of pleading
could convince them otherwise. In the
predawn skies the following day, an unmanned drone headed west, hugging
the flat landscapes of Northern Europe.
Someone had finally done something
about the weather.
Seth Shostak ( firstname.lastname@example.org) is the senior astronomer at
the SETI Institute in Mountain View, CA.
© 2017 ACM 0001-0782/17/11 $15.00
But now he considered a slightly
greater perturbation—not a butterfly’s
flutter but a disturbance as large as a
tennis court. A change in the parameters
of one cell in that mother of all spreadsheets. Could such a perturbation have a
significant effect anywhere else?
Eliot decided on an experiment. First,
he ran a model based on the latest grid
data—nothing new there—predicting
the weather 20 minutes into the future.
Then he went back into the input matrices and manipulated the parameters in
one cell, the one that covered his backyard. He then lowered the temperature
by five degrees and ran the model again.
A simple program subtracted the
two results, color-coding any differences. Blue indicated cells with no
change, green very slight differences,
and yellow and red locations that were
significantly altered. Because weather,
carried by the wind, doesn’t move faster than the speed of sound, he looked
at the results only within 250 miles.
Beyond that, Eliot would need a prediction further into the future, and
couldn’t be sure if any effects were due
to his manipulated data or not.
The difference plot was mostly just a
noisy sea of blue and green pixels. A few
were red, indicating, for example, the
barometric pressure was 1% greater or
lesser than it would have been without
the backyard temperature change. His
theoretical butterfly hadn’t had much
effect. But there was one spot that was
yellow . . . where the local wind speed
had increased by a factor of two. A factor
of two! Eliot pushed back his chair and
let out a low whistle.
Lily watched her husband inch the
rented pickup down the driveway, stopping just short of the desiccated wasteland that was their yard. He had lined its
bed with plastic and spent several hours
filling it with water from the kitchen
“Are you going to tell me what this is
about, Eliot? I mean, is this your idea of
“I’m going for a real live butterfly
“Like when you feel nervous? When
your tummy turns upside down?”
“Not at all. It’s when a small stimu-
lus produces a big effect. Consequences
that greatly outweigh causes.”
[CONTINUED FROM P. 101]
But there was
one spot that was
yellow . . . where
the local wind speed
by a factor of two.
A factor of two!
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