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The typical data
collection that happens on
a natural hazard or
natural disaster site is
these damaged records
that give some idea of
how many people died or
how much monetary losses we had
in a certain year in
a certain country.
Whereas we know that many of
these events do not take place
at the level of a country,
say the United States.
Even a disaster that we will
talk about in a few minutes,
that would be
Hurricane Katrina, was
a large, catastrophic
disaster that happened
in the United States but it
really happened at
the coastline of
Louisiana and Mississippi and
specifically New Orleans City.
Whereas for the entirety of
the United States in the work
by our Erik Strobl in 2012,
we know that this event did not
even become visible
in the national GDP,
for example, of
the United States.
We know that the
events that take place
and the impacts that
they result in,
they take place at
a different level
than the national level.
We need to zoom in, but this
is typically very hard because
national economic data come at
typically the national level
collected by census bureaus,
statistical bureaus that
collect these and put
them together to form, for
example, gross domestic product.
But if we want to look
at these impacts,
economic impacts
at a local level,
we would need some
similar measure but then
at the spatial scale of
the disaster, really.
In high-income
countries that might
be available, but in
many middle and
low-income countries,
these granular economic
statistics are simply not
available and if they are,
their quality is heavily
debated in the
economic literature.
We need a way to measure
the local economy.
If there's no data available,
that would be very
hard but there is
a large literature in
economics that has looked
into basically a new method
of doing this by proxying
local economic activity by
the use of nighttime lights.
These are remotely sensed
light emissions that are
emitted by humans and we
should say by people
and their economies.
They are captured by
satellites from space and
the intensity tells
us a lot about
the number of people that
are in a certain place,
but also the level of economic
activity that is in a place.
In a picture of
Northern America,
we can make some interesting
observations already just by
looking at a simple
picture of nightlights.
We know that the East Coast of
the United States is
heavily populated,
whereas it is much less so in
the center of the country and at
the West Coast we have
California lighting up brightly.
We can clearly see
from the pictures of
nightlights that lights
are bright where
economies are booming and are
big and this relation
between nightlife and
economic activity is
what we have taken
to the study of
natural disasters.
We started this project,
6-7 years ago
at the time of
recording this talk.
We were not the only
ones, of course.
Eric Strobl has
done a lot of work
in this and there are
other authors that have
contributed to this
literature as our research
expanded, and all are making
use of the same basic idea.
A natural disaster takes place
in a certain location where
it negatively affects
economic activity in the
short run with the hypothesis
that nightlights should
reflect this shock locally.
Indeed, many papers that
have been published over
the past years established
this correlation.
To dive into that
a little deeper,
to give you a touch of what
that should look like,
we will look into a case study.
