Energy and Human Ambitions on a Finite Planet, 2021a

18 <strong>Human</strong> Factors 312
18.4 Fermi Paradox Explained?
Having discussed some of the top-level challenges facing our technological
society, it is too tempting to speculate on how universal our trajectory
might be. We do so in the context of the Fermi Paradox [119], which asks:
if the universe produces a reasonably high probability of intelligent
life developing, why have we seen no credible evidence 32 of advanced
civilizations? Yes, this is a bit of a tangent, 33 but it could be interpreted
as a relevant data point in the likelihood that we maintain an advanced
civilization for a long duration.
The setup to the question is a “big if.” The usual approach to estimating
the number of intelligent species in our galaxy 34 is via the Drake Equation
[120]. The equation is simple, just multiplying the number of stars by
a chain of probabilities: that the star has planets at all; that one of the
star’s planets is “habitable;” that the environment is benign <strong>and</strong> that life
has had enough time to develop; <strong>and</strong> finally that the life develops into
an intelligent form, capable of communicating. Also factored in is the
likelihood that any such species would endeavor to reach out, <strong>and</strong> how
long their civilization lasts in that state so that we might overlap 35 in
time. For the Milky Way galaxy, 100 billion stars—almost all of which
we now know are likely to have planets—gives a huge start so that even
if the chance of intelligent life arising is one in a million, we’re left with
quite a margin.
But maybe our trajectory is pretty typical. By the time an intelligent
species arises, the many millions or billions of years of life leading
up to that event may ubiquitously lead to deposits of fossil fuels. 36
The first species smart enough to utilize the planet’s fossil fuels does
so with reckless ab<strong>and</strong>on. Because evolution does not skip steps, we
should not expect to find a species wise enough to refrain from rapid
fossil fuel use emerging before a species who is just smart enough to
use them, but not smart enough not to. So the “intelligent” species
short-circuits the battery 37 in a blaze of glory that may even involve
baby-step excursions into space before either climate change or other
resource/planetary limitations removes the fossil fuel source that made
it all possible. Lacking wisdom <strong>and</strong> foresight, solid plans are not in
place to h<strong>and</strong>le the withdrawal, which does not go well <strong>and</strong> leaves the
species in a crippled lower-tech state. Rebuilding from the ashes is then
much less likely to explode without that one-time elixir that made it all
possible the first time. 38 A simple, <strong>and</strong> possibly quite satisfying life may
await, but it may not involve traveling or communicating across space
for others to learn of our existence.
This notion is, of course, highly speculative <strong>and</strong> of little practical value.
Except it may allow us to think “bigger” than ourselves <strong>and</strong> ponder
whether it is surprising that we might fail to achieve a Star Trek future.
It is at least somewhat relevant to note that the universe we peer into
does not have an evident intergalactic intelligent presence. Perhaps the
32: ...in the form of communications or
alien visits
33: Normally, this kind of tangent might go
in a box, but it is big enough to be awkward
in that format, thus a whole section.
34: ...or the whole universe, if thinking
more broadly
35: The notion of “overlap” is complicated
here by the 100,000 light-year scale of the
galaxy, so that by the time a signal arrives
at Earth, the civilization may be long gone
already.
36: . . . buried remnants of life
37: Fossil fuels can be thought of as a solarcharged
battery that we are discharging
almost a million times faster than the time
it took to charge it: see Box 10.2 (p. 169).
38: Also, easily accessed surface metal deposits
have long disappeared, bringing into
question whether a Bronze Age would be
possible to replicate.
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.;
Freely available at: https://escholarship.org/uc/energy_ambitions.