Narrator: As far as supervillains go,
Thanos is, well, not very bright.
Say what you will about Doc Ock,
Syndrome, or Lex Luthor.
At least they put considerable
scientific thought behind their evil plans.
Nanowires feed directly into my cerebellum.
Narrator: Meanwhile, check out Thanos' master plan.
The entire time I knew Thanos,
he only ever had one goal:
to bring balance to the universe
by wiping out half of all life.
Narrator: Yeah, this scheme to conserve resources
by eliminating half of all life makes no sense.
In fact, it wouldn't save the planet.
It would doom it.
Let's start with his decision to wipe out half of humanity.
Now at first, you can see his reasoning.
After all, there are 7.7 billion humans on the planet today.
That's nearly 7% of all the people
who have ever lived in the history of our species,
which makes for a pretty crowded planet.
So if half of us suddenly vanished,
wouldn't that be a worthy sacrifice?
No. Ethics aside, we'd still be left
with almost 3.9 billion people,
about the same world population in 1972.
So if history repeats itself,
it would buy us less than 50 years
before we reached current levels again,
and the same is true for many animal species
like deer, whose healthy populations
would help them rebound quickly.
But unfortunately, the same can't be said
for endangered species who have the opposite problem.
Take the critically endangered Sumatran tiger, for example.
Experts estimate there are fewer
than 400 left on the planet.
If half disappeared, there wouldn't be
enough to sustain the population,
and they would likely go extinct,
and endangered sharks, hawks, and leopards
would probably meet the same fate,
and that's where Thanos' plan to save
the world really falls apart.
Once a top predator disappears,
they can take the rest of their ecosystem down with them.
Take gray wolves for example.
The US government eradicated them
from Yellowstone in the 20th century.
With the wolves gone, the elk population
exploded and devoured the local vegetation,
which disrupted the population of
beavers, birds, and other species
that relied on those plants to survive,
and it gets even worse once you consider
that half of every plant species on Earth is gone too
because just like with animals,
there are thousands of endangered plant species,
many of which are too vulnerable
to survive Thanos' plot,
and if plant species die out,
the rest of their food chain would starve.
Of course, many plant populations aren't endangered,
but even that won't save them all in the long run.
You see, scientists estimate that 90% of all
flowering plants depend on animals to reproduce,
but Thanos wiped out half of all
bees, fruit bats, and every other pollinator on the planet,
many of which are already in trouble.
For example, 50% of bee species in the Midwest
have vanished in the past century,
and the lesser long-nosed bat,
a key pollinator in the Sonoran desert,
is also disappearing,
so they would probably die off completely,
and if enough pollinators go poof,
we're looking at a possible total ecological collapse.
So while Thanos' plan wouldn't
directly devastate thriving species,
the chain reaction that could come
from eliminating endangered species
could really mess things up for everyone else left alive.
No resurrections this time.
Narrator: Nice going, Thanos.
To be fair, the planet has experienced
mass extinctions before, and life recovered.
For example, an asteroid strike 66 million years ago
wiped out 75% of all species on Earth,
and with the dinosaurs out of the way,
our mammalian ancestors flourished.
But even so, experts estimate it takes
around 20 million to 30 million years
to recover from a mass extinction.
So unless waiting around for millennia
was all part of the plan,
the Mad Titan messed up, big time.