What if we took everything that
sustains life on this planet,
and shrunk it down to one small bubble?
Earth's biosphere stretches
about 20 km (12 mi).
From the deep-sea vents in the ocean
into the atmosphere.
This is where almost all life exists.
If we ever want to live in space,
or settle Mars,
we will have to recreate this
extremely complex system.
We’ve tried this once before,
with disastrous results.
In 1991,
eight scientists enclosed themselves
in a huge research facility called Biosphere 2.
This building was completely shut off
from the outside world.
All the food, air, and water
had to be produced and recycled
within its walls.
But the experiment quickly began to fail.
There was not enough food or oxygen,
the pollinators died,
and roaches infested this mini-Earth.
But could we do it again,
and this time, succeed?
The Earth’s biosphere is technically a closed system.
The only thing that enters the biosphere
is a continuous flow of energy from the Sun.
But creating an earthlike biome
is not as easy as it sounds.
Within Earth’s biosphere are biomes,
communities of flora and fauna that occupy
major types of habitats.
You’d need a collection of biomes
to create a successful,
life-supporting mini world.
Like Biosphere 2,
you'd be living in a 12,700 square meter (3.14 acre) facility,
which would contain a rainforest,
an ocean with a coral reef,
mangrove wetlands,
savanna grassland,
and a fog desert.
You would also need agricultural land,
and a place where you lived and performed laboratory work.
As for your daily routine,
it would be rough.
Keeping yourself alive
would be a lot of work.
You'd spend almost 35% of your time on agriculture.
Then there's all the maintenance,
lab work,
and household chores.
Your diet would be mainly vegetarian.
It takes at least 25% more water
to produce 1 kg (2.2 lb) of meat
than 1 kg (2.2 lb) of wheat.
Because animals require a lot of resources,
you’d carefully select which ones to bring into your biosphere.
I suggest the African pygmy goat,
the most productive domestic animal in Biosphere 2.
Its milk would be a welcome break
from all the vegetables you’d be eating.
The crew of Biosphere 2 survived
mostly on sweet potatoes and beets.
But you’d do a better job and successfully grow
a hundred different crops,
including papaya and rice.
Even with all your agricultural work,
starvation would be a real threat.
Because your biome is so small,
the slightest problem
can ruin your food crop.
You could have unbalanced soil composition from adding waste,
pollinators dying off,
pests increasing,
disease.
Whole fields of food could be ruined,
leaving you very hungry.
In the 1991 experiment,
working relentless hours and facing constant hunger
created rifts within the small community.
To avoid this,
you’d need the perfect number of people
to balance the other work and food production.
Too few people, and you’d be overworked.
Too many people, and there wouldn't
enough food to go around.
While crops would be a major focus of your attention,
you'd still need to
tend to the rest of the biomes.
Plants wouldn’t just be for eating, after all.
They’d also produce oxygen.
And much like the Amazon rainforest,
you’d need areas that are
full of plant life so you could breathe.
Too little oxygen, or carbon dioxide,
and you could be in trouble.
It’s tricky to balance them,
and in Biosphere 2,
oxygen depletion became a huge issue.
Why?
They mixed too much organic matter into the soil.
This caused an explosion of
oxygen eating microbes,
which decreased the amount of oxygen.
And the carbon dioxide produced
by these microbes
reacted to a chemical in the biosphere's concrete.
So the plants couldn't use the
extra carbon dioxide during photosynthesis.
Luckily, we learned from that mistake.
You'd make your biosphere so it wouldn't react to carbon dioxide.
So you have enough food and oxygen.
That’s good.
But what about waste?
It has to go somewhere,
and there's no room for
landfills in your mini world.
You’d have to compost all human and animal waste.
And remember,
this compost would increase the number of oxygen eating microbes,
so you'd need to plan for that while maintaining your biosphere.
Everything you use would be reusable,
and it would all have to be compostable.
You'd mend your clothing,
made out of cotton, silk, and wool,
many times.
Then you'd use it for rags,
then stuffing,
and finally you'd throw it on the compost heap.
You’d rely on technology to circulate air,
pump water,
and constantly measure everything in the biosphere.
This takes power.
And your only options would be solar,
nuclear,
or both.
Earth is a vast, complex system,
where every living organism,
including you and me,
are connected.
Recreating that,
on any scale,
is a gargantuan task.
And we’ll have to master this process
if we ever want to settle Mars,
or create cities on the Moon.
Want to learn more about living in a closed biosphere?
Join us on What If Discussed.
We talked with Jane Poynter,
one of the original eight members of Biosphere 2.
She'll tell us more about the biology,
the oxygen problem,
and the psychology
of living in a closed biosphere.