- Here's something weird.
All the coal in the world was made at the same time.
It was all made
during one brief period of geological history.
It started abruptly 360 million years ago
and it stopped abruptly 300 million years ago.
Like if you drill a hole into the ground
you'll pass through geological layers or strata.
It's like traveling back in time
and eventually you'll reach the coal strata.
And that strata is in the same position
everywhere around the world
because all the coal in the world was made at the same time.
But why?
Well to understand,
you need to know about the nutrient cycle.
Plants pull nutrients from the soil and from the air
and combine them into larger molecules
that they use to live.
And then when plants die they decompose.
Those larger molecules break down into smaller molecules,
and those nutrients are returned
to the soil so that new plants can grow and use them.
Except that plants can't decompose on their own.
You need to bring in these decomposers
basically fungi and bacteria that are good
at breaking down these larger structures
into small nutritious pieces that return to the soil.
And they derive some energy from that
and that's how they live.
So that's the nutrients cycle.
So let's go way back in time
to a period before there were trees.
So there were plants, but there weren't trees yet.
And some plant comes along that figures out or invents
throughout through the process and anthropomorphizing
but through the process of evolution,
they come up with the ability
to make some molecules called lignans
and lignans are revolution.
They're amazing.
They're these structural molecules.
They're the molecules that give trees their strength.
It's the essence of wood.
And they confer an amazing advantage
on the plants that can produce lignans.
And so this ability spreads all
around the world really quickly,
suddenly you've got woody plants and trees everywhere.
It's actually quite a good analogy
for the human invention of plastic.
It's like, "Wow, this is amazing.
Let's just put it in everything."
And then, "Oh my God, why won't it go away?"
So these lignans are novel.
Nothing has been seen like it before on earth.
And it's novel to the fungi and bacteria as well.
They've never seen anything like it.
They don't know how to decompose it.
So these new trees
when they die and fall over, they just lie there.
The bacteria and the fungi look at it.
I don't know what to do with these lignans.
Never seen it before.
And so these dead trees just pile up on top of each other.
They get squished.
It sticks around for long enough undecomposed
by fungi and bacteria that don't know what to do with it,
that it turns into fossils.
It turns into coal.
And then 60 million years later some bacteria or fungus
figures out, through the process of evolution,
how to break down lignans.
And again, it's a revolution.
It confers an amazing advantage onto the bacteria
and fungi that can do it because it's a new source of food.
So it spreads like wildfire around the world
and essentially cuts off the production of coal.
Is probably my favorite example
of the way that the geological layers
of the earth can tell us interesting stories
about our ancient history.
But here's a related question.
Where does a tree come from?
Like where does the mass of a tree come from?
And you might think, well, trees grow out of the ground
so the mass of a tree is slowly pulled out of the ground
as it grows, but that's not true.
Like a tiny bit of the mass of a tree comes from the ground
but most of it comes from the air
because most of the tree is made of carbon.
So trees draw carbon dioxide through their leaves
and it pulls the carbon dioxide molecules apart separates
into carbon and oxygen.
It holds onto the carbon.
It adds it to the structure of its body
and it releases the oxygen as a gas.
And that process is driven by energy from the sun.
So in a sense,
a tree is locking up solar energy into those carbon bonds
by separating the carbon from oxygen.
And that's why coal is such an effective fuel
because if you want to release that locked up solar energy
all you have to do is reunite the carbon inside
with the oxygen in the air
that it was separated from in the first place.
And that's what we do.
We burn coal to produce carbon dioxide.
And that's a problem.
We know this carbon dioxide is a greenhouse gas
and climate change is a real problem.
So what do we do?
Well, we can,
and I believe we should try to reduce the amount
of carbon dioxide that we produce.
But maybe at the same time
we should be looking at ways to draw carbon dioxide
out of the air in the way that trees do.
In fact, maybe we should be planting trees
so that they can pull the carbon dioxide
out of the air for us,
except that we're not doing that.
We're cutting down more trees than we plant.
This is just a short video.
It doesn't have a sponsor
but there is something personally really important
to me that I want to tell you about.
It's about the largest YouTube collaboration in history
and I'm really proud to be a part of it.
It's all about planting trees
and there's loads of other YouTubers involved.
In fact, it's probably
isn't the first time you're hearing this message
because all these videos are coming
out at exactly the same time.
The goal is to plant 20 million trees.
It's called Team Trees.
Each tree costs a dollar, so we need to raise $20 million.
It's a crazy idea, but I think it's possible.
I wanted to get involved
because I wanted to add my voice to the chorus.
But also I thought
if I could tell an interesting science story
that might be persuasive.
If you think you can give that's amazing.
The link is in the description is TeamTrees.org.
There's also a donate button there as well
to make it super easy.
Any amount that you can give is really appreciated.
All the ad revenue that comes to me
from this video will go straight to Team Trees as well.
If you feel like you can't donate, that's okay.
Maybe you think about spreading the word a little bit.
I think this is achievable
and what an amazing thing to be part of.
I hope you want to be part of it too.
I hope you enjoyed this video.
If you did, don't forget to donate
and I'll see you next time.
(upbeat music)