Hey, smart people,
Joe here.
Fact: earth is experiencing
climate change
at a scale and pace
never before seen
since our species
has been on the planet,
and we're causing it by pumping
more heat-trapping carbon
into the atmosphere than earth's
natural systems can take out.
Now fixing a problem
as massive as climate change
is going to take a ton
of different solutions,
but more and more people
are asking
if trees might be a big part
of the answer.
For the past
370 million years or so,
they've been
one of the major ways
earth sucks excess carbon
out of the atmosphere
and stores it away.
And along with green plants
and algae,
this natural technology
captures carbon better
and cheaper
than any human technology
we've come up with so far.
But can trees actually make
a big enough difference
in cleaning up our mess?
Or are we-- well,
barking up the wrong tree?
I'm going to dig
into three different ways
that trees might help
solve climate change:
planting a bunch more trees;
saving the trees
we've already got;
and whether the field
of synthetic biology
might give scientists the power
to hack photosynthesis
and make trees even better
at being trees.
[THEME MUSIC PLAYING]
(Describer) Title: It's Okay to Be Smart.
(Describer) Title: Planting More Trees.
If you were paying attention
to YouTube last year,
then you probably heard
about Team Trees,
a project created by MrBeast
with help from Mark Rober
to raise $20 million to plant
20 million trees by...
well, now-- 2020.
And they succeeded--
or really, all of us did.
We basically took over YouTube
with tree videos,
and to date, Team Trees
has raised over $21 million
to plant 21 million trees,
which is insanely awesome.
But the Team Trees team
made one thing very clear--
The 20 million trees
by 2020
isn't going
to cure climate change,
but it's a step
in the right direction.
So, like, what does 21 million
trees do for the climate?
Tom from the channel
Aspect Science
made a great video analyzing
how Team Trees works
that you should check out
for more details.
But long story short,
21 million trees
covers an area a lot less
than you'd think.
(Describer) Three Manhattans.
And according to researchers,
an area of new forest that size
can capture 4 million tons
of carbon dioxide
spread out over tens of years.
Considering that
the world emitted
more than 40 billion tons
of carbon dioxide in 2019,
we would have to do Team Trees
literally thousands of times
to plant enough trees
to suck it all up.
Sounds pretty impossible,
doesn't it?
Well, it might not be.
Meet Felix Finkbeiner.
Today we want to convince
the world
to plant a trillion trees.
That's roughly the number
of trees
we have space for, globally.
[JOE]
The seed for this idea
began when Felix
was in just fourth grade.
During a presentation
I was giving
about climate change
back then,
I had to tell my classmates
that we should plant
1 million trees
in each country of the world.
My classmates loved the idea.
They were super enthusiastic
about planting trees.
A few weeks later,
we planted our first tree
without really knowing
where we would go from there.
Two local journalists reported
about this first tree.
That's how some other schools
found out about it.
And that's when a real
competition kicked off--
who would plant
the most trees?
And that's how Plants
for the Planet spread.
[JOE]
A few years after
that class project,
Felix's group planted
its millionth tree
and he was invited
to tell his story
before the United Nations.
But for us children,
forests are our future.
[JOE]
There he met someone
very special.
By far, the most important
person in this story
was a woman called
Wangari Maathai from Kenya.
There are some people
who have changed the world
in incredible ways that
almost everyone knows about--
Gutenberg
and the printing press;
Albert Einstein
and relativity;
Jonas Salk
and the polio vaccine.
But there are others that,
for some reason,
we never learn about.
Wangari Maathai
is one of those people.
Maathai was
an African biologist
who had an idea.
[FELIX]
But one of
the most beautiful things
she did was she essentially
used tree planting
as not only a tool
for nature conservation,
but also
for women's empowerment.
When I was nine years old,
I heard about
this fantastic work,
but I didn't understand
the true depth of it.
I only understood
that tree planting
helps tackle
the climate crisis
and saves the polar bears.
[JOE]
She won the Nobel Peace Prize
for her work,
but few people know her name.
So what impact<i> would</i> planting
1 trillion trees have?
We used to have roughly
6 trillion trees on earth.
So this was before humans
starting cutting them down.
And now we have about
half of that remaining.
(Describer) Finkbeiner:
So we've got 3 trillion
instead of 6 trillion trees.
Ideally, we want to go back
to the 6 trillion, right?
Get back every tree we lost.
But of course we need space
for our settlements,
and much more for agriculture.
But we can get
about another 1 trillion back.
They wouldn't solve the climate
crisis on their own, of course.
We also need to drastically
reduce our global CO2 footprint.
But they make it possible
to ensure
that the global temperature
does not rise
by more than two degrees.
And if we manage
to plant these trees,
they would capture
about a quarter
of human-made CO2 emissions.
(Describer) Title: Stop Cutting Trees Down.
Remember, trees are basically
big carbon-storage machines
that suck CO2
out of the atmosphere
and turn it into more tree.
Cutting those trees down
and either burning them
or letting them decompose
just puts that carbon
back in the atmosphere.
Most deforestation happens
in earth's tropical regions.
If this tropical deforestation
were a country,
it would be the third biggest
emitter of carbon in the world
after China and the U.S.
Almost one-third of all
the world's carbon emissions
since 1850 have come
from deforestation.
These days, forests remove
about a quarter of the CO2
humans emit into
the atmosphere each year
and store it away.
There is more carbon locked up
in the world's trees
than in all the fossil fuels
still remaining in the ground.
And beyond carbon,
tropical forests
act sort of like
the planet's air conditioning.
They pull moisture
out of the ground,
release water vapor
into the sky,
and literally create
rain and weather patterns
across the globe.
Cutting down
these tropical forests
can raise nearby temperatures
by as much as 3 degrees Celsius.
So the point is,
keeping the trees we have
is essential if we want
to keep climate change
from getting even worse.
To put this challenge
into scale,
if Team Trees
gave us 21 million trees,
the 2019 Amazon wildfires
that took over social media
burned at least
1 billion trees.
And this year's
Australian bushfires
may have burned more
than 10 billion trees.
Luckily, protecting the trees
we already have
is cheaper and easier
than planting new ones.
But natural processes,
like photosynthesis,
on land and in the ocean,
are only absorbing
about half the CO2
that we currently emit
every year.
If you think of it like money,
we're spending more than we earn
in our carbon budget.
And many experts think
saving trees
<i>and</i> planting as many
new ones as we can
are both part of the answer.
There is one more idea
that can make a big difference,
and it relies on something
called synthetic biology.
(Describer) Title: Hacking Tree Biology
When plants like trees take
carbon dioxide out of the air,
they use
a tiny molecular machine
inside their cells
called an enzyme
to grab CO2, stick that carbon
onto another molecule,
and eventually make sugar.
This molecular machine's
name is a mouthful:
ribulose-1,5-bisphosphate
carboxylase oxygenase.
But you can just call it
RuBisCO for short.
Just about everything on earth
that does photosynthesis--
algae, cyanobacteria,
grass, trees, you name it--
uses RuBisCO to grab carbon
out of the air.
Scientists think it's the most
abundant enzyme on earth.
This little
molecular machine
has completely
reshaped our planet.
The problem is, RuBisCO
isn't very good at its job.
Many molecular enzyme machines
can carry out thousands
of chemical reactions
in a single second.
RuBisCO is super slow.
It can only grab five to ten
CO2s every second.
And about one
out of every five times,
RuBisCO grabs
the wrong molecule--
oxygen instead of CO2.
It just wastes energy
in the process.
If we could make
this biological chemistry
work better and faster,
maybe we could pull
even more carbon
out of the atmosphere.
Some scientists
have put genes for RuBisCO
inside bacteria in an effort
to rapidly evolve
a more efficient enzyme.
By manipulating
the genetic sequence
in the DNA code
for the enzyme,
researchers can make
many, many more versions
of RuBisCO than nature can
on its own.
And perhaps one will be faster
and more efficient
at grabbing carbon
out of the sky.
Other researchers are digging
through the enormous toolbox
of chemical reactions
that exists in nature
to look for totally new ways
to capture carbon.
These researchers start
by designing
a highly efficient
chemical reaction on paper,
then plugging in individual
molecular machines
from different species
in order to build
the chemical process
from scratch.
These are pathways
that don't exist in nature
built almost like Legos
by combining different
molecular machines
that do exist.
But even if scientists
do figure out a way to improve
on biological chemistry,
we can't instantly go upgrade
every photosynthetic organism
on earth,
including trees.
But it might give us
a new way of capturing carbon
using biological reactors
in places
where emissions are high
or even linked to devices
capable of artificial
photosynthesis that can work
alongside the trees
and plants we already have.
Unfortunately, it will take
decades of research
to engineer
these molecular machines
to be even close to what
nature can already do today
using low-tech,
carbon-sucking,
light-eating machines
like trees.
Trees are a solution
we already have.
But as I hope
you've realized by now,
even if we saved every tree
that already exists,
and even if we planted trees
in every spot on earth
that could hold them,
we still wouldn't be absorbing
all the climate-changing carbon
that we emit each year.
The bottom line is this:
no matter what climate-change
solution we're talking about,
whether it's trees
or electric cars
or next-generation
nuclear reactors
or synthetic meat,
none of it will work
unless we stop putting
so many greenhouse gases
into the atmosphere.
It's really that simple.
Solving climate change
isn't just about what we do,
it's about
what we stop doing too.
Stay curious.