if you are good at empathising with other people,

this week's guest video may make you feel short of breath.

Seriously.

With that out of the way, let me introduce you to Kurtis Baute,

filming from inside his homemade, airtight biodome.

Kurtis, good luck.

- [takes breath]

Just over eight hours ago, I sealed myself inside of this cube.

It is 10 feet by 10 feet by 10 feet,

holds roughly 30,000 litres of air.

I'm gonna try to make this as short and sweet as I can

because with every breath that I take I am exhaling carbon dioxide,

and it is toxic at high enough levels.

Right now, it's at 6,370 parts per million.

[takes breath]

But to explain what that really means, I'm gonna have to step back a second.

Okay, I built this airtight, plant-filled biodome

for a series of videos on my channel

about how we interact with the air we breathe.

I have a bunch of safety equipment,

including oxygen and carbon dioxide sensors

and other gases and backups and blood monitors

and a paramedic onsite.

Do not try this at home.

It is...

Just don't try it at home. [laughing]

I wanna step back 60 years ago

to when carbon dioxide levels in our atmosphere

were around 300 parts per million.

Modern day, because of industrialization and burning fossil fuels,

those levels are now around 400 parts per million

in natural landscapes.

And in urban environments, it's more like 500 parts per million.

But the thing is, we spend most of our time indoors,

and that's often in poorly-ventilated spaces

where the carbon dioxide levels can reach 1,000 parts per million.

And what's important here is that researchers have gone out

and tested the higher-order decision-making abilities

of office employees at different levels of carbon dioxide,

and they found that at 1,000 parts per million,

there is a 15% decrease in cognitive function.

[takes breath]

That's a big deal because we spend a lot of our time

in those sorts of environments.

For example, researchers went to schools

in Texas, Idaho, and Washington,

and they found that in over 50% of those classrooms,

the carbon dioxide levels went above 1,000 parts per million.

In those same studies, they found that when levels reached 1,400,

there was a 50% decrease in cognitive function.

And by 2,000,

there are all sorts of side effects, [laughing]

which I am feeling a lot of, including nausea,

loss of attention, uh... [laughing]

I have to read, I have to read them.

Some people report headaches, sleepiness, poor concentration, loss of attention,

in- increased heart rate, and slight nausea.

But still, these levels aren't uncommon.

Carbon dioxide levels in bedrooms and cars frequently reach 4,000 parts per million,

and those are places that we spend a lot of our time in.

We used to use carbon dioxide as an indicator for when air was stale,

but it's actually probably the most important part

of what makes air stale.

It's 6,500 parts per million in here right now

and the air feels thick.

It is clouding my brain.

It is making me do way more takes in this video than I would've hoped.

When we reach 10,000 parts per million,

you're not supposed to work an eight-hour day

in an environment like that

because it's probably bad for your long-term health.

You wouldn't want to be riding a motorcycle

with that much carbon dioxide around you, but

[takes breath]

research shows that it's not uncommon

for motorcycle helmets to have carbon dioxide levels that are that high.

And I cannot imagine being impaired at this level

and riding a motorcycle,

let alone at 10,000 parts per million.

Still, we have to go up quite a bit. We have to go all the way up to 30,000

before levels become extremely dangerous and potentially deadly.

Now, I have some bad news and I have some good news.

The bad news is that carbon dioxide levels are going to go up.

They might even reach 695 parts per million by the end of the century.

And that means that, globally,

we could end up with something like a 10%

or a 16% decrease in our cognitive function as a species,

and that's a big deal. [takes breath]

The good news is that we have the ability right now

to change the environments that we live in,

both in terms of the overall climate

and in terms of the stale air spaces that we inhabit.

[takes breath]

So, you can go out and open a window in your office.

I don't have that luxury, but you can.

You can get some plants in your house.

You can make sure that your HVAC,

your air ventilation systems are up-to-date and functioning,

[takes breath]

and then you can use that cognitive surplus,

you can use that bonus to your thinking abilities

to try and find solutions for climate change

and how you can make a difference.

Tom, thank you so much for having me.

I'm gonna lie down and stop talking.

- Thank you, Kurtis! Go subscribe to his channel.

You can start with his series from inside his biodome

or, if that is a bit much right now,

I also recommend his one-take video on the entire history of the universe.

Next week is the final guest video, and it's all about neuroscience.