Humans are running a dangerous experiment on our planet.

We're putting more and more carbon dioxide and other gases into the atmosphere, which are trapping the sun's energy, and lo and behold, our planet is heating up in response.

To fix this, we could cut carbon dioxide emissions, but that’s been hard.

What if there were a shortcut?

What if we could reflect some of the sun’s energy away before it had a chance to get trapped?

Like… maybe with space mirrors?!

Yeah, seriously.

[OPEN] Hi, I’m Joe, welcome back to Hot Mess.

Space.

Mirrors.

Ridiculous as that sounds, some people are taking this option very seriously.

Maybe you’re picturing a huge swarm of mirrors circling the Earth, or a saturn-like ring of reflecty particles.

Small problem: light carries momentum, so bouncing it away exerts a force on a mirror - just like bouncing away a tennis ball exerts a force on a racket.

This light touch would gradually nudge sunshields out of their orbits.

Heavier mirrors would be more stable, but heavy is not what you want when you’re launching things into space.

Fortunately, there’s a point in space where the Earth’s gravitational pull cancels out just enough of the tug from the Sun that a shield could stay directly between the two, orbiting the sun at the same rate as Earth, like a perpetual sunshade.

Now, there's a good chance we'll double the amount of CO2 in the atmosphere in the next few decades.

To cancel out the warming that would cause, we’d need to block about 2% of incoming sunlight, which would require moving a sunshield about the size of India to its special balancing point in space… which is about 6 times the distance from the Earth to the moon.

So space-mirrors are impractical - to put it lightly.

You know what’s more practical?

Volcanoes.

When volcanoes erupt, they spew out particles called sulfate aerosols, which scatter the sun’s light before it reaches Earth’s surface, cooling the planet.

We could use blimps or special airplanes to pump sulfate aerosols into the stratosphere, simulating a constant volcanic eruption that could cool the globe for just a few billion dollars a year.

That's a lot of money, but doing nothing would be way more expensive.

In the United States alone, natural disasters caused over 300 billion dollars of damage in 2017, and that figure is only going to increase as the world heats up.

There are other methods that are more down-to-earth, like using boats to spray sea salt into the sky to make ocean clouds bigger and brighter.

Or we could make Earth’s surface itself more reflective, by painting rooftops white and farming shinier crops, which is apparently a real thing?

Reflecting sunlight away could make the world cooler, but it could also make the world a lot messier.

For one, it wouldn’t fix other problems caused by carbon dioxide, like acidification of the ocean because solar shades don’t get rid of CO2 Blocking the sun would have some complex side effects like altering rainfall patterns and disrupting monsoons - which billions of people rely on.

And who knows what other disastrous side effects we might cause.

What’s more, if we ever decided to stop temperatures would rapidly jump up to close to where they would be if we hadn't ever tried to block sunlight in the first place.

We’re already performing one global experiment by emitting carbon dioxide.

Do we really wanna commit to another, hoping it’ll cancel out the first??

If we want to keep earth from getting hot, and from getting messy, there isn’t a sexy shortcut.

The obvious solution is the best solution - we have to reflect on how to stop emitting carbon dioxide.