A view of Earth from a satellite in orbit.

Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

A while ago, we asked if anyone had big, crazy ideas about how to slow down climate change. And a few of you wrote in with the same question – can we send an umbrella into space to block the sun and cool the planet? 

Is that something we could really do? I’m here with Possibly reporters Will Malloy and Iman Khanbhai to find out. 

Will Malloy: Hi Megan! 

Iman Khanbhai: Hi! 

Megan Hall: An umbrella in space? How would that even work? 

Will Malloy: I know, the idea sounds almost impossible and even kind of silly – can you imagine how much fabric that would take! 

Iman Khanbhai: How would you hold it up? 

Megan Hall: Is anyone actually considering putting up an umbrella? 

Will Malloy: We asked Possibly’s founder and Brown University’s Provost for Sustainability, Professor Stephen Porder 

Stephen Porder: So an umbrella obviously, is not practical

Iman Khanbhai: But scientists are talking about something that isn’t too far off – 

Will Malloy: Putting a whole bunch of dust particles very high up in the atmosphere. 

Stephen Porder: So it’s like, a trillion little teeny umbrellas. The idea is, could we fly a bunch of airplanes, let out some particles into the very high atmosphere and let those particles reflect a little bit of sunlight. 

Iman Khanbhai: You might hear ideas like this called “solar geoengineering” – the idea is that we could temporarily turn down the temperature on Earth by blocking some of the sunlight that comes into the atmosphere and warms the planet.

Megan Hall: How do we even know if something like this would work? 

Will Malloy: Putting a bunch of dust into the atmosphere is basically what happens when a volcano erupts. 

Stephen Porder: Nature has already done the experiment. We know that if you inject a huge amount of particles into the upper atmosphere it will cool the planet. 

Will Malloy: Some scientists think it might be a good short-term way to bring down the temperature while we work on more permanent solutions. 

Megan Hall: That sounds pretty extreme! 

Iman Khanbhai: It is extreme. There’s even an open letter of over 400 scientists from around the world who are opposed to even researching this. 

Megan Hall: Tell me more about that debate….

Will Malloy: For one, if you start putting particles in the atmosphere, you’d have to constantly refresh the supply. Just like the ash from a volcano erupting doesn’t last forever, the dust particles would only stay in the atmosphere for a short amount of time. 

Stephen Porder: So you’d have to have this like network of planes. Putting particles up into the upper atmosphere continuously through good economic times, bad economic times, wars, whatever else 

Megan Hall: And human beings are not great at being consistent… 

Iman Khanbhai: Right – and stopping would have big consequences, which makes a lot of scientists worried about starting in the first place. 

Megan Hall: What would happen if we did stop?

Will Malloy: Putting up particles- like putting up an umbrella – would block some of the sun’s rays. But if we keep burning fossil fuels, that’s like continuing to pile up blankets around the Earth. 

Stephen Porder: Then you pull the umbrella away. And now you have all this blanket on top of you and you get the full effects of the sun, and this huge blanket and so you go from like, cooled down to very rapidly, very, very hot. 

Iman Khanbhai: Also, we’re not totally sure who would implement this strategy. A single country? One really motivated billionaire? 

Will Malloy: And, it could have effects we can’t even predict – like if we cooled the planet too much too quickly, it might impact agriculture or create strange weather conditions. 

Megan Hall: You said could, but we know that climate change will definitely impact agriculture and the weather. 

Iman Khanbhai: That’s exactly the core of this debate – 

Stephen Porder: Does this strategy, buy us time…? Or does it present a false hope that we don’t need to transition off of fossil fuels and just continue to cook the planet until we accidentally or on purpose, stop putting these particles in the atmosphere and experience this giant whiplash?

Megan Hall: I would not have guessed that those questions about sending an umbrella into space would have such a serious answer! 

Will Malloy: I’ll admit, I thought this question was a little unbelievable, too, but it turns out, the idea of blocking out the sun brings up some pretty interesting dilemmas. 

Megan Hall: Well, Will and Iman, thanks for getting into it! 

That’s it for today. For more information, or to ask a question about the way your choices affect our planet, go to thepublicsradio.org/possibly. Or subscribe to us wherever you get your podcasts.

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Possibly is a co-production of The Public’s Radio, Brown University’s Institute for Environment and Society and Brown’s Climate Solutions Initiative.

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