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. 

If you’re a coffee drinker like me, you might feel a little guilty about all those paper cups you end up tossing out when you visit a café. 

But now that the pandemic is winding down, coffee shops like Starbucks are starting to let customers use their own cups again. So is it time for all of us to make the switch over to reusable coffee cups?

We had our reporters Cameron Leo and Lilly Roth Shapiro look into this question. 

Welcome Cameron and Lilly!

Cameron Leo: Hi Megan!

Lilly Roth Shapiro: Hello!

Megan Hall: So, I have to admit, when I first heard this question about reusable versus single-use coffee cups, I thought it seemed pretty straight-forward.

Cameron Leo: Yeah, us too. A quick Google search will tell you that single-use coffee cups create a lot of waste. They’re lined with plastic, so they’re difficult to recycle and most facilities won’t accept them. 

Lilly Roth Shapiro: But it turns out that reusable cups have their own problems, and trying to make an exact comparison between the two is pretty tricky.

Cameron Leo: To figure this out, we talked to Dario Cottafava. He’s a researcher at the University of Turin where he’s studied the environmental tradeoffs between single-use cups and their reusable alternatives. 

He says, it wasn’t easy…

Dario Cottafava: It’s quite a complex question. When you are to assess the environmental impact you have to consider the entire life cycle of a product.

Cameron Leo: It’s easy to overlook, but reusable mugs require a lot of materials, energy, and water at every turn in their life cycle: in how they’re made, how they’re washed, and how they’re disposed of. In all of these steps, the bulky reusable cup has a, well, bulkier environmental impact than a single paper cup.

Lilly Roth Shapiro: So in order for a reusable coffee cup to be worth it, you have to use it a lot! Dario’s study says you have to use just one glass bottle somewhere between 20 and 50 times for it to pay off. 

Cameron Leo: And most studies that look at other kinds of reusable mugs, like ceramic, steel, and plastic ones, had similar results.

Megan Hall: So as long as I use my reusable cup, say, everyday for a month or two, it’s the better choice for the environment?

Lilly Roth Shapiro: Yes, and it can make a pretty big impact too. One study found that the widespread use of reusable cups in the UK would result in a 76% reduction in climate impact.

Megan Hall: That’s awesome.

Cameron Leo: It is, but there’s a catch: how you wash your reusable mug makes a huge difference. 

Megan Hall: Why would that matter?

Cameron Leo: Hand washing your dishes is actually really inefficient. 

Lilly Roth Shapiro: If you’re hand washing your reusable cup with hot water after every use, you end up wasting so much water and energy that you might actually be better off just sticking with paper coffee cups.

Megan Hall: Wow.

Cameron Leo: Right, so  it’s really important that you’re picking out a mug that’s safe and easy to throw in the dishwasher.

Lilly Roth Shapiro: And speaking of picking out mugs, Dario made another really important point for us about going reusable.

Cameron Leo: Yeah. I don’t know if you’re like me, Megan, but I have an HUGE cache of mugs that I’ve collected from random places over the years…

Megan Hall: Oh yeah, big time.

Cameron Leo: I called my mom back at home and asked her to count how many we had in our pantry. It was bad.

Mom: [sound of clanging mugs] …eight, nine, ten…

Lilly Roth Shapiro: The whole point of a reusable mug is that you can just use one, rather than going through a bazillion paper cups every year. So having a bazillion reusable mugs defeats the purpose of going reusable.

Cameron Leo: Sorry mom.

Megan Hall: So, it sounds like when you make the switch to reusable, it’s really important that you stick with a few cups and take good care of them!

Cameron Leo: You got it. If you use just one cup and wash it in the dishwasher, you’re on track to reduce the emissions and waste from your coffee or tea drinking.

 Megan Hall: Great! Thanks, Cameron and Lily! 

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

You can also follow us on facebook and twitter- at  “ask possibly” 

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

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