Comment: Starbucks’ reusuable cups aren’t so climate-friendly

By David Fickling / Bloomberg Opinion

If Starbucks wants to start reducing the environmental impact of its drinking vessels, its plans for pumpkin spice latte season could be a step in the wrong direction.

The company is planning to move away from using disposable cups by 2030, Associated Press reported last week. All packaging will be reusable, recyclable or compostable by that date, although single-use vessels will still be available until a better long-term solution is found, according to a spokesperson.

How, then, to consider the range of “hauntingly beautiful Halloween drinkware” it announced earlier this month? There’s a glow-in-the-dark green plastic venti beaker; mugs shaped like pumpkins and skulls; and a six-pack of reusable cups decorated with ghosts and more pumpkins. Before you rush to buy, it’s worth considering a paradox: You may be better off, in environmental terms, getting your cappuccino in standard disposable paperboard.

Most of us think that single-use packaging is one of the most important threats to the environment out there; a consequence of its highly visible presence in our lives. Less obvious are the ways that materials, water and energy can add up to a comparable ecological toll.

While the advantages of switching to reusable cups are genuine, they can also be surprisingly slight, and dependent upon aspects of usage that few of us think much about. A seasonal-themed beaker that’s cleaned in the sink every day for a month and then stuck at the back of the cupboard once Halloween passes may end up having a higher climate impact than the 30 paperboard cups you’d use instead.

Washing, for instance, comprises about 90 percent of the emissions impact from reusable drinking vessels. The most efficient way to do that is in a fully loaded dishwasher, which uses less water and heating energy than standing at a sink cleaning by hand. As a result, mugs that aren’t dishwasher-safe — such as vacuum-insulated vessels, or those with cork liners — can have a markedly higher carbon footprint than ceramic, polypropylene or glass ones.

It’s also worth switching from thinking about the number of items you’re throwing away, to the amount of material you’re using. Reusable cups are so robust because they weigh many times more than disposable ones. That translates into a larger volume of raw materials. Tougher packaging substances are also normally heated to high temperatures during manufacture, consuming abundant energy. Steel foundries, glass furnaces and ceramic kilns all operate at well over 1,000 degrees Celsius (1,832 degrees Fahrenheit), and even plastics need to be heated to around 300 C, compared to temperatures of less than 100 C for paperboard.

One classic 1994 study found that it took about 14 megajoules to make a typical ceramic cup, compared to 0.55 MJ for paper and 0.2 MJ for polystyrene foam, a super-light material that’s rarely used for takeaway drinks these days.

All reusable cups have a “break-even point,” the number of times you have to use them before they become more environmentally friendly than the disposable alternative. If you drink from a ceramic mug 20 times before breaking it or sticking it in the attic, you’re almost certainly better off using 20 paper cups instead. If you use it 2,000 times, it’s clearly the superior option.

A 2021 review of research on the subject by the U.N. Environment Program found that it might take several hundred uses before earthenware mugs start having a lower carbon footprint than disposable ones. Most people will probably get that many turns out of such a cup, but it’s a less dramatic difference than one might imagine. One of the studies reviewed (commissioned by — hmm — two Finnish paper and packaging companies) found that ceramics never reached such a break-even point. Steel vessels perform better, but reusable plastic cups, breaking even after 30 uses or so, were best of all.

Our biggest problem in all this is that it’s not just our packaging that’s disposable, but our culture as a whole. In Victorian times, buying a plain tea service could consume about two weeks’-worth of a middle-class salary. Goods are incomparably cheaper now; and as a result, they’re easier to take for granted. If you buy an iridescent Halloween-themed venti cup and use it for four weeks in October before switching to one with fir trees and reindeer in time for Christmas, you may not be shrinking your carbon footprint at all. And beware: That $13 Wednesday Addams dress or $3.11 faux leather cuff that matches the latte cup so well in your Instagram story? It’s a piece of disposable plastic, too.

David Fickling is a Bloomberg Opinion columnist covering energy and commodities. Previously, he worked for Bloomberg News, the Wall Street Journal and the Financial Times.