In our busy and tiring daily lives, the quest for a coffee fix leads many of us to the welcoming doors of cafes. Yet, in the pursuit of this caffeinated bliss, an environmental shadow hides – the disposable cup.

Whether it’s a steaming latte from Starbucks, a refreshing brew from Costa, or a soothing chai from the neighbourhood spot, chances are it’s nestled in a disposable cup, made out of paper, plastic or polystyrene foam, that you can toss in the bin on your walk back to the office.

While it is easy to forget about these single-use cups, the environmental implications extend far beyond their brief moments in our hands.

Thankfully, a cultural shift is underway. Increasingly, individuals are opting for reusable insulated cups or mugs, mirroring the gradual embrace of eco-conscious practices by coffee shops.

Notably, Starbucks recently announced a comprehensive “bring your own cup” (BYOC) initiative, extending beyond in-store orders to include drive-through and app-based purchases. This move underscores a growing awareness among both businesses and consumers regarding the detrimental impact of disposable coffee cups on the environment.

So what is the environmental impact of a single disposable cup? Quite a lot, it seems.

“The entire lifecycle of disposable cups, from raw material extraction to production and transportation, requires significant energy, contributing to environmental degradation,” Preetam Basu and Thanos Papadopoulos, professors at the Kent School of Business and co-authors of a 2022 report on coffee cup waste, said in an emailed statement. “The slow decomposition of disposable cups, especially those with plastic linings, can lead to the release of microplastics into the environment,” and on the off chance that your disposable cup winds up in waste bound for incineration, that process “can release pollutants into the air”.

Polystyrene

The first disposable cups were actually made from paper. However, the advent of polystyrene foam in the 1960s saw a shift due to its superior heat retention properties. Today, the United States churns out approximately 3 million tons of polystyrene annually, with a staggering 80% ending up in landfills, comprising about 25 billion cups per year.

The slow decomposition of polystyrene, lasting roughly 500 years, coupled with its production emissions, equates to a substantial carbon footprint, akin to that of millions of cars annually.

“Styrofoam cups are lightweight and inexpensive but are non-biodegradable and can persist in the environment for hundreds of years,” said Basu and Papadopoulos. “Improper disposal may result in litter that harms wildlife and ecosystems. Polystyrene foam can break into small pieces, leading to litter and posing a threat to wildlife that may ingest it.”

Moreover, the breakdown of polystyrene releases harmful chemicals into the environment, exacerbating health and ecological concerns. Consequently, various jurisdictions, from Maine to Los Angeles, have implemented bans on polystyrene foam, prompting a shift towards more sustainable alternatives in food service establishments.

Plastic

Plastic cups, another prevalent culprit in the disposable cup saga, pose similar environmental challenges. Comprising polypropylene (PP) or polyethylene terephthalate (PET), traditional plastics persist for centuries, contributing to oceanic pollution and human health risks through the release of microplastics and associated toxins.

Because it takes so long to break down, most of the 8.3bn metric tons of plastic ever created still exists. Depending on which type of plastic it’s made from and how it’s disposed of, the emissions from a single-use plastic cup ranges from 10g to 30g of CO2.

Plastics “do not biodegrade and can remain in the environment for hundreds of years, breaking down into microplastics that harm ecosystems and wildlife”, said Basu and Papadopoulos.

Around 10m tons a year of plastic has ended up in the ocean. It also works its way into our bodies as microplastics shed from water bottles, plastic cups, and our food. Those plastics can leech carcinogenic and endocrine-disrupting chemicals into our bodies.

While efforts to curb single-use plastics gain traction globally, particularly in the EU and UK, widespread legislative action remains elusive in the United States, albeit with progressive initiatives in states like California.

Paper

The transition from polystyrene foam to paper cups in the coffee industry during the 1980s seemed a step towards sustainability. However, recent revelations expose the hidden environmental costs of paper cups, exacerbated by their intricate construction and substantial resource consumption.

Instead of serving regular black coffee, coffee chains started offering specialty coffee beverages – lattes, cappuccinos, etc. To preserve the foam on those drinks, they needed a domed lid, which only fit on paper cups.

Although paper cups appear better for the environment, a 2023 study found that they can be just as toxic as plastic once they’re thrown away. That’s because paper cups aren’t just paper – if they were, all the hot water would leak straight out.

“Paper cups are biodegradable and compostable under the right conditions, making them a relatively better choice. However, paper cups often have a plastic lining to prevent leakage, which can make recycling difficult,” said Basu and Papadopoulos.

That plastic lining can take decades to break down, all the while leaching microplastics. But even without the plastic, decomposing paper is hard on the environment.

“If not properly disposed of or recycled, paper cups can end up in landfills where they decompose anaerobically, generating methane, a potent greenhouse gas.”

The manufacturing process, reliant on vast quantities of timber, results in substantial carbon emissions, challenging the notion of paper cups as a green alternative.

According to one study, a single paper cup with a paper sleeve emits about 110g of CO2.

What can be done

Corporate endeavours to mitigate single-use cup reliance represent commendable steps towards sustainability, but they are not the only factor in tackling the disposable cup crisis.

Rachel A Meidl of Rice University’s Baker Institute urges a more holistic approach to address the complex interplay of consumption and waste systems.

“A ban represents a singular solution that can be a shortsighted strategy for a society grappling with such an extensive and interconnected global waste problem,” she said.

Emphasising the importance of lifecycle analysis, Meidl underscores the need for comprehensive solutions beyond mere emissions reduction metrics.

“The best policies are those that encourage value retention by extending the life of products,” she said.

In this landscape of evolving environmental consciousness, biodegradable cups emerge as a promising alternative. Yet, consumer vigilance is paramount, with Meidl cautioning against blind faith in biodegradable claims without rigorous scrutiny.

“Some brands and manufacturers market their products as ‘biodegradable’ or ‘compostable’ when, in fact, there is no scientific basis for those claims.”

Ultimately, the enduring solution lies in the widespread adoption of reusable cups. That said, even reusable cups have climate impacts – they too have to be made, and additionally must be washed with hot water between uses.

Having said that, if used over 20-100 times (depending on the cup type), reusable cups are the better option and offer a tangible pathway to reducing waste and carbon emissions associated with disposable alternatives.

So every sip from a reusable cup represents a stride towards a greener future.