Grounds for debate: Is tea or coffee the greener sip?

Tea and coffee are luxury goods. They're not required for us to survive but many of us feel we couldn't live without our daily dose of steaming hot caffeine. Tea is the second-most consumed drink after water and coffee isn't far behind — we drink billions of these beverages daily. 

And human culture is steeped in both drinks. Coffee traces its origins back to 9th century Ethiopia, where legend has it that a goat herder named Kaldi discovered the energizing effects of coffee berries by chance. Tea has its roots in ancient China, where the mythical figure Shen Nong is said to have accidentally poisoned himself and was saved by an errant tea leaf falling into his mouth. 

It took a while, but both addictive beverages finally reached Europe by the 17th century and became the drink of choice in the coffee and tea houses where public intellectuals met to discuss the issues of the day. Such was the popularity of these "drug foods," as they are known, that their trade helped fuel the expansion of empires. 

These days, they are farmed intensively, processed, packaged and shipped around the world, leaving their mark on the environment in the process.

What factors impact the environmental footprint of tea and coffee?

The impact of these beverages can vary depending on a number of factors. But there is some research looking at the entire life cycles of both products — from cultivation and transport to consumption and waste. The findings highlight agriculture as having the largest environmental impact.

"Of course, every farm is different," said Amy Stockwell, a life cycle analyst, who has spent 18 years in coffee research. "They're grown in different countries. The weather's different. Farmers treat their crops differently."

But the mechanization of tea and coffee harvesting, irrigation, and the fertilizers, which emit nitrous oxide, a powerful greenhouse gas, all contribute to the climate impact. Coffee, for instance, was traditionally planted in the shade of other trees. Now it's largely grown in huge plantations exposed to the sun, which requires more intensive use of water, fertilizer and pesticides. 

Cutting forests down to make way for tea and coffee plantations is another factor here. 

"Much of the deforestation that occurs in countries of the Global South serves to produce cash crops like coffee and black and green tea for export to countries of the Global North like Germany," said Lena Partzsch, a professor of comparative politics focusing on environment, climate and global supply chains at Berlin's Free University. 

Tea is driving forest clearance in countries like Sri Lanka and India. But coffee's link to forest loss is particularly well documented, with around 130,000 hectares of trees vanishing each year to make way for plantations, according to the 2023 Coffee Barometer. One study by Wageningen University in the Netherlands estimates that 5% of deforestation can be attributed to coffee.

The products also have to be processed for consumption. The environmental impact here depends on the kind of energy used — fossil fuel or renewables. 

Then comes transport. While estimates for tea and coffee differ, one decisive factor is whether the product is transported by sea or air. A 2021 UCL study found switching from airplane to cargo ship saw transport emissions drop significantly.  

Packaging leaves its mark too. The impact depends on whether it's plastic, paper from sustainable sources or recyclable. But packaging has its upsides. It cuts down on food going to landfill where it rots and emits the greenhouse gas methane. Coffee waste is a major challenge, said Stockwell. 

"How often do we brew an entire pot of coffee and then only drink half of it? I've seen some data in the past that said, typically a third of a pot of coffee is wasted," said Stockwell. 

So, what's better tea or coffee? 

Well, it's complicated. It's hard to compare a kilogram of tea to a kilogram of coffee and make firm recommendations because as with any "agricultural product, there is a huge range in variety," said avid tea-drinker Stockwell.

But researchers looking at the carbon footprint of a cup of tea versus a cup of coffee — without any sugar or milk — say the former wins the day, simply because we use less product per cup. A teabag contains about 2 grams of leaves and a cup of coffee uses about 7 grams of beans. 

If we add milk to the equation, coffee comes out worse too. Cow's milk has a big carbon footprint, and we tend to add more of it to coffee — think lattes and flat whites. 

"When you have your coffee and tea actually the biggest decision you make is what milk you put into them," said coffee-drinker and UCL professor Mark Maslin. So, switching to plant-based milk or drinking coffee or tea black is one easy fix.

What else can we do to lower the environmental impact of tea and coffee?

"Only heating up the amount of water that you need is very important," said Stockwell. "I always fill up the kettle more than I ought to. And of course, then I'm using all the extra electricity to heat more water than I'm going to use."

Other little tweaks include storing the products in airtight containers to stop them  going stale and buying loose leaf tea instead of tea bags, which often contain plastic so cannot be composted.

Businesses, farmers and governments have a role to play too. 

The 2021 UCL study on coffee found that using less fertilizer, managing water and energy more efficiently and exporting beans by cargo ship rather than plane, can slash the crop's carbon emissions by around 77%. 

Businesses can also use more environmentally-friendly packaging and renewable energy where possible. And some companies have signed up to voluntary schemes to ensure their supply chains are sustainable. Last year, the European Union passed legislation to force businesses to show products like coffee and cocoa don't come from deforested land.

That's important because coffee consumption is predicted to double in the next 25 years. At the same time the world is warming and the area suitable for coffee cultivation will halve. Coffee is a sensitive crop. 

"It's a bit like us. You know we like it nice and warm. We like a little bit of decent humidity. We don't want it too hot, sweaty," said Mark Maslin, adding that we must ensure "as our demand for coffee and tea grows, we don't resort to deforesting new areas for that production."

Edited by: Tamsin Walker

Listen to the full Living Planet podcast segment on the environmental impact of tea and coffee here.