Coffee Pollution

(Ia Balbuena-Nedrow/Emerald)

College students are major caffeine consumers. A 2018 study found that college students drink an average of 159 milligrams of caffeine each day, which is equivalent to over one-and-a-half cups of coffee; coffee is the number one method of caffeine consumption, according to the study. It’s no wonder why there are 12 coffee shops on the University of Oregon campus alone, not including two Starbucks, Espresso Roma, Dutch Bros, Sweet Life Petite and the Duck Store’s coffee shop right off of campus.

Most students say they drink coffee either for the energy boost or for the taste. Previous Daily Emerald articles have looked at the health impacts of coffee, but what is the environmental impact of such a high demand? There are many different factors within the coffee industry to look at when determining the environmental impact of a cup of joe. Assistant professor of chemistry Christian Hendon, affectionately nicknamed “Dr. Coffee” by Around the O, helped break down how the coffee industry impacts the environment.

Growing the coffee plants

There are two types of coffee: arabica and robusta. Arabica coffee is primarily produced in “The Bean Belt,” which spans across all continents around the Equator. Brazil produces the largest percentage of coffee in the world.

The coffee plant grows at higher elevations in shady, yet warm weather. While the demand for coffee has increased significantly, a 2017 study written by the Director of Horticulture and Center for Global Initiatives Sarada Krishnan found that the coffee plant’s need for shade discourages extensive deforestation of other tree species. Because of this, coffee plant growing indirectly encourages maintaining biodiversity if done in the best way.

Coffee plants require a lot of rain, but luckily the environment that they are cultivated in does the work. Krishnan also found that a coffee plant takes about four to five years to start flowering (the beans are found inside the plant’s berry) and produces for 20 to 50 years depending on level of care.

And as for pest control, coffee plants have developed their own natural pesticide: caffeine. That’s right, the chemical compound that students use to stay up during their 8 a.m. class is evolutionarily meant for killing bugs. Some pesticides still might be used on certain farms, especially since arabica has significantly less caffeine than robusta, but the main chemical pollutant is fertilizers, not pesticides. If grown in the right conditions, the need for fertilizers can be minimalized.

“At least as long as the coffee is on that tree, that tree is mostly growing unperturbed — independent of if it was certified USDA or not — they almost all are [grown without fertilizers and pesticides] because most of [the farmers] cannot afford fertilizers and pesticides,” Hendon said.

So, compared to other agricultural industries, Hendon finds the coffee plant industry is not that harmful for the environment.

Preparing the coffee beans

So the cherries are picked and the seed must be extracted from the cherry. Hendon points to three ways the seeds are extracted. One way is to leave the berries out to dry in the sun and then, either manually or by a low-energy machine, remove the dried berry from the seed.

“It’s no more energy inefficient than my computer,” Hendon said.

The second method is another low-energy machine that doesn’t require the seed to dry, but rather just sticks a hole in the berry to get the seed out (like coring a cherry). The third method uses a high-pressure washer to get the berry off the seed. This method requires a lot of water, so would be the most environmentally straining method of the three.

New methods are coming out to reduce the amount of water required during this process of production.

Then the beans have to be roasted, which requires electricity and heating. The energy source used to roast the beans depends on the roasting company and how the beans are collected: intact, grounded, etc.


According to the Krishnan, the U.S. is the largest coffee importer in the world, resulting in almost a quarter of the world’s demand. A 2013 study that looked at the CO2 emissions compared to the amount of coffee shipped found that every kilogram of coffee beans shipped represented 4.82 kilograms of carbon dioxide emissions. However, this study tracked coffee beans from Costa Rica to Europe, which is a much longer journey than from South America to here. So, the environmental impact depends where the beans are headed.

Individual companies determine the amount of plastic used to transport their beans. Roasted beans are very susceptible to going bad quickly and require an air-tight container to transport over several days.

Making the coffee

Now that the coffee beans have finally arrived to resident Starbucks or local shop, it’s time to make the coffee. The environmental impact depends on how one chooses to brew. Pour-over would be an example of the least impactful way to make coffee; using a Keurig with plastic K-cups is arguably one of the environmentally worst ways to make coffee. No matter how the coffee is made, one statistic remains relatively consistent.

“Only about 22 percent of the coffee mass that you roasted is dissolved in the water when you brew it,” Hendon said. “Any more and the coffee starts to taste bad, any less and the coffee tastes thin and not that good.”

So, most of the coffee mass is waste, and there’s not much that can be done because the right flavor profile is the priority. Hendon hopes that he or his peers can find a way to improve roasting to access 25 percent or extract even one percent more coffee because even that little change can be large on the coffee industry scale. This is the focus of Hendon’s most recent mathematics paper, which will be submitted soon for the long reviewing process.

“It’s pretty neat; I’m pretty excited about it,” Hendon said. “If you can get one percent more out of your coffee, you can use maybe 25 percent less coffee, and you’re being less wasteful overall.”

For now, leftover coffee grounds can be used as anything from fertilizer for certain plants to a natural face scrub. (More ideas for uses here.)

Carrying the coffee

According to Green Match, the world uses up to 16 billion disposable coffee cups each year. Those cups represent 6.5 million trees cut down, 4 billion gallons of water and enough energy to power 54,000 homes for a year. The decision to use a disposable or reusable cup might actually be the most environmentally intense decision of the whole coffee supply chain.

Climate Change and Coffee

The coffee industry isn’t the worst industry for the environment (as long as consumers use reusable cups and mugs). Environmental impacts of coffee compliments like milk and sugars, which are whole other topics.

But what about the changing environment’s impact on the coffee industry? With extreme changes in climates that used to be ideal for coffee plants (particularly the sensitive Arabica), the industry will suffer greatly. Rainfall in these regions is expected to decrease significantly and the increased temperatures will raise the spread of disease amongst the plants. Overall, there’s expected to be a huge decrease in suitable environments for coffee plants. Some scientists are trying to find ways to produce more resilient Arabica coffee plants, but the jury’s still out. So, don’t be surprised when latte prices starts creeping up.

“At some point, coffee’s price is going to go really high, and it’s one of those things where it’ll become a super luxury item,” Hendon said. “That’s going to be a product in a change in climate.”