How sustainable is your daily cup of coffee?

By Mark Maslin, UCL

For many people, like me, coffee is an essential. It allows me to wake up and function in the morning. It gives me a much-needed boost during the day.  Unlike most food-stuffs, however, coffee is a purely luxury commodity. It is sometime referred to as a ‘drug food’, because it provides no nutritional value, and basically just makes us feel good. Yet, our research, recently published in Geo: Geography and Environment, shows that, weight for weight, unsustainably produced coffee has a carbon dioxide emission similar to that of cheese and half that of one of the worst offenders, beef. Many of us make this worse by adding milk.

Despite being a climatology professor, until a chance meeting on a flight to Ethiopia I had not considered the impact of my daily coffee on the environment or our atmosphere. By pure chance the person next to me swapped seat to be next to their friend and I got to spend the next 8 hours chatting with an extraordinary coffee entrepreneur, Josh Clarke.  Josh travels the world sourcing sustainable coffee from individual farmers to ensure they get the very best price, and he gets the very best coffee.  He and his colleagues at Clifton Coffee advise farmers how to improve the sustainability and productivity of their crops. He also let me know that there was a need for research on the carbon footprint of coffee – so began this project.

Coffee is the world’s 70^th most traded agricultural commodity. Over 9.5 billion kg is produced annually with a total trade value of $30.9 billion.   Coffee demand is expected to triple by 2050 as rapidly developing countries acquire the coffee taste. Coffee is grown in tropical regions where the ecosystems are considered fragile due to other human pressures and climate change.  As awareness of these threats have grown so has the demand for sustainable coffee products, and with that it key sustainable certification schemes have emerged. Fairtrade, for example, supports small producers by guaranteeing a price premium, which is meant to be used to enhance social, economic and environmental development. The Rainforest Alliance UTZ certification aims to mainstream sustainability across the coffee market; while private company schemes such as Starbucks Coffee Company, led Sustainable Coffee Challenge and Nespresso AAA Sustainable Quality Program have focused on reducing the carbon footprint of coffee. In our study, Carmen Nab calculated the carbon footprint of both conventional and sustainable Arabica coffee from two of the largest producers of coffee, Brazil and Vietnam.

The life cycle of coffee can be divided into four general stages: production, transportation, roasting, and consumption. The first three stages are generally the same for all types of coffee product, whereas the final consumption stage processes differ depending on the product type produced and the amount and type of milk used. We found the average carbon footprint of Arabica coffee from both countries was15.33 kg of carbon dioxide equivalent per 1 kg of green coffee (kg CO_2e kg⁻¹) for conventional coffee production and 3.51 kg CO_2e kg⁻¹ for sustainable coffee production. This 77% reduction in carbon footprint for sustainable coffee production, in comparison to conventional production, was due to reduction of agrochemical inputs during production, water and energy efficiency during milling, and using cargo ship rather than freight flight to export the coffee beans.

An average cup of coffee contains approximately 18g of green coffee so each kg of green coffee makes approximately 56 espresso beverages. The carbon footprint of your espresso beverage is 0.28 and 0.06 kg CO_2e for conventional and sustainable coffee respectively (9.2 and 2.1 g CO_2e mL^-1). Adding milk significantly increases the carbon footprint. For example, for conventional production of coffee beans, the carbon footprints for one serving of caffe latte, flat white and cappuccino are 0.55, 0.34 and 0.41 kg CO_2e respectively. When the coffee is produced sustainably, these values were reduced to 0.33, 0.13 and 0.20 kg CO_2e. Whilst the carbon footprint of coffee production is four times higher than that of milk (per litre) many of us tend to use a lot of milk in our coffee. Using non-diary milk products can significantly reduce this additional carbon footprint.

The good news is that there are other ways to make sure the footprint of sustainable coffee is even lower.  We suggest further reductions could be made by replacing agrochemicals with organic waste fertilisers and ensuring minimal use of pesticides. More efficient water use during production and using renewable energy are also important. The coffee beans can be roasted in the country of production reducing the transportation weight and boosting the local economy. Packaging can be reduced at the point of sale and the remaining carbon footprint could be offset through certified schemes potentially producing carbon neutral coffee.

Coffee’s global significance extends beyond its large consumption numbers to the well-documented human right issues and environmental burdens such as effluent releases, fertiliser use, and habitat destruction. Applying our recommendations correctly through certification schemes could mitigate the human rights and environmental impacts of coffee cultivation. A word of caution, however, sustainable certifications up to now have been limited as many of their criteria are difficult to monitor. The criteria are universal and lack location-specific requirements for maintaining environmental integrity and biodiversity. So continually improvement of the certification schemes is required along with ensuring that coffee producers, seller and consumers only purchase certified coffee.   

Sustainable coffee cultivation can play a crucial role in maintaining and providing ecosystem services at a local and national level and can have a substantial role to play in mitigating the agricultural sector’s environmental impact. As proactive consumers we can demand sustainable low carbon footprint coffee production that supports a thriving local economy so our daily (essential) luxury does not cost the earth.

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About the author: Mark Maslin FRGS, FRSA is a Professor of Physical Geography at UCL. He is a leading scientist with particular interest in understanding the climate change and the major challenges facing humanity in the 21^st century.  He has published over 170 papers in journals such as Science, Nature, and The Lancet, 10 books and over 60 popular articles (e.g., for New Scientist, Independent, Guardian, Telegraph, New York Times and The Conversation – currently over 2.9 million reads).  He appears regularly on radio and television, including BBC One David Attenborough’s ‘Climate Change: the fact’. His books include the high successful ‘Climate Change: A Very Short Introduction’ (OUP, 2014 and 21), The Cradle of Humanity (OUP, 2017 and 19) and The Human Planet: How we created the Anthropocene co-authored with Simon Lewis (Penguin, 2018). His next book “How to save our planet: the facts’ will be published by Penguin Life in early 2021.

This article is an expanded version of one that appeared in The Conversation, and which can be viewed here.

The cover image for this post is by Nab and Maslin.

Suggested further reading

Nab, C, Maslin, M. (2020). Life cycle assessment synthesis of the carbon footprint of Arabica coffee: Case study of Brazil and Vietnam conventional and sustainable coffee production and export to the United Kingdom. Geo: Geography and Environment. https://doi.org/10.1002/geo2.96