Why should you read this chapter?

Food systems use large amounts of natural resources and have significant environmental impacts; so what can we do to make them more sustainable?

To answer this question, we need to understand which types of food, methods of production, ways of processing, packaging, transporting, and consuming foods have greater impacts than others. In other words, we need data to understand the current situation, and to have a way to evaluate how environmental impacts would change (for better or worse) if things were arranged differently.

Life cycle assessment (LCA) helps us to do this. It is a method used for quantifying the various environmental impacts and resources used, throughout the entire lifecycle of a product or service.  LCA has been foundational in helping us understand which parts of food systems have the greatest impacts, and how they could become more sustainable.  Knowing something about the LCA approach makes it possible to critically evaluate the claims made by many research studies and broader media reporting, and allows for a deeper understanding of the information presented in other Foodsource chapters.

This chapter provides an accessible primer on the life cycle assessment (LCA) methodology. It addresses the following:

  • What is life cycle assessment?
  • How can an LCA approach can be applied to measure the impact of a food product or related process?
  • What are the complexities and uncertainties involved in performing LCA for food products and in interpreting their results?
  • What are the benefits and limitations of the LCA approach, including its role in assessing sustainability?

Key points

  • All food follows a pathway through time and space – or a life cycle – from agricultural production through to eventual consumption or waste disposal.
  • At each stage in the life cycle, resources are used (e.g. land) and outputs are created, some desirable (e.g. food), others not so (e.g. greenhouse gases).
  • These inputs and outputs, in turn, impact upon things we care about such as biodiversity, human health, resource depletion, and climate change.
  • LCA is an internationally standardised method for quantifying inputs and outputs related to a given amount of product or service, and for assessing their impacts.
  • The value of the LCA method is in understanding the impacts of the whole-system. This avoids the risk of improving one stage in the supply chain or impact of concern, while simply shifting the problem to another stage in the supply chain or onto a different concern.
  • Using LCA, we can ask questions about which ways of producing, distributing, consuming and disposing of foods, have the lowest environmental impacts.
  • Because LCA is about analysing systems, the method requires careful design choices about what elements to include or exclude in an analysis, and how any impacts are attributed to products and services.
  • The many variables, data sources  and design choices in LCA, introduce inherent uncertainty in LCA results, which is especially high for agricultural products.
  • Because LCAs are designed to answer specific research questions and come with inherent uncertainty, interpretation and comparison of their results must be done with care.
  • While LCA is an extremely useful tool for analysing food system sustainability, its results must be put in a wider context to evaluate the overall sustainability of a product or process.


Suggested citation

Garnett, T., Röös , E., Nicholson, W., & Finch, J. (2016). Environmental impacts of food: an introduction to LCA (Foodsource: chapters). Food Climate Research Network, University of Oxford.

Written by

Tara Garnett, Food Climate Research Network, University of Oxford;

Elin Röös, Swedish University of Agricultural Sciences

Contributing authors

Jessica Finch, Food Climate Research Network, Warwick University;

Will Nicholson, IntoFood;

Edited by

Samuel Lee-Gammage, Food Climate Research Network, University of Oxford;

Marie Persson, Food Climate Research Network, University of Oxford;

Reviewed by

Professor Mike Hamm, Michigan State University;  

Dr Elin Röös, Swedish Agricultural University;  

Dr Peter Scarborough, University of Oxford;

Dr Tim Hess, Cranfield University;  

Professor Tim Key, University of Oxford;

Professor Tim Benton, University of Leeds;  

Professor David Little, University of Stirling;  

Professor Peter Smith, University of Aberdeen;

Mara Galeano Carraro.

Reviewing does not constitute an endorsement. Final editorial decisions, including any remaining inaccuracies and errors, are the sole responsibility of the Food Climate Research Network.

Funded by

The production of this chapter was enabled by funding from the following sources:

The Daniel and Nina Carasso Foundation;

The Oxford Martin Programme on the Future of Food;

The Wellcome Trust;

The Esmée Fairbairn Foundation;

Jam Today;

Waste Resources Action Programme (WRAP);

The Sustainable Consumption Institute at Manchester University.

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