The animal article of the month for February is ‘Invited review: a position on The Global Livestock Environmental Assessment Model (GLEAM)

The livestock sector is one of the fastest growing subsectors of the agricultural economy and it makes a major contribution to global food supply and economic development. However, it also consumes significant amounts of natural resources and alters the environment. In order to improve our understanding of the environmental impact of livestock supply chains, FAO developed GLEAM, the Global Livestock Environmental Assessment Model.

GLEAM is a modelling framework that can quantify the impacts of livestock production at the (sub) national, regional and global scales. It includes the impacts arising from the main processes during the three stages of livestock supply chains: (1) pre-farm production of inputs such as feed, energy and fertiliser, (2) on-farm livestock rearing and crop cultivation, and (3) post-farm processing and transport. The model captures the specific impacts of each process, offering a comprehensive and disaggregated picture. Key features include:

  • Global coverage of six livestock species and their edible products: meat and milk from cattle, buffalo, sheep and goats; meat from pigs; and meat and eggs from chickens.
  • Spatially explicit modelling of livestock distributions, climatic data, feed yields and biophysical processes that allows, for example, rations to be derived that reflect the local availability of feed resources in developing countries.
  • A herd model that enables livestock statistics to be disaggregated and variation in livestock performance and management to be captured.

Ultimately, the purpose of GLEAM is to help stakeholders identify ways to improve efficiency and reduce the impact of livestock production. To that end, it has been used in a variety of projects, for example in the identification of cost-effective ways of reducing enteric methane in Uruguayan beef production. Details of these applications are outlined on the GLEAM website ( along with other resources, including detailed technical descriptions, results, reports and multimedia.


This article is freely available for one month: ‘Invited review: a position on The Global Livestock Environmental Assessment Model (GLEAM)‘.

Author: M. J. MacLeod, T. Vellinga, C. Opio, A. Falcucci

The animal Article of the Month is selected by the Editor-in-Chief and is freely available for one month. View the recent selections


  1. “Stakeholders” covers a wide variety of interested parties. How flexible is the model as a tool for different audiences?

    1. You’re quite correct, stakeholders is a broad term. The main GLEAM model is quite complex to use, but there is a simpler, more user-friendly version (“GLEAM-i” – the “i” stands for “interactive”), that is publically available on the GLEAM website. It’s not really intended to support farm-level decision-making (there are plenty of farm carbon tools out there, of varying quality…) rather it is aimed at stakeholders looking at the bigger picture, i.e. governments, project planners, producers, industry and civil society organizations. Best wishes. Michael

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