Greenhouse gas (GHG) emissions from agriculture and forestry account for nearly a third of anthropogenic emissions globally. The aim of this research was to explore how agri-food companies, including Unilever, manage and assess the GHG performance of the farmers in their supply chains. Certification schemes were identified as a key mechanism for GHG management at farm level and a structured framework was constructed to enable a transparent comparison of how current schemes address GHG management and performance. It revealed that most schemes are management oriented and few look to quantify the GHG emissions of farming systems or set GHG performance standards.\ud
GHG calculators are an increasingly important tool to model and estimate farm GHG emissions. An in-depth comparison of three calculators revealed differences in methodology and in their underlying assumptions and data which have important implications when used by companies to assess farm performance and crops. GHG calculators are complex tools and, in four case studies using the Cool Farm Tool, the quality of the results was found to be highly dependent on the mode of implementation. Key factors included the level of support and verification provided by the company and the capability of the user. The GHG results obtained from the use of the calculator was shown to be sensitive to farm management practices and climatic conditions. \ud
Findings of the research provided Unilever (and the wider agri-food sector) with insights on the effectiveness of key GHG management and assessment mechanisms being used across agri-food supply chains at the farm level. Moreover, it has provided Unilever with a robust basis in which to define their future strategy for managing/assessing GHG in their agri-food supply chains and has recommended some future areas of work that would help to advance the agenda further