Carbon References: Scope 3: Food

Scope 3: Food      
  Name Unit Source URL Calculations Notes
Food purchases Greenhouse gas emissions factor kg eCO2 / kg food Heller and Keoleian 2014, Greenhouse gas emission estimates of US dietary choices and food loss, Journal of Industiral Ecology DOI: 10.1111/jiec.12174 https://onlinelibrary.wiley.com/doi/abs/10.1111/jiec.12174 kg eCO2 / kg food Greenhouse gas emissions factors were collected from Heller & Keoleian 2014 for the food categories in SIMAP. The factors in Heller & Keoleian 2014 are averages by food category based on a literature survey conducted for the paper. Transport emissions for average food miles are included in these emissions factors. 
Greenhouse gas emissions factor for local food kg eCO2 / kg food Heller and Keoleian 2014, Greenhouse gas emission estimates of US dietary choices and food loss, Journal of Industiral Ecology DOI: 10.1111/jiec.12174; Weber and Matthews 2008, Food-miles and the relative climate impacts of food choices in the United States, Environmental Science & Technology 15: 3508-13. https://onlinelibrary.wiley.com/doi/abs/10.1111/jiec.12174; https://www.ncbi.nlm.nih.gov/pubmed/18546681 (kg eCO2 / kg food) * (1 - 3%) 250 miles was selected because it is a widely used average for local food miles. The greenhouse gas emissions factors from Heller & Keoleian 2014 were modified to reduce the tranport emissions. It was assumed that final transport accounts for 4% of greenhouse gas emissions from food (Weber & Matthews 2008), so the Heller & Keoleian 2014 emissions factors were reduced by 3% overall to account for a roughly 75% reduction in transport miles.