Doesn't it make a difference if the tomato comes from the US, Australia or Spain?
A common question we receive is how assessing the climate impact of a recipe can work given that ingredients can originate in various countries. In other words, how can we tell whether ‘your’ tomato comes from the US, Spain, or the Netherlands? In a nutshell we deal with this as follows: (i) we consider the climate impact of each ingredient-country of origin pair relative to a target country (considering both difference in production conditions as well as differences in the transportation and cooling requirements). Often, it turns out, there is no significant difference to be found. (ii) If there is a significant difference, we consider if the production countries are significant suppliers of the ingredient in the target country (drawing upon massive trade databases). If a country of origin isn't a significant supplier of an ingredient to a target country we ignore it (on the assumption that the consumer could not reliably choose to select or avoid the ingredient from that country of origin). (iii) If after this step a significant difference remains between two or more country of origin-ingredient pairs, we use the best case scenario for our calculations and try to help our users to make the best case scenario come true by providing information on the shopping list as to what to look out for/avoid.
