A method of calculating the carbon or greenhouse gas footprint of a food
composition includes determining the CO2 or greenhouse gas emission of
each ingredient by associating a total energy value with the ingredient,
determining the proportion of the total energy value contributed by each
of at least one energy source, where each energy source has a
characteristic CO2 or greenhouse gas emissions value, and then
calculating a CO2 or greenhouse gas emission value for the ingredient
based on the GHG emission values of each contributing energy source.
Also, optimizing the CO2 or greenhouse gas emissions in the formulation
of pet food employs this method.