Final answer:
A serving of milk chocolate generally has a higher greenhouse gas footprint than a serving of dark chocolate, largely due to the dairy farming needed for its production, which contributes significantly to greenhouse gas emissions.
Step-by-step explanation:
When comparing the kilograms of greenhouse gases (GHG) required to produce a serving of chocolate, the type with the higher GHG emissions depends on several factors, including the ingredients and production process. Dairy farming, which is necessary for producing milk chocolate, is a significant contributor to GHG emissions, particularly methane (CH4) and nitrous oxide (N2O).
Since dark chocolate contains less or no milk compared to milk chocolate, we can infer that it typically requires fewer GHGs to produce. The higher dietary energy factor of livestock used for dairy and the substantial water footprint for dairy products contribute to the environmental impact of milk chocolate. Therefore, it takes more GHG to produce a serving of milk chocolate compared to dark chocolate.