Product-byproduct analysis

When two commodities occur together, how should we split the environmental footprint between them?

Examples

• Soybeans processed/separated into soybean oil and soybean meal: What should we say about the land footprint of each?
• A mined mineral that contains multiple elements, some more scarce and some more abundant: What should we say about the carbon footprint of each element?

Approaches

• Compare the prices of each product involved. Consider their environmental footprints to follow the same ratio.

There are probably more approaches (each with their own pros and cons). Surely this has been discussed in some academic papers involving estimating environmental footprints. Have any standard methodologies been established globally?^{[RESEARCH needed]}