Why are plant production processes showing negative values in the LCI "ClimateChange" even though it is not reasonable.

Question

I am working with the ecoinvent data base. When I use Inputs such different types of animal feeds, grass silage etc. I receive negative figures because of considered CO2 uptake by plants. Can I easily ingnore this elementary flow? Usually plant production result in a balanced soil carbon status, so the CO2 footprint shouldn´t be negativ eventhough some carbon is stored in the product. For animal production processes it is on the other hand often not possible to calculate this respiration losses accuratly. I even do not know this situation, while I am working with the ecoinvent data in SimaPro.

Answer 1

Hi Thorsten, when plants grow they assimilate CO2 in their biomass ... that is why e.g. rain forests serve as huge CO2 sinks (obviously). Thus it makes sense, that in ecoinvent plants (during growth) have a negative CO2 impact. The respiratory emissions e.g. during digestion by animals only occur later in the supply chain and are not considered at the point of plant production. Thus, the (mathematically) negative environmental impact will only be canceled out if you consider the entire supply chain including the release of the plant(biomass) based CO2 back into the atmosphere. But again, only looking at the growth stage of plants I think it does make sense that the impact is negative.

I hope this helps.

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