contribution tree

Question

Hello. I have a problem of vizualisation of contribution on one product : castor bean production. When I try to find the main contributors of impacts, for instance climate change, I can't see where are they mainly coming from. I use contribution tree, sankey diagram, impact analysis. A big part of the impact is still missing. Is it a bug from the process/software ? it happens on a big numbers of impacts, whith differents LCIA. 
Should I take a corrected value by adding the main contributors ? (around 1.8 kg eq CO2 instead of 3.8 kg eq CO2).  Thanks for your help !

Answer 1

I think the impact is not missing but direct impact caused be the specific step. E.g. in the first step, total impact is 3.81 kg, direct impact of the castor production as first step is 1.89 kg, the difference is the supply chain below.

Comments

no I think you got confused now. The contribution tree shows the impacts, but distinguished in direct and supply chain. We should of course have also N2O in a climate change method, but this is not "openLCA" but the specific LCIA method. If you use e.g. the ecoinvent LCIA method that we also provide you will get the same results as on the ecoinvent site.