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Using Exiobase, for the Process “Construction” in the UK, I get a direct carbon impact of 0.0426 kgCO2e/Euro. This is within the process tab. When I have moved this into a Product system and used the same impact assessment method (CML, 2001), the direct carbon impact has increased to 0.053 kgCO2e/ Euro - an increase of nearly 25%! See attached photos. If you click the box at the top of the Product system Sankey, it sends you to the Process, which has the 0.0426 kg/Euro impact.

Can you explain why there is a difference between the two? If it helps, the cut off was set to 0.01.

Screenshot 2021-02-27 at 22.10.21.png

Screenshot 2021-02-27 at 22.10.09.png

Edit: With images

in Miscellaneous by (120 points)
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by (62.3k points)
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Hi, the difference is coming from the life cycle; in the process tab, you see only the impacts of the process itself, in the product system, for the modeled life cycle.

Best wishes,


edit: I think you did not attach images

edit2: thank you for the images - the process calls itself, since construction GB has input from construction GB

0.2 Euro per 1 Euro - the process impacts are thus only for 0.8 Euros and you need to devide the process-specific impacts by 0.8 to get the specific results of the life cycle calculation, which is for 1 Euro.

by (120 points)
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Hi Andreas,

Does that mean  the "direct" contribution is different from the "process" contribution, even though double-clicking on the red box in the first picture takes you straight to the underlying process?

If so, could you explain how the "direct" boundary differs from the "process"?

Edit: Thank you Andreas