Hi Richard,
Thank you so much for coming back with this detailed explanation, its incredibly useful.
The point regarding EN15804 A2 moving from IPCC AR4 to IPCC AR5 is particularly interesting, as although the GWP of CO2 hasn’t changed, methane has increased from 25 to 28 (CO2e) but Nitrous oxide decreased from 298 to 265 (CO2e). This is something we can watch out for in future updates, but as you say this hasn’t affected UK LCI V18, then it seems like this hasn’t been a cause of some the variance being observed.
