MnrAq

90 Third IMO GHG Study 2014
Figure 66: Top-down and bottom-up inventories for international shipping fuels,
from the Third IMO GHG Study 2014 and the Second IMO GHG Study 2009
Differences between the bottom-up and top-down estimated values are consistent with the Second IMO
GHG Study 2009. This convergence is important because, in conjunction with the quality (Section 1.4) and
uncertainty (Section 1.5) analyses, it provides evidence that increasing confidence can be placed in both
analytic approaches.
There are some important explanatory reasons for the detailed activity method reported here to have
fundamental similarity with other activity-based methods, even if they are less detailed. Crossplot comparisons
in Figure 67 indicate that the fundamental input data to the bottom-up inventory in the Second IMO GHG
Study 2009 appear valid, compared to the best available data used in the Third IMO GHG Study 2014.