Third IMO Greenhouse Gas Study 2014

Executive Summary 15
Summary of Section 2: Inventories of emissions of GHGs and other relevant
substances from international shipping 2007–2012
All data are calculated using the bottom-up method and the results of this study are compared with the Second
IMO GHG Study 2009 results in Figure 9 (all shipping). Figure 10 (international, domestic and fishing) presents
the time series of GHGs and other relevant substance emissions over the period of this study (2007–2012).
Calculations performed using the top-down method are presented in Section 2.3.
The trends are generally well correlated with the time series trend of CO 2 emissions totals, which is in turn
well correlated to fuel consumption. A notable exception is the trend in CH 4 emissions, which is dominated
by the increase in LNG fuel consumption in the LNG tanker fleet (related to increases in fleet size and activity)
during the years 2007–2012.
Agreements with the Second IMO GHG Study 2009 estimates are generally good, although there are some
differences, predominantly related to the emissions factors used in the respective studies and how they have
been applied. The Second IMO GHG Study 2009 estimated CH 4 emissions from engine combustion to be
approximately 100,000 tonnes in the year 2007.