MnrAq

Inventories of CO2 emissions from international shipping 2007–2012 57
a) Total shipping b) International shipping
Figure 41: Time series of bottom-up CO 2 e emissions estimates for a) total shipping and
b) international shipping
1.3.6 Shipping as a share of global emissions
Inventories of ship emissions can be compared with global anthropogenic totals to quantify the contribution
of shipping to GHG totals from all human activity. The consortium evaluated AR5, a comprehensive technical
document that has assembled global emissions estimates (IPCC 2013). AR5 provides global emissions totals
for the year 2010 for a number of GHG substances, including CO 2 , CH 4 and N 2 O. It also refers to two sources
that provide annual CO 2 emissions for the years 2007–2012 (Boden et al., 2013; Peters et al., 2013). Totals were
converted from elemental C to CO 2 for comparison with the current study.
Comparisons of major GHGs from shipping are presented in Tables 20–23, using global totals identified in the
recent AR5 (IPCC 2013). For the period 2007-2012, on average, shipping accounted for approximately 3.1% of
annual global CO 2 and approximately 2.8% of annual GHGs on a CO 2 e basis. International shipping accounts,
on average, for approximately 2.6% and 2.4% of CO 2 and GHGs on a CO 2 e basis, respectively. These CO 2
and CO 2 e comparisons are similar to, but slightly smaller than, the 3.3% and 2.7% of global CO 2 emissions
reported by Second IMO GHG Study 2009 for total shipping and international shipping respectively.
Table 20 – Shipping CO 2 emissions compared with global CO 2 (values in million tonnes CO 2 )
Year Global CO 2
1
Total shipping CO 2
Third IMO GHG Study 2014
Percentage
of global
International shipping CO 2
Percentage
of global
2007 31,409 1,100 3.5% 885 2.8%
2008 32,204 1,135 3.5% 921 2.9%
2009 32,047 978 3.1% 855 2.7%
2010 33,612 915 2.7% 771 2.3%
2011 34,723 1,022 2.9% 850 2.4%
2012 35,640 938 2.6% 796 2.2%
Average 33,273 1,015 3.1% 846 2.6%
1
Global comparator represents CO 2 from fossil fuel consumption and cement production, converted from Tg C y –1 to million tonnes CO 2 .
Sources: Boden et al., 2013, for years 2007–2010; Peters et al., 2013, for years 2011–2012, as referenced in IPCC (2013).