In 2012, international shipping was estimated to have contributed about 2.2% to the global emissions of carbon dioxide (CO2). Although international shipping is the most energy efficient mode of mass transport and only a modest contributor to overall CO2 emissions, a global approach to further improve its energy efficiency and effective emission control is needed as sea transport will continue growing apace with world trade.
As already acknowledged by the Kyoto Protocol, CO2 emissions from international shipping cannot be attributed to any particular national economy due to its global nature and complex operation. Therefore, IMO has been energetically pursuing the limitation and reduction of greenhouse gas (GHG) emissions from international shipping, in recognition of the magnitude of the climate change challenge and the intense focus on this topic.
Source: International Maritime Organization