IMO GHG studies
To support evidence-based decision making on addressing GHG emissions from international shipping, IMO has since 2000 commissioned studies to estimate greenhouse gas emissions from the sector and project possible developments. These studies prepared by reputable research organizations across the world, under the oversight of a panel of Member Governments and the IMO Secretariat, are a global reference in estimating GHG emissions from international shipping.
Under a new voyage-based allocation of international shipping used in the Fourth IMO Greenhouse Gas Study (2020), CO2 emissions are estimated to have increased from 701 million tonnes in 2012 to 740 million tonnes in 2018 accounting for approximately 2% of global CO2 emissions.
The Third IMO GHG Study (2014), estimated international shipping emissions in 2012 to be 796 million tonnes, or about 2.2% of the global total anthropogenic CO2 emissions. The Study also updated the CO2 estimates for 2007 to 885 million tonnes, or 2.8%.
The Second IMO GHG Study (2009), estimated international shipping emissions in 2007 to be 880 million tonnes, or about 2.7% of the global total anthropogenic CO2 emissions.
In 2000, the First IMO GHG Study on GHG emissions from ships was published, which estimated that ships engaged in international trade in 1996 contributed about 1.8 per cent of the world total anthropogenic CO2 emissions.