IMO releases final report of the Fourth GHG Study
4 August 2020
The International Maritime Organization (IMO) today released the final report of the Fourth IMO Greenhouse Gas Study. Prepared by a global consortium led by CE Delft, the study found that total GHG emissions from maritime shipping rose about 10% from 2012 to 2018.
Some of the key findings and projections include:
- The GHG emissions—including CO2, CH4 and N2O, expressed in CO2e—of total shipping (international, domestic and fishing) have increased from 977 million tonnes in 2012 to 1,076 million tonnes in 2018 (9.6% increase). In 2012, 962 million tonnes were CO2 emissions, while in 2018 this amount grew 9.3% to 1,056 million tonnes of CO2 emissions.
- The share of shipping emissions in global anthropogenic GHG emissions has increased from 2.76% in 2012 to 2.89% in 2018.
- Carbon intensity (fleet’s CO2 emissions per transport work) has improved for international shipping as a whole, as well as for most ship types. For instance, in 2018, the overall average carbon intensity across international shipping was about 30% lower than in 2008, as measured by the IMO’s Energy Efficiency Operational Indicator (EEOI). However, more than half of the fuel efficiency improvements have been achieved before 2012. The pace of carbon intensity reduction has slowed since 2015, with average annual percentage changes of only 1-2%.
- GHG emissions are projected to increase from about 90% of 2008 emissions in 2018 to 90-130% of 2008 emissions by 2050 for a range of six plausible long-term economic and energy scenarios.
These projected increases in GHG emissions are in a stark contrast to the IMO GHG emission reduction targets. In 2018, the IMO adopted a climate change strategy that set a goal to reduce the total annual GHG emissions from international shipping by at least 50% by 2050 compared to 2008.
The Fourth IMO GHG Study also found a striking, 150% increase in methane emissions from 2012 to 2018. The increase in CH4 emissions was largely due to a surge in the number of ships fueled by liquefied natural gas (LNG), many of which produce high methane emissions. Methane is a powerful warming agent, with the global warming potential over a 20-year period (GWP20) of 86.
The ICCT, a member of the consortium that prepared the study, has called on the IMO to include all greenhouse gases, including methane, in the next phase of the IMO’s Energy Efficiency Design Index (EEDI) to limit emissions from new LNG-fueled ships. Currently, only CO2 emissions are limited under the EEDI.
Even without regulatory limits, there is considerable pressure to reduce methane emissions from marine natural gas engines to validate industry claims about the GHG reduction potential of LNG as a marine fuel. For example, WinGD recently announced measures for their next generation dual fuel technology (X-DF2.0) based on recirculating cooled exhaust gas, iCER (Intelligent Control by Exhaust Recycling), that could reduce methane slip by up to 50% [4828].
The Fourth IMO GHG Study also included, for the first time, the inventory of black carbon (BC) emissions from ships. The study found that BC emissions increased approximately 12% from 2012 to 2018. The IMO is scheduled to agree on black carbon regulations next year.
Source: IMO MEPC 75/7/15 | ICCT