GHG emissions of global shipping are increasing, and expected to continue to increase, under current policy, according to the 4th IMO GHG Study. Advances in this new study’s methods have estimated that 30% of total shipping emissions fall directly within national government responsibility, twice the magnitude previously estimated. The study’s findings and trends continue to set a significant challenge for governments domestically, and collectively at the International Maritime Organisation, if the sector is to contribute proportionally to achieving the Paris Agreement temperature goals. The study shows strong, clear policy action must be taken for the sector to urgently transition away from the use of fossil fuels.

The multi-disciplinary team at UMAS, which led the Third IMO GHG Study in 2014, also led the work on emissions inventories in the Fourth IMO GHG Study. The effort was a collaboration between 9 organisations from across 6 countries, made additionally challenging by Covid-19: disrupting normal collaborative working, and meaning the work had to be managed around Covid-19 induced caring responsibilities.

The emissions inventory produced made a number of advances, including the ability to estimate the GHG emissions for each ship in the global fleet, on every voyage it sailed. 316Mt of the total 1056Mt of shipping CO2 emissions (2.9% of total anthropogenic emissions) were within national emissions responsibilities. At 30% of total emissions, this is twice the magnitude estimated in previous studies.

According to international (IPCC) guidelines, only shipping emissions that occur when ships sail on a voyage between two countries are the responsibility of the UN agency the International Maritime Organisation. When any ship sails between two ports in the same country, the emissions are the responsibility of that country – and should be accounted for and have reductions managed within that country’s emissions inventory and commitments, including in its reports to the UNFCCC regarding commitments made in the Paris Agreement (Nationally Determined Contribution). Until now only a few countries had investigated their shipping emissions at this level of detail, and the IMO had had to make simplified estimates that have been shown to underestimate the level of emissions that count as ‘domestic’ shipping and fall within the responsibilities of individual governments to manage.

The study produced many further insights into the recent trends in shipping emissions and the drivers of these trends. Some of the main points relevant to the market and policy makers are described here, and the full report is available here.

Elena Hauerhof, UMAS, leader of the inventory work: “This study represents a significant step forward in estimating emissions inventories, and for the first time uses a fully IPCC -aligned approach to estimate international shipping emissions. The study has also significantly advanced the accuracy of AIS based estimations for any ship, and evidences this by undertaking a detailed validation against fuel consumption and other key parameters reported in EU MRV for over 9000 ships”

Tristan Smith, UMAS, contributor and director UMAS: “You have to start by getting GHG accountancy right, and this has proved a perennial problem for the shipping sector. Most countries, including the UK, continue to count shipping emissions inaccurately e.g. on the basis of fuel sold to shipping as opposed to actual voyages and activity. Very few countries use IPCC aligned methods, or include shipping in their NDC – it’s a poorly-assessed, under-examined and often-ignored sector for many governments. Poor accountancy creates persistent underestimation of the magnitude of responsibility and role that should be taken nationally to decarbonise shipping. Hopefully this study will encourage countries to look again, and bring shipping firmly into their national GHG policy and action.”
Source: UMAS (University Maritime Advisory Services)