Greenhouse gas emissions from international shipping increasing

The greenhouse gas emissions of global shipping are increasing and are expected to continue to increase under current policy, with emissions hitting an all-time high in 2017, warns a new study. 

The International Maritime Organisation (IMO)’s fourth Green House Gas (GHG) study has found that, on average, the greenhouse gas emissions of global shipping are increasing and are expected to continue to increase under current policy, with emissions hitting an all-time high in 2017, warns a new study.

Split into two key areas – emissions inventory and projecting future emissions – the study highlights the need for significant action to cut emissions by at least 50% by 2050 compared to 2008 levels, as required by the IMO.

In 2018, 937 million tonnes (Mt) of carbon dioxide alone were emitted by the sector – only 0.3% lower than emissions levels a decade earlier.

Satellite observations of shipping activity enabled researchers to discover that an estimated 30% of total shipping emissions fall directly within national government responsibility, which is twice the magnitude previously estimated, with 316Mt of the total 1056Mt of shipping emissions within national emissions responsibilities.

According to international guidelines, only shipping emissions that occur when ships sail on a voyage between two countries are the responsibility of the IMO. 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.

Methane emissions were found to have increased by 150% over the period due to a lack of regulation allowing for greater methane leakage, caused by an increase in the uptake of poorer quality engines.

Co-author, Dr Elena Hauerhof (UMAS), leader of the inventory work, said in a statement: “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 9,000 ships”.

Photo credit: Flickr Creative Commons

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