GHG emissions increase by 9 per cent since 2012, finds Fourth IMO GHG Study

GHG emissions increase by 9 per cent since 2012, finds Fourth IMO GHG Study
Tables 1 and 2 showing shipping emissions and carbon intensity 2012-2018. Image courtesy of the IMO

The Fourth IMO GHG Study has been published in full. The most recent estimates indicate that greenhouse gas (GHG) emissions of total shipping have increased from 977 million tonnes in 2012 to 1,076 million tonnes in 2018 (9.6 per cent increase) mostly due to a continuous increase of global maritime trade. The share of shipping emissions in global anthropogenic GHG emissions has increased from 2.76 per cent in 2012 to 2.89 per cent in 2018. 

Based on various long-term economic and energy scenarios (not taking into account long-term effects of the COVID-19 pandemic), and without any additional measures, the Study describes that shipping emissions are projected to increase from about 90 per cent of 2008 emissions in 2018 to 90-130 per cent of 2008 emissions by 2050.

Under a new voyage-based allocation of international shipping, CO2 emissions have also increased over this same period from 701 million tonnes in 2012 to 740 million tonnes in 2018 (5.6 per cent increase), but to a lower growth rate than total shipping emissions, and represent an approximately constant share of global CO2 emissions over this period (approximately 2 per cent). Using the vessel-based allocation of international shipping taken from the Third IMO GHG Study, CO2 emissions have increased over the period from 848 million tonnes in 2012 to 919 million tonnes in 2018 (8.4 per cent increase).

Carbon intensity has improved between 2012 and 2018 for international shipping as a whole, as well as for most ship types. Annual carbon intensity performance of individual ships fluctuated over years. The overall carbon intensity, as an average across international shipping, was 21 and 29 per cent better than in 2008, measured in AER and EEOI respectively in the voyage-based allocation; while it was 22 respectively 32 per cent better in the vessel-based allocation (Table 2). Improvements in carbon intensity of international shipping have not followed a linear pathway and more than half have been achieved before 2012. The pace of carbon intensity reduction has slowed since 2015, with average annual percentage changes ranging from 1 to 2 per cent.

Although it is too early to assess the impact of COVID-19 on emission projections quantitatively, the report states that it is clear that emissions in 2020 and 2021 will be significantly lower. Depending on the recovery trajectory, emissions over the next decades maybe a few per cent lower than projected, at most.

In the forward by the Secretary-General of the IMO, Mr. Kitack Lim, he states: “Whilst further improvement of the carbon intensity of shipping can be achieved, it will be difficult to achieve IMO’s 2050 GHG reduction ambition only through energy-saving technologies and speed reduction of ships. Therefore, under all projected scenarios, in 2050, a large share of the total amount of CO2 reduction will have to come from the use of low-carbon alternative fuels.”

Download the full report here.