Fourth GHG study confirms rising trend in GHG emissions

The study reveals that total GHG emissions rose by 9.6% between 2012 and 2018, while international shipping GHG emissions increased by 5.6% over the same period.

While carbon intensity of shipping has improved, the increase in cargo volumes and passenger numbers has outweighed any improvement in efficiency. Carbon intensity (as measured by the AER metric) declined by 21% over the 2012-18 period.

Meanwhile, emissions forecastscontinue to show a wide variation in line with the underlying scenarios, given uncertainties about future GDP and tonnage growth rates, as well as the price level of zero-carbon fuels. Emissions could vary between 1,000 to 1,500 Mt CO2 in 2050, equivalent to an increase of 0 to 50% over 2018 levels. This was broadly in line with the revised scenarios assessed by CE Delft in a BIMCO sponsored study in 2017.

The introduction of a new voyage-based emissions allocation, based on AIS data, and tested against EU MRV data, has permitted revisions in the proportion of emissions allocated to national as opposed to international voyages. As a result, this has increased from 15% in the 3rd GHG Study’s vessel-based methodology to 30%. The implications of this change for the regulation of short-sea shipping by flag states with aggressive national CO2 reduction targets remains to be seen.

The report also includes detailed analysis of the proportion of emissions attributable to main engines, auxiliary engines and boilers, as well as a breakdown of emissions according to the phase of operation. The Motorship expects this will drive attention towards reducing energy consumption requirements during the loading and unloading of chemical tankers and oil tankers, both of which consume more than 20% of energy requirements while berthed, for example.

Finally, significant space is dedicated to a discussion about the contribution of CH4 (methane), nitrous oxide (N2O) and black carbon (BC) to GHG emissions. As noted, retrospective analyses based on methane emissions from older LNG-fuelled engines are unlikely to take into account the significant improvements in methane slip achieved in the latest generation of dual-fuel engines.

Table: Total shipping and voyage-based international shipping CO2 emissions 2012-18 (Mtonnes)