FEBRUARY 26, 2013 — Underscoring the fact that restrictions on exhaust emissions from ships are only likely to get stricter, an Expert Workshop got underway this week at IMO Headquarters in London to begin updating the inventory of greenhouse gases (GHG) from international shipping. The aim is to provide reliable and up-to-date information for IMO's Marine Environment Protection Committee (MEPC) to use when looking at further measures to reduce GHG.

The Second IMO GHG Study 2009 estimated that international shipping emitted 870 million tonnes, or about 2.7 percent of the global man-made emissions of CO2 in 2007. An updated GHG inventory is needed as the estimate contained in the study did not take account of the economic downturn experienced globally since 2008.

Exhaust gases are the primary source of GHG emissions from ships, with carbon dioxide the most significant GHG, both in terms of quantity and of global warming potential.

An updated inventory would provide a baseline against which to assess the effectiveness of technical and operational energy efficiency measures for international shipping that entered into force on January 1, 2013.

The MEPC, at its sixty-fourth session in October 2012 endorsed, in principle, the outline for an update of the GHG emissions estimate. The Expert Workshop will look further at the methodology and assumptions to be used in the update. The Expert Workshop is expected to provide a a report on its work to MEPC 65, meeting in May this year.

In addition to carbon dioxide (CO2), a global GHG inventory of emissions of GHGs and relevant substances emitted from ships, engaged in international transport could include: methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), subject to data availability.

Other relevant substances that may contribute to climate change include: nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC), carbon monoxide (CO), particulate matter (PM) and sulfur oxides (SOx).

IMO has already adopted technical and operational measures to reduce emissions of GHG from international shipping. The Energy Efficiency Design Index (EEDI) was made mandatory for new ships and the Ship Energy Efficiency Management Plan (SEEMP) for all ships, under amendments to MARPOL Annex VI adopted in 2011. These amendments entered into force on January 1, 2013.