Second IMO GHG study 2009

The second IMO GHG study was commissioned in 2007 and delivered in 2009. This study updated the GHG emissions figures/inventory for shipping and estimated the potential for reduction of emission according to the implementation of different technologies and operational energy efficiency measures. In addition, cost effectiveness and policy evaluation options were considered. This second study initiated a proposed framework to support the regulatory decision-making process.

Presented during the Copenhagen UNFCCC’s COP discussions on climate change in December 2009, the Second IMO GHG Study 2009 forms the scientific background for the present IMO policy and regulatory frameworks that was developed soon thereafter. The intention of the document was to provide a solid research-based data and information to the shipping community in order to help them for regulatory decision making. Mr. Mitropoulos, the then Secretary General of the IMO recalled in a foreword to the document its objectives:

“I trust that this Second IMO GHG Study will become the paramount reference for the Organization’s Marine Environment Protection Committee in making well-informed and balanced decisions towards the development and adoption of a robust regime to regulate shipping emissions at the global level.

This study is documented under nine chapters as follows:

  1. Executive Summary
  1. Introduction to shipping and its legislative framework
  1. Emissions from shipping 1990–2007
  1. Reductions in emissions achieved by implementation of MARPOL Annex VI
  1. Technological and operational potential for reduction of emissions
  1. Policy options for reductions of GHG and other relevant substances
  1. Scenarios for future emissions from international shipping
  1. Climate impact
  1. Comparison of emissions of CO2 from ships with emissions from other modes of transport

A large number of Appendices are also included in the report. Below, some of the chapters more relevant to topic of this training course are further elaborated.” (IMO: Module 1. 2016, 41-43).

Third IMO GHG study 2014

Before making the inventory of the GHG emission by shipping, the chapter begins with few introductory comments on the scope and uncertainties. Accordingly, the scope of the emission included in the inventory is taken the same as those in the UNFCCC guidance.

“In line with the above-mentioned guidelines for creating an inventory of emissions, the following pollutants were considered for exhausts: NOx,

SO2, PM10, CO, CO2, N2O, CH4 and NMVOC.

The limitations on estimation of the emissions levels are then deliberated and the following considerations are made:

  • Exhaust gases uncertainties are the same as those of the previous study and are estimated to be around +/- 20%.
  • Emission of ODS are detailed by sources: Refrigerants, reefer ships & reefer containers; calculation limits are presented.
  • Limits and uncertainties in estimating the release of Methane (CH4) and Non-Methane Volatile Organic Compound (NMVOC) are presented.
  • Sulphur hexafluoride (

SF6) and Fluorocarbon (PFCs) on board ships are not emitted to any sufficient degree to be considered as significant issues.

Despite all these limitations, the emissions levels from international shipping were established. As table below indicates, amongst various types of the GHG emissions, the GHG emissions from shipping are overwhelmingly dominated by CO2. Thus, CO2 is established as the main GHG concern for shipping that should be the subject of future regulations. All other GHG emissions by international shipping are considered as negligible.” (IMO 2016, 42.)