1. Transportforum
Session 41, 2012-01-12
The Regulation of Global SOx Emissions from Ships
IMO proceedings 1988-2008
ERIK SVENSSON
Department of Shipping and Marine Technology
Chalmers University of Technology
ABSTRACT OF LICENTIATE THESIS (Published May 2011)
MARPOL Annex VI regulates air pollution from international shipping. Emissions of sulphur
oxides (SOx) are regulated through a global limit for the sulphur content of bunker fuels
(referred to as a global cap) as well as a stricter limit in particularly sensitive areas, referred to
as SOx Emission Control Areas (SECAs). This thesis has investigated documentation from the
sulphur deliberations at the International Maritime Organization (IMO) for the purpose of
explaining how the initial proposals for reducing sulphur emissions from ships ended with a
global cap of 4.5% sulphur content in 1997, which was then revised in 2008 to 0.5% in 2020
(or 2025, subject to review in 2018).
The thesis does not provide a definitive history, but it gives an insight into how policy-making
could happen at IMO. From this thesis, we can learn how IMO works as an international
organization responsible for air pollution from ships and how it is reported in its documents.
Moreover, it illustrates how industry interests can affect environmental policy. The results
show a process that started in the 1980s when the regulation of land-based sources of
acidification raised questions over the contribution of emissions from ships. The issue was
raised at IMO in 1988. An early target was set to halve SOx emissions from ships by 2000.
The focus then turned to a regional approach and a supplementary global cap. This was
explained by the lack of support for a stringent global solution due to high costs for the oil
industry. A global cap was introduced merely to prevent a possible increase in the sulphur
content. The global average sulphur content at the time was less than 3%, though a 4.5%
global cap was adopted in 1997. The only motivation for this cap was that it was a first step in
a global regulation that could be amended in the future.
It then took until 2005 before Annex VI entered into force, and it was decided to revise it the
same year. The work started in 2006. Several different policy options were discussed
intensively, including a global uniform standard. It was concluded that the health effects from
particulate matter (PM) emissions were one of the main reasons for revising the sulphur
requirements to stricter limits. Nevertheless, high costs for the oil industry made the IMO
focus on keeping the SECA approach. A final agreement was met in 2008. It was a
compromise with stringent SECA limits and a global cap that would become stringent after a
review of the ability of the oil industry to supply enough quantities of distillate fuels.
It was concluded that the global cap still has no effect and should not be interpreted as an
emission ceiling until the future reveals its results. Moreover, the focus of the northern
hemisphere on the air pollution regime is an important factor explaining the acceptance of
moderate global regulation and stringent regional regulation. This thesis opens up for further
research into how air pollution is dealt with at IMO. Three frames of reference were identified
that could be used to study similar processes.
Keywords: MARPOL, Annex VI, global cap, sulphur oxides, SOx, air pollution, ships,
emissions, IMO, policy-making