emissions in that year were much greater, 47.6 million
metric tons (4.8% of international shipping emissions).9
Current measures are not enough to maxi mize the two-
fths reduction in domestic shipping emissions by 2050,
as is the aim of the Deep Deca rbonization Pathways Proj-
ect (DDPP) report for the United States.10 However, due to
the high potential for emissions reductions in the shipping
sector, if policies are enacted to encourage the uptake of
reduction measures and technologies, it is very probable
that the shipping industry could very nearly achieve this
target. Whi le there is no such target or implementing laws
in the United States, in April 2018 the International Mari-
time Organization (IMO), the United Nations specialized
body for shipping, agreed to reduce greenhouse gases f rom
international shipping emissions by at least 50% by 2050,
compared to 2008 emission levels.11
Ships transport about 90% of world trade by volume12
and the shipping industry’s importance to world eco-
nomic growth was recogniz ed by the creation in 1948 of
the I MO.13 Shipping is regulated by a mixture of custom-
ary international law, international treaties, and domestic
law. For the purposes of this chapter, the most important
international laws are the United Nations Convention on
the Law of the Sea (UNCLOS)14 and the International
Convention for the Prevention of Pollution From Ships
(MAR POL, so named for MA Rine POLlution).15 While
the IMO has introduced eciency and data collection
measures (detailed below) to limit the growth of green-
house gas emissions from international shipping, there is
general consensus that these measures taken together will
not unlock the required reductions. Indeed, the estimate
of a 50%-to-250% increase in shipping emissions by 2050
takes into account exist ing IMO emissions reduction mea-
10. J H. W ., P D D
U S, U.S. 2050 R, V 1: T R 31 (Deep
Decarbonization Pathways Project & Energy and Environmental Economics,
Inc., 2015), available at http://usddpp.org/downloads/2014-technical-report.
pdf [hereinafter DDPP T R].
11. IMO, UN Body Adopts Climate Change Strategy for Shipping, http://www.
(last visited May 1, 2018).
12. Secretary-General Koji Sekimizu, Foreword to I M
O, supra note 1.
13. IMO, Brief History of IMO, http://www.imo.org/en/About/HistoryOfIMO/
Pages/Default.aspx (last visited Jan. 26, 2018).
15. International Convention for the Prevention of Pollution From Ships,
adopted November 2, 1973, as modied by the Protocol of 1978, adopted
I.L.M. 546 [hereinafter MARPOL 73/78].
sures (but not the emissions reduction target agreed in
Apri l 2018).
is chapter provides a background to shipping regu-
lation (Section II), discusses legal issues pertaining to
greenhouse gas regulation for shipping (Section III), and
explains recommended measures for the United States as
well as states and private part ies to reduce shipping emis-
sions (Section IV). roughout this chapter, U.S. domestic
shipping means ships that travel direct ly between one U.S.
port and another U.S. port (without calling at the ports
of any other country). U.S. international shipping means
all shipping departing U.S. ports for the port of any other
country. As reduction measures are discussed throughout
this chapter, the potential greenhouse gas reductions will
be quantied where possible.
II. Regulation of the Shipping Sector
Regulation of greenhouse gas emissions begins with an
understanding of the international context in which ship-
ping is regulated—regu lations adopted by the IMO under
MAR POL and the manner in which countries can regu late
shipping under UNCLOS (ag, coasta l, or port jurisdic-
tion). In the United States, the two principal laws aecting
shipping are the Jones Act and the Maritime Security Act.
e U.S. Environmental Protection Agency (EPA) decided
not to regulate greenhouse gas emissions from shipping,
and international measures provide for only a modest
reduction in emissions. Still, the DDPP projects that a
two-fths reduction in domestic shipping emissions could
be achieved by 2050, and the IMO believes even greater
reductions are possible. e se reductions could have sig-
nicant co-benets for both ocea ns and human health.
A. The IMO and MARPOL
e IMO and MAR POL provide an international legal
framework within which greenhouse gas emission limits
for shipping can be, and have been, adopted. e IMO was
founded to improve the safety and security of shipping and
reduce pollution from ships. (Originally called the Inter-
governmental Maritime Consultative Organization, or
IMCO, the name was changed in 1982 to IMO.16) e
IMO is a membership-based organization and the United
States is a member. Environmental policy is debated and
agreed to principally at the meetings of the Marine Envi-
ronment Protection Committee (MEPC), a committee of
16. IMO, supra note 13.