Safeguarding the oceans

Shipping is the backbone of global trade, with over 80% of goods transported by sea to and from communities all over the world.

There is virtually no industry on earth that is not reliant on shipping for at least some of its equipment and materials. According to the International Chamber of Shipping’s 2020 ‘Catalysing the fourth propulsion revolution’ report, the value of cargoes shipped by sea is close to $7 trillion annually.

The global fleet consists of 98,140 commercial ships of 100 gross tons and above (UNCTAD Review of Maritime Transport 2020). These ships carry everything from grains, chemicals, and spare parts for machines, to furniture, medications, and wind turbine sections. The volume of trade carried by sea reached more than 11 billion tons in 2019.

As the custodian of the 1954 International Convention for the prevention of pollution of the sea by oil (OILPOL Convention), the International Maritime Organization (IMO) assumed responsibility for pollution issues soon after it began operations in 1959. Subsequently IMO has, over many years, adopted a wide range of measures to prevent and control pollution caused by ships and to mitigate the effects of any damage that may occur as a result of maritime operations and accidents.

These measures have been shown to be successful in reducing ship-sourced pollution and illustrate the commitment of the Organisation and the shipping industry towards protecting the environment.  Of the 51 treaty instruments for the regulation of international shipping IMO has adopted so far, 21 are directly environment-related.

Commitment to emission reduction

The growing global awareness of the negative impacts of climate change have made it vital that every industry plays its part in reducing greenhouse gas (GHG) emissions. Although the economies of scale and productive value make shipping the most efficient means of transporting cargo, IMO is committed to ensuring that the shipping sector reduces its global carbon footprint. The Fourth IMO GHG Study 2020 shows that shipping’s GHG emissions increased from 977 million tonnes in 2012 to 1,076 million tonnes in 2018 (9.6% increase), largely attributed to a continuous increase of global maritime trade. The share of shipping emissions in global anthropogenic GHG emissions increased slightly, to 2.89% in 2018, from 2.76% in 2012.

CO2 emissions from international shipping cannot be attributed to any specific national economy due to its global nature and complex operation – after all, a ship may be owned by an individual in Greece, flagged with a ship registry in Panama, crewed by Filipino and Chinese seafarers, and operate off the coast of Turkey. What is needed is a global approach that matches the international nature of the sector.

Safeguarding the Oceans

The first set of international mandatory measures to improve ships’ energy efficiency were adopted on 15 July 2011, as part of the International Convention for the Prevention of Pollution from Ships (MARPOL). The Energy Efficiency Design Index (EEDI) for new ships and Ship Energy Efficiency Management Plan (SEEMP) for all ships have helped propel the global fleet forward on the path to decarbonisation. Regulation drives innovation.

In April 2018, the Initial Strategy on the reduction of GHG emissions from shipping was adopted. This policy framework sets key ambitions including cutting annual greenhouse gas emissions from international shipping by at least half by 2050, compared with 2008, and working towards phasing out GHG emissions from shipping entirely, as soon as possible in this century. It also aims to reduce the carbon intensity (CO2 emissions per transport work) of international shipping, as an average across the sector, by at least 40% by 2030, pursuing efforts towards 70% by 2050, compared to 2008. The initial GHG Strategy will be revised by 2023. >

Safeguarding the Oceans

More recently, in June 2021, key short-term measures aimed at achieving the reduction in carbon intensity of all ships by at least 40% by 2030 were adopted in line with the IMO Initial Strategy. These measures combine technical and operational approaches to improve the energy efficiency of ships. All ships will have to calculate their Energy Efficiency Existing Ship Index (EEXI) and ships over 5,000 gross tonnes will establish their annual operational carbon intensity indicator (CII) and CII rating. In other words, ships will get a formal rating of their energy efficiency – A, B, C, D, E – where A is the best and C is the required index minimum.

Not only does this boost transparency about how green the fleet is, but it sends a strong signal to the market. Administrations, port authorities and other stakeholders, as appropriate, are encouraged to provide incentives to ships rated as A or B; ships rated D or E for three consecutive years are required to submit a corrective action plan to show how they intend to achieve a rating of C or higher.

"It is also of note that on 1 January 2020, a new, compulsory limit on the sulphur content in the fuel oil used on board ships came into force,"

marking a significant milestone to improve air quality, preserve the environment and protect human health. Known as “IMO 2020”, the rule limits the sulphur in the fuel oil used on board ships operating outside designated emission control areas to 0.50% m/m (mass by mass) – a significant reduction from the previous limit of 3.5%. Within specific designated Emission Control Areas the limits were already stricter (0.10%). This limit has resulted in a reduction to sulphur oxide (SOx) emissions from ships, providing benefits for the environment and human health, particularly for coastal populations.

A cleaner, greener path

There are a number of ways in which emissions can be curbed, particularly CO2. The most obvious solution would be to consume less fuel through vessel optimisation, equating to lower emissions. Many operators are already striving to achieve this. In addition to the environmental benefits, there are also cost savings to be made on fuel purchases. Some operators are using software and equipment to optimise their engine efficiency, while others reduce their fuel consumption speed optimisation.

Increased digitalisation facilitating “Just-In-Time” (JIT) arrival of ships at ports, allows vessels to match their speed to the time at which a berth will become available. In addition to saving fuel costs when en-route, this also avoids the need for a vessel to anchor off a port, when it continues to use fuel and produce emissions that could impact coastal populations.

Meeting IMO’s ambitions to cut GHG emissions will mean switching to cleaner, low and zero-carbon fuels. However, the switch away from the fuel that most ships currently use (known as bunker fuel) to alternatives is complex, with no single solution that is suitable across the global fleet as of yet. Ammonia, hydrogen, LNG, methanol, wind-power, battery power and biofuels are all alternatives that are being explored. Some ships may adopt hybrid options. Early adopters must not only consider the power densities and safety issues around using alternative fuels, but also the infrastructure needed to reliably refuel their vessels at ports around the world.

A third option being explored is that of Market-Based-Measures (MBMs), which would serve to incentivise a switch to low and zero-carbon fuels. MBMs place a price on GHG emissions and serve two main purposes:

1.  providing an economic incentive for the maritime industry to reduce its fuel consumption by investing in more fuel-efficient ships and technologies and to operate ships in a more energy efficient-manner (in-sector reductions)

2.  offsetting in other sectors of growing ship emissions (out-of-sector reductions)

In addition, MBMs can generate funds that could be used for different purposes such as adaptation and transfer of technology.

Joint global journey

Transitioning the entire maritime sector – which not only includes ships and vessel crews that must be trained but also ports and other land-based infrastructure – to decarbonised operations will undoubtedly be a long and expensive endeavour. IMO is determined that no Member State country be left behind due to a lack of funding or barriers to knowledge.

To support the implementation of the emission measures and encourage innovation, IMO has initiated a range of global projects. These include the GEF-UNP-IMO GloMEEP Project (now concluded), the European Union funded global network of maritime technology cooperation centres (GMN project), the IMO-Norway GreenVoyage2050 project and the IMO-Republic of Korea GHG SMART Project. These projects span training and assistance in putting together a national action plan through to funding pilot projects and data collection. Participant countries are encouraged to share their knowledge and collaborate for regional development.

Safeguarding the Oceans

Industry involvement is an integral part of this journey and many of these projects actively seek input from individuals at the sharp end of the maritime and logistics sectors. A good example of industry participation in decarbonisation efforts is the Global Industry Alliance to Support Low Carbon Shipping (Low Carbon GIA). This is a public-private partnership, operating under the framework of the IMO-Norway GreenVoyage2050 Project, that brings together maritime industry leaders to support an energy efficient and low carbon maritime transport system. Leading shipowners and operators, classification societies, engine and technology builders and suppliers, big data providers, oil companies and ports have joined hands to collectively identify and develop innovative solutions to address common barriers to the uptake and implementation of energy efficiency technologies, operational best practices, and alternative low and zero-carbon fuels.

Industry buy-in is necessary for a successful transition and this collaborative spirit is integral to ensuring that the proposed solutions are fit for purpose in real world conditions. Many shipping industry bodies feed into the regulatory framework through international Non-Governmental Organisations (NGOS) which have been granted consultative status with IMO. Other NGOS represent other interests, such as environmental groups – ensuring a wide range of views are considered when regulations are developed.

Threat of invasive species

Decarbonisation dominates the current global discourse, but IMO is also working to curb other threats to the marine environment. One of these threats is that of invasive aquatic species, which can pose serious ecological, economic and health problems in their new environments. These species can be transported either on the hull or in the ballast water of a ship from one country/region’s waters to that of another. They may survive the journey to establish a reproductive population in the host environment, becoming invasive, out-competing native species and multiplying into pest proportions. Invasive species that cling to hulls also create friction and resistance to the smooth flow of vessels, thus requiring the ships to use more fuel for their journeys and increasing emissions.

The problem of invasive species carried by ships has intensified over the last few decades due to the expanded trade and traffic volume. Quantitative data show that the rate of bio-invasions is continuing to increase at an alarming rate and new areas are being invaded all the time. Bacteria, microbes, small invertebrates, algae, eggs, cysts, and larvae of various species are causing enormous damage to biodiversity. Direct and indirect health effects are becoming increasingly serious and the damage to the environment is often irreversible. Moreover, significant economic impact occurs to various industries that depend on the coastal and marine environment, such as tourism, aquaculture, and fisheries, as well as costly damage to expensive infrastructure. Ballast water, which is used to stabilise a ship when loading and unloading cargo, has in the past carried multiple species from one location (where it was loaded) to another (where discharged) if it remains untreated. A prime example comes in the form of various species of toxic algae (red/brown/green tides) that may form harmful algae blooms in their environment. Some species can cause massive deaths of marine life through oxygen depletion, release of toxins and/or mucus. Beaches may be fouled, impacting on tourism and recreation. Some species may contaminate filter-feeding shellfish and cause fisheries to be closed. Consumption of contaminated shellfish by humans may cause severe illness and death.

Tackling the issue

Preventing the transfer of invasive species and coordinating a timely and effective response to invasions requires cooperation and collaboration among governments, economic sectors, non-governmental organisations, and international treaty organisations. The UN Convention on the Law of the Sea (UNCLOS) provides the global framework by requiring States to work together “to prevent, reduce and control human caused pollution of the marine environment, including the intentional or accidental introduction of harmful or alien species to a particular part of the marine environment.”

IMO Member States adopted the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004 (BWM Convention), demonstrating their clear commitment to minimising the transfer of invasive aquatic species by shipping, specifically through ballast water. The Convention requires all ships to implement a ballast water management plan. All ships have to carry a ballast water record book and are required to carry out ballast water management procedures to a given standard.

Safeguarding the Oceans

Parties to the Convention are given the option to take additional measures which are subject to criteria set out in the Convention and to IMO guidelines. Many vessels are now equipped with Ballast Water Treatment Systems (BWTS), which may use UV exposure, chemicals, inert gas, or other means to either kill or make organisms in the ballast water non-viable, such that they will not be harmful to the environment that they are discharged in.

Another convention aimed at protecting marine life is the International Convention on the Control of Harmful Anti-Fouling Systems on Ships, 2001 (AFS Convention). This Convention is focused on the prevention of adverse impacts from the use of anti-fouling systems and the biocides they may contain. As most vessel operators are aware of the commercial need to have smooth hulls for optimal operations, this Convention aims to ensure that the coatings, paints, surface treatments, surfaces or devices used on a ship to control or prevent attachment of unwanted organisms do not negatively impact the marine environments that they come in contact with.

One of the most effective anti-fouling paints, developed in the 1960s, contained the organotin tributylin (TBT), which has been proven to cause deformations in oysters and sex changes in whelks. Under the terms of the Convention, Parties to the Convention are required to prohibit and/or restrict the use of harmful anti-fouling systems on ships flying their flag, as well as ships not entitled to fly their flag but which operate under their authority and all ships that enter a port, shipyard, or offshore terminal of a Party. A recent amendment will prohibit the use of the biocide cybutrene in anti-fouling systems from 2023, following evidence that cybutrene is highly toxic for many marine organisms.

Meanwhile, IMO is working through its GloFouling project to support States to implement biofouling guidelines, which aim to ensure good biofouling management and prevent the spread of aquatic invasive species that may attach to the hull and other undersea structures of a ship.

Since the volumes of seaborne trade continue to increase, these conventions serve a vital purpose in protecting the marine environment and safeguarding the interests of the various stakeholders that rely on the oceans.

Oil spills and response

Perhaps the most visible of all threats to marine environments is oil spills from vessels. Regulations put in place by IMO have helped reduce the number of oil spills over the years.  Indeed, data from ITOPF shows that there were zero large oil spills from oil tankers in 2020, and just three medium spills. This figure was the same as 2019, and the lowest in any year since the 1970s. 

Of course, preparedness for any eventual maritime incident and accidental oil or chemical spill is essential. IMO’s International Convention on Oil Pollution Preparedness, Response and Co-operation 1990 (OPRC 90) provides a framework designed to facilitate international co-operation and mutual assistance in preparing for and responding to major oil pollution incidents. This is supplemented by the Protocol on Preparedness, Response and Co-operation to Pollution Incidents by Hazardous and Noxious Substances, 2000 (OPRC-HNS Protocol), which addresses pollution incidents involving hazardous and noxious substances, i.e. chemicals.

States which are party to OPRC 90 and OPRC-HNS Protocol are required to establish a national system for responding to oil and HNS pollution incidents, including a designated national authority, a national operational contact point and a national contingency plan. This needs to be backstopped by a minimum level of response equipment, communications plans, regular training, and exercises. OPRC 90 and OPRC-HNS Protocol 2000 provide a mechanism for Parties to request assistance from any other state Party, when faced with a major pollution incident.

This comprehensive set of regulations is designed to enhance safety of shipping, to prevent accidents occurring in the first place, and to mitigate the impacts of an accident should one occur. These regulations address everything from construction of ships to safety management to training of seafarers.

Safeguarding the Oceans

The system of mandatory casualty investigation and feedback into the regulatory system is intended to ensure any lessons are learned from a casualty, so action can be taken to better enforce existing regulation, or, if deemed necessary, to update or amend the regulatory framework.

When it comes to pollution preparedness, each year the Technical Cooperation Programme organises numerous workshops around the world to strengthen national capacities and enhance regional preparedness in case of oil spills on topics such as incident management, shoreline response, contingency planning, liability and compensation, transboundary cooperation, and waste management.

Additionally, IMO has an established network of experts that can be called upon and deployed – based on a request for assistance by a Member State – to provide advice and technical assistance in the event of an oil spill. This was the case in the oil spill involving the bulk carrier MV Wakashio, off the coast of Mauritius in July 2020. In this instance, IMO and the UN Office for the Coordination of Humanitarian Affairs (UN OCHA) jointly deployed an expert, who advised the Government of Mauritius on oil spill response and related matters – such as clean-up strategies, communication, guidance for volunteers, incident management, etc. The expert’s mandate also included assisting with possible follow-up actions, such as the review of the national oil spill contingency plan.

Numerous guides have been developed and published on topics related to oil pollution preparedness to support Member States in preparing for and responding to such incidents. The triennial conference series encompasses the International Oil Spill Conference (Americas) Interspill (Europe), Spillcon (Asia Pacific), alternating on a three-year cycle, where experts and Government officials come together to share the latest technical information and research relating to oil pollution preparedness and response.

There is therefore a wealth of expertise and experience available to assist in the event of an oil pollution incident. The Pollution Prevention and Response (PPR) Sub-Committee continues to spearhead IMO’s work in this arena.


IMO Member States are responsible for monitoring, enforcement, and compliance. Ship owners and operators and all who work on ships also have a responsibility to make sure their ships are compliant with the IMO regime, which aims to ensure safe, efficient shipping which does not negatively impact the environment. Shipping serves the whole world but must be sustainable. Protecting the marine and atmospheric environment is a shared goal that benefits everyone and every living thing on this planet. n


International Chamber of Shipping (ICS)  2020 Catalysing the fourth propulsion revolution


UNCTAD Review of Maritime Transport 2020