Black Carbon and the Heavy Fuel Oil Ban in the Arctic

Black Carbon and the Heavy Fuel Oil Ban in the Arctic

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Amanda Wee Amanda Wee, Research Assistant, Ocean Law and Policy, Centre for International Law, National University of Singapore

Yulu Liu, Research Fellow, Ocean Law and Policy, Centre for International Law, National University of Singapore

CIL/NCLOS Dialogue Symposium

Introduction

Shipping through the Arctic has increased by 40% between 2013 and 2025 due to the melting of the Arctic ice. The Arctic’s unique characteristics such as ice, seasonal darkness, and the presence of marine wildlife and indigenous populations consequently magnify the risk of oil spills and the effects of emissions from fuel combustion such as that of black carbon. While there is now a Heavy Fuel Oil (HFO) ban imposed in Arctic shipping by the International Maritime Organisation (IMO) through MARPOL, this ban is ineffective as it comes with exemptions. This post thus examines the initiatives by the IMO and highlights the present deficiencies with the present regulatory framework. It concludes with some proposed solutions to address the highlighted issues moving forward.

Heavy Fuel Oil (HFO)

HFOs constitute the most widely used fuel throughout shipping globally due to its low cost. It has a tar-like consistency and is the residual mixture leftover from distillation and cracking of crude oil. However, combustion of HFO releases toxic gas and particulate emissions such as sulphur dioxide, carbon monoxide, and black carbon, which have negative impacts on human health and the environment.  On top of the toxic emissions, HFO is especially dense and highly viscous, making it a fuel that flows very slowly, emulsifying on ocean surfaces harming wildlife and polluting coastlines.

The IMO has implemented two fuel regulations that are relevant to the Arctic. Firstly, a sulphur cap came into effect on 1 January 2020 through MARPOL Annex VI, regulation 14, which limits the amount of sulphur in fuel oil used on board ships. Secondly, the IMO implemented a HFO ban which came into effect on 1 July 2024 through a new regulation 43A in MARPOL Annex I. However, regulation 43A contains an exemption and a waiver. Regulation 43A.2 provides for the fuel tank exemption for ships that have the requisite oil fuel tank protection under regulation 12A, and Regulation 43A.4 provides for the Arctic coastal State waiver, allowing HFO to be carried and used as fuel in waters subject to the sovereignty or jurisdiction of that Arctic coastal State until 2029. Further, the definition of HFO in MARPOL does not encapsulate all fuels that qualify as HFOs.

Black Carbon

The combustion of HFOs emits black carbon, which is particularly significant for the Arctic. The 68th session of the IMO’s Marine Environment Protection Committee (MEPC) defined black carbon as a distinct type of carbonaceous material, formed only in flames during combustion of carbon-based fuels (see here, here, and here). Black carbon is distinguishable from other forms of carbon and carbon compounds contained in atmospheric aerosol because it has a unique combination of physical properties. First, it strongly absorbs visible light with a mass absorption cross section of at least 5 m2g-1 at a wavelength of 550 nm, which accelerates ice and snow melt by reducing surface albedo. Second, it is refractory and retains its basic form at very high temperatures, with vaporisation temperature at near 4000 K. Third, black carbon is insoluble in water or organic solvents, nor in other components of atmospheric aerosol. These properties make black carbon very difficult to remove once it forms and deposits on ice surfaces. Black carbon lowers the reflectivity of ice, absorbing significantly more heat, accelerating the melting of ice. Reportedly, black carbon has accumulated in the Arctic due to burning HFO and increasing Arctic shipping.

IMO on Regulating Black Carbon

In recent years, IMO has introduced international regulations to reduce emissions of nitrogen oxides (Nox Technical Code) and the sulphur content of fuel (Annex VI to MARPOL), which are linked to ground level ozone and particulate matter (including black carbon). In addition, IMO has introduced carbon dioxide reduction measures in the form of a ship energy efficiency design index (EEDI) requiring continual improvements in ship efficiency.  

Since the 58th session in 2008, MEPC has considered submissions on reducing emissions of climate forcing agents from international shipping, including information on the impact of black carbon. MEPC 60 (2010) considered a proposal (MEPC 60/4/24) by Norway, Sweden and the US, on reduction of black carbon from shipping in the Arctic. MEPC agreed that ship’s emissions of black carbon and other particulate matter affecting the Arctic region needed to be addressed specifically. MEPC 61 further recognised black carbon as a separate issue from other GHG emissions and invited further proposals to 15th session of its sub-committee on Bulk Liquids and Gases (BLG).

MEPC 62 (2011) delegated BLG to consider the impact of black carbon from shipping in the Arctic, including

  • develop a definition for black carbon emissions from international shipping;
  • consider measurement methods for black carbon and identify the most appropriate method for measuring black carbon emissions from international shipping;
  • investigate appropriate control measures to reduce the impact of black carbon emissions from international shipping.

The definition was adopted during MEPC 68, as introduced at the beginning of this section. PPR 3 (2016) provided a draft measurement reporting protocol for voluntary data collection of black carbon, and the draft was approved for PPR 5 (2018) to collect black carbon data and provided the most appropriate black carbon measurement methods for data collection.

IMO continues to investigate appropriate control measures and abatement technologies to reduce black carbon emissions from shipping, covering topics including enhancement of efficiency, using cleaner fuels, and exhaust treatment, alongside its discussions on measurement and reporting of black carbon emissions (see here and here).

Critiques of the HFO ban

The HFO ban has been heavily criticised by environmental NGOs. Firstly, the exemption and waiver provisions allow ships to continue using HFOs until 2029, which leaves 74% of Arctic shipping unaffected by the ban. This limits the ban’s capacity to reduce black carbon emissions, exacerbating the rapid melting of ice in the Arctic. Secondly, the HFO ban only covers a small proportion of HFOs burned and carried as fuel in the Arctic due to the definition of HFO in MARPOL Annex I which does not sufficiently cover all HFOs that have the potential to severely impact the marine environment. Thirdly, the HFO ban provides no guidance to the maritime sector operating in the Arctic on the suitable fuels that should be adopted in the Arctic. Consequently, the shipping industry has started blending fuels to meet the specifications as laid out in the sulphur cap and HFO ban under MARPOL, but these blended fuels are not well-tested in Arctic waters and have potential to negatively impact the Arctic.

Blended fuels vary in density, viscosity, and pour points, which heavily influence the fuel’s behaviour if they are accidentally spilled into the Arctic Ocean. The mixing of paraffins with HFOs by the shipping industry to avoid classification as HFO raises the pour points of these fuels, resulting in fuels that quickly solidify when they touch the Arctic Ocean’s surface, making clean-up efforts difficult. It has also been found that these hybrid fuels contain a high proportion of aromatic compounds, which increases black carbon emissions as compared to HFOs. Due to the harsh weather conditions in the Arctic, the recovery of spilled oil could be hindered or rendered impossible, leaving the oil to persist in the marine environment. The winds and currents in the Arctic would easily cause oil clumps to quickly spread and drift into shoreline regions and ice, causing long-term detrimental effects to the environment, local communities and wildlife in the Arctic. Oil spill equipment at present is also not designed to clean up oil clumps but only liquid oil. Hence, the clean-up of oil spills could become severely impaired and delayed.

The way forward

With regards to the HFO ban, there needs to be a revised definition of HFO under MARPOL Annex I. The viscosity, measured according to temperature, and pour points under Regulation 43A need to be revised such that viscosity is measured at 5 degrees Celsius and the upper pour point is 0 degrees Celsius, to capture blended fuels that have the potential to cause widespread environmental damage. There should also be a mandatory shift to polar fuels, which emit much less black carbon and are appropriate for use in the Arctic considering the Arctic’s unique characteristics. The IMO has agreed to discuss “polar fuels” as a new fuel category, and it remains to be seen the progress (here and here) made to ensure fuels used in the Arctic cut black carbon emissions and are easier to manage in the event of a spill.

Black carbon is regulated as a form of air pollution and can be regulated under Annex VI of MARPOL. Current discussions on black carbon at MEPC and its Sub-Committee on Pollution Prevention and Response (PPR) are focused on measurement, reporting and data collection, as a preparatory stage for future possible regulation, but IMO’s efforts on preventing air pollution, decarbonisation, and regulating HFO are also relevant to the reduction of black carbon emissions, including proposals on Emission Control Areas (ECAs). While implementing abatement measures to reduce black carbon emissions to protect the Arctic environment and improve human health, it is important to recognise that the technologies used to eliminate black carbon, especially switching to certain types of fuels, can possibly result in increased greenhouse gas (GHG) emissions. Therefore, it is crucial that black carbon mitigation measures are coupled with long-term decarbonisation efforts, paying attention to the balance between reducing pollutants and avoiding contributing to GHG emissions

This article is part of a series: CIL/NCLOS Dialogue Symposium

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