Future proposals on measures to control black carbon emissions in the Arctic will likely include a ban on the use of heavy fuel oil (HFO). Other measures that we may see proposals for in the not too distant future could have a big impact on which ships will be able to continue operating in Arctic waters as they will likely be more restrictive than mainstream emission control measures.
Consideration of the impact on the Arctic of emissions of black carbon from international shipping was on the agenda at the fourth session of the Sub-Committee on Pollution Prevention and Response (PPR 4), which met at the headquarters of the International Maritime Organization (IMO) in mid-January.
PPR 4 had several documents and information papers submitted on the subject, mainly relating to the results of studies undertaken on the accuracy and practicality of various black carbon (BC) measurement methods as well as observations about factors that contribute to BC emissions.
The workplan for this item, as defined by the 62nd session of the IMO’s Marine Environment Protection Committee (MEPC 62) calls for developing a definition of black carbon (BC); identifying the most appropriate measurement method(s) for international shipping; and investigating appropriate control measures. The Bond et al. definition for BC was approved by MEPC 68 but much work remains on the rest.
PPR 4 agreed that it would need an extension on the target date for completion of the current workplan from 2017 to 2019, and that intersessional work will be required even to meet this new target date. It will seek to finalize identification of the most appropriate method(s) for measurement of black carbon at PPR 5 (2018).
Discussions on BC showed divergence on opinions as to whether it is premature to begin to investigate control measures before appropriate measurement methods have been fully agreed. Some think this is premature as they fear it will lead to legislation before the merit of control measures has been proven, however, the door has been left open for proposals to allow progress on this third element of the workplan.
Any potential future control measures are only expected to be adopted for ships operating in or near the Arctic, as that is where BC emissions can have the most dramatic impact on global warming because it accelerates the melt of ice and snow in the region.
Current observations & future predictions
Studies suggest there is good correlation between several measurements methods that are part of the current measurement protocol for voluntary data collection studies, but even one method that has not been showing good correlation and is deemed impractical by most that assessed it has as yet not been excluded.
Most measurements have been done in laboratories. Doing measurements during actual operations is challenging and it seems many external factors have an impact on the result.
Fuel type has an impact on BC emissions, but the study results are not yet fully conclusive and overall it appears that engine load is a bigger factor. Reduced sulphur content reduced the overall PM emissions, but not necessarily the BC emission according to one study, with variable engine loads creating variable results between fuels of 0.10%, 0.50% and 2.50% sulphur content.
Studies are missing on BC emissions from low speed engines, and studies on the impact of using 0.50% sulphur fuel are as yet limited.
Environmental NGOs continue to push for a ban on the use and carriage of HFO in the Arctic, to reflect the one in the Antarctic, as a means to address BC emissions.
Looking ahead, and reading the signals, we may see a push toward requiring ships in the Arctic to use only very clean distillate fuels combined with particulate filter technology, or LNG, and exclude the use of scrubbers combined with HFO as an acceptable control measure.
But that will be a decision to take in the next stage of the IMO’s work on controlling the impact on the Arctic of BC emissions. Before then, there must be reliable measurement methods in place as well as more research to understand exactly which factors cause the worst BC emissions, and how these can best be controlled.
Report by Unni Einemo