IMO urged to take action on black carbon emissions

Three countries – Norway, Sweden and the United States – are asking the International Maritime Organisation (IMO) to take action to reduce shipping emissions of black carbon (BC).

In a joint submission to the next meeting of the IMO’s Marine Environment Protection Committee (MEPC), to be held in London on 22–26 March, the three countries conclude that:

• The Arctic climate is warming much faster than the rest of the planet;
• Rapid melting of Arctic land- and sea-ice is accelerating that warming;
• Black carbon emissions, especially when deposited on land- and sea-ice, are a significant contributor to that warming and melting;
• Reductions of black carbon now, can provide short-term climate responses that are absolutely necessary to forestall a climate tipping point, and
• Reductions of black carbon will have positive effects on human health.

According to their paper, international shipping annually emits 71–160 thousands tonnes of BC, equivalent to about two per cent of total global emissions. An estimated 85 per cent of shipping emissions occur in the northern hemisphere, and the release of BC emissions in northern shipping routes affecting the Arctic is particularly damaging. Black carbon is believed to constitute 5–15 per cent of ships’ emissions of particulate matter.

One main option for cutting BC emissions is to reduce fuel consumption from the world’s shipping fleet, and reducing vessel speed is particularly effective. Reducing speed by 10 per cent results in approximately 23 per cent lower fuel consumption, and accompanying reductions in pollutant emissions. A 34-per-cent speed reduction – even assuming a 40-per-cent increase in the number of vessels – can reduce emissions by some 57 per cent.

Moreover, BC emissions can be further reduced by the use of specific pollution control measures, such as:

• In-engine measures;
• Installation of diesel particulate filters (DPF);
• Use of water-in-fuel emulsification; and,
• Replacement of conventional fuel valves with slide valves.

Action is becoming increasingly urgent as shipping traffic in the Arctic is expected to grow substantially as the ongoing melting process opens up sea lanes in the region.

Source: Reduction of emissions of black carbon from shipping in the Arctic. Submission by Norway, Sweden and the United States. IMO document MEPC 60/4/24, 15 January 2010.