Lumbering across the world's oceans at a leisurely pace, they seem relatively blameless compared with planes or lorries. But the role of cargo ships in exacerbating climate change is about to come under scrutiny. The solution? Slow down.
Speed limits in the world's shipping lanes will be proposed today by Ruth Kelly, the transport secretary, when she announces plans to regulate greenhouse gas emissions.
Studies suggest that, although ships use less fuel than planes or lorries to carry a tonne of cargo, the industry is so big that it accounts for up to 4.5 per cent of global emissions of carbon dioxide, the most prominent greenhouse gas.
Kelly will tell a meeting of the International Maritime Organisation that more must be done to tackle emissions from shipping, 'the most urgent and serious' challenge for the industry. She will call for operational improvements such as slowing down ships to maximise fuel efficiency and for more research into hydrogen fuel cells for power.
Martyn Williams, of Friends of the Earth, said: 'There's been a big focus on aviation because the plane is over your head and nobody really notices ships, but globally it's at least the same as aviation, and it will become increasingly significant.'
Norwegian-based Wilh Wilhelmsen, the world's biggest car shipper, has already asked customers to accept slower deliveries. Ingar Skaug, chief executive, said that dropping average speeds of 18-19 knots by just two knots could save 5 per cent of fuel use and emissions alone.
Kelly will call for a global emissions trading system under which the industry is set emissions caps and must pay for excess carbon emissions. 'Such a scheme would provide incentives to the industry to improve the carbon efficiency of ships and ensure reductions in emissions were achieved at minimum cost,' she will tell the International Maritime Organisation's 167 national members.
The IMO said an emissions trading scheme was being discussed by special working groups. But Lee Adamson, the organisation's head of public information, said the agency wanted control of any system because, if it was part of the UN's Kyoto Protocol, many major shipping nations would not take part.
Friends of the Earth welcomed Kelly's move, but warned that the UK still needed to include international shipping in targets to cut national emissions in the Climate Change Bill. Last week, Hilary Benn, the environment secretary, rejected a Lords amendment that would have committed the government to include aviation and shipping in domestic targets.
A separate IMO meeting this week will discuss proposals that hark back to more romantic images of life on the ocean wave - including 'kite' sails to harness wind, 'sails' of solar panels and sleeker designs to reduce drag in the water. British Shipping, the industry's trade body, said kites and sails were being tested but it was 'early days'. 'Although they would dramatically change the appearance of some ships, we will not see a return to the beautiful but dangerous days of sail,' added Jeremy Harrison, head of communications. Reduced congestion at ports would also cut emissions, he added.
