The government yesterday outlined a range of measures designed to curb carbon emissions from international shipping, including plans for an international cap-and-trade scheme and the imposition of speed limits for some ships.

Speaking at an event to mark the 60th anniversary of the International Maritime Organisation (IMO), transport secretary Ruth Kelly recognised the shipping industry's status as the most carbon efficient means of transporting freight, but warned that with the sector accounting for an estimated 4.5 per cent of global emissions, more needed to be done to reduce its environmental impact.

She stopped short of endorsing plans currently being discussed in Brussels to include shipping in the European Emissions Trading Scheme (ETS), instead insisting that a global cap-and-trade scheme for the sector would be required. She said that such a scheme would put a price on carbon and as such give the industry an incentive to improve the carbon efficiency of ships.

The comments were welcomed by Rob Ashdown, manager of environment affairs at the British Chamber of Shipping, who agreed that a global scheme represented the best means of cutting emissions given the international nature of the industry, adding that work being undertaken by the IMO to develop a strategy for cutting emissions as part of the UN's plans for a post-Kyoto deal represented the best means of developing a globally consistent legislative framework.

Kelly also called for the wider deployment of cleaner engine technologies such as fuel cells and urged shipping companies to make operational improvements "like slowing down ships to maximise fuel efficiency".

Several major operators have already adopted the approach as a means of addressing soaring fuel bills. Norwegian-based Wilh Wilhelmsen, for example, has already cut speeds claiming that by dropping average speeds by just two knots its could reduce fuel use and emission by five per cent.

Ashdown added that "better weather routing, continuing design improvements and reducing port congestion" could also play a key role in cutting emissions in the future.