asked Her Majesty's Government:

What assessment they have made of the extent to which transport by sea is likely to affect global warming.

My Lords, estimating global greenhouse gas emissions from shipping is challenging due to a lack of data and scientific uncertainty on overall impacts. However, the International Maritime Organization estimates annual carbon dioxide emissions from international and domestic shipping at approximately 1,019 million tonnes, which is 3.3 per cent of total global emissions. Work is continuing to estimate the global climate impacts from the emission from ships of black carbon and nitrogen oxides, which are more uncertain.

My Lords, I thank the Minister for that reply. Since more than 90 per cent of world trade is carried by ship, shipping is naturally a large contributor to global gas emissions. On the other hand, it is the most efficient form of transport. In view of the various proposals for regulation that have been put forward, does the Minister agree that a global system under the IMO is likely to be far more effective than a regional system? If one has a purely European system, there is some danger that the competitive position of British shipping, which is of great importance to the UK economy, not least with regard to the balance of payments, could be jeopardised, so any system has to be flag-neutral.

My Lords, as the noble Lord will be aware, the secretary-general of the IMO has stated that he wishes agreement on measures to reduce greenhouse gas emissions from ships to be achieved at the IMO assembly in late 2009. We strongly support that way forward. The most likely scenario for progress within the IMO by 2009 is agreement on a CO2 design index for new ships, as proposed by Japan, along with a voluntary operational CO2 index, a management plan for current ships and a range of voluntary operational and technological improvements so that we get the global approach that the noble Lord seeks.

My Lords, is my noble friend aware of a rather more pressing issue facing the maritime industry, which is a strike called next week by workers in the port of Dover? It will effectively close the port for several days. Given that the Channel Tunnel is working at part capacity and that most of our imports come from the Continent through Dover, what action is my noble friend taking to try to meet the parties to the dispute and resolve it?

My Lords, the industrial dispute to which my noble friend refers is a matter for Dover Harbour Board to resolve. It is a trust port and independent of governments. We are told that the port has detailed contingency plans in place to minimise any disruption to its customers during the strike action announced this week, and I note that the chief executive was quoted yesterday as saying:

"We have put in place a thorough contingency plan with particular emphasis firstly on safety and security, and secondly on maintaining regular ferry services which will ensure the port remains open in the event of any industrial action prior to the implementation of the new arrangements".

My Lords, given the significant percentage figures that the Minister quoted earlier, is it not essential that shipping is included in Europe's emission trading scheme at the earliest opportunity?

My Lords, we are in discussions on that issue but, as I said in an earlier answer, we are also strongly supportive of a global approach to the issue through the IMO and we note that the secretary-general of the IMO is also committed to seeking a way forward on an international basis.

My Lords, if I may also stray very slightly from the Question, will the Minister join me in congratulating the Royal Navy on starting to get to grips with the pirates off the coast of Somalia?

My Lords, I think so.

My Lords, getting back to the Question, I think that my noble friend said that the current rate of emission from shipping is 3.3 per cent of total emissions. What is the rate of growth of emissions from shipping, and can he put that in the context of rates of growth in other industries, especially aviation?

My Lords, the IMO's estimates suggest that the 843 million tonnes of CO2 emissions, which is its base case for international emissions as of 2007, will rise to between 925 million tonnes and 1,058 million tonnes by 2020 and 1,903 million tonnes to 2,668 million tonnes by 2050, which is an average annual growth rate of between 1.9 per cent and 2.7 per cent. I do not have the comparable statistics for aviation to hand, but I will let my noble friend have them.

My Lords, as we seem to be so keen on wind power on land for energy generation, has any thought been given to combining wind power for shipping—in other words, sails—with mechanical power driven by oil?

My Lords, that is a question for my noble friend Lord Hunt of Kings Heath, who knows so much about energy generation from his new departmental responsibilities. I do not have an immediate answer to the question, but I will write to the noble Countess.

My Lords, will the Minister take account of the likely downturn in world trade as a result of the credit crunch, and so on? That will reduce the volume of shipping. My father was a master mariner after the Wall Street crash, when the shipping trade nearly dried up completely—in fact, he lost his job as a result. What impact will the downturn have on global warming, for example?

My Lords, the reason why the IMO has published a range of statistics is to take account of different scenarios for both the growth of shipping and economic growth in the period ahead. I think that the noble Lord would accept that short-run changes in economic growth do not avoid the need to take action in respect of changes in greenhouse gas emissions that may take place over 40 to 50 years.

My Lords, pursuant to the Minister's answer to my noble friend Lord Attlee, does he recall that in the last quarter of the 19th century, the Royal Navy swept slave trading from the waters off east Africa?

My Lords, I do indeed recall that.