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Climate Change Bill [Lords]

I will do just that and avoid discussing with the hon. Member for Cambridge (David Howarth) my experience of Cambridge, which was splendid. I instead return to the measure before us, which asks the Committee on Climate Change to assess the cost of including aviation and shipping in the Bill. However, the new clause does not say how those assessments are to be made. We must assume that they are to be made on the basis that Lord Stern used to assess the costs and benefits in the report to which the right hon. Member for Scunthorpe (Mr. Morley) referred, or on the basis used in the impact assessment that the Government put before the House, although that assessment refuses to give us any costings specifically on aviation and shipping. It is interesting that the impact assessment totally contradicts Lord Stern, who said that the costs of the measure, including aviation, would be far short of the benefits. Of course, he only reached that conclusion by discounting the future at such a low rate that the benefits exceeded the costs. According to Nordhaus, the leading valuator of this sort of methodology, half the benefits that Sir Nicholas Stern takes into account will not occur until after the year 2800, but so low is his discount rate that they outweigh the costs that we will incur in this century. More sensibly, the Government rejected that. I asked them what interest rate they think should be used, and presumably want to use, in the assessments that they require in new clause 15. They say that they are using the traditional, conventional discount rate required by the Treasury of 3.5 per cent. in real terms. That is why their calculations show that the costs are not necessarily much lower than the benefits, and could well be twice as great as the benefits. Presumably, if the Committee follows the Government's methodology, it could reach the same conclusion for aviation and shipping.