Last autumn, the Environmental Audit Committee warned that the Department for Transport's plans to expand airport capacity would "wreck" the Government's long-term ambitions to reduce greenhouse gas emissions (ENDS Report 343, p 33 ).
The warning made little impact on the aviation White Paper, which opened the door to a large-scale expansion in airport capacity with few concrete measures to curb the industry's soaring climate change impacts (ENDS Report 347, pp 42-43 ).
The Audit Committee has returned to the fray with a damning follow-up report. "Despite protestations to the contrary, it is abundantly clear that the aviation White Paper adopts a 'predict and provide' approach," the MPs conclude. "The DfT has forecast future demand and then provided the framework to meet practically all of it."
The Committee bridles at Ministers' claims that curbing demand would "price people off planes". They point out that passenger numbers are forecast to increase by 4% per year for 30 years - fuelled by a 40% decrease in fares over the same period - and deny "emphatically" that they are seeking a "hairshirt approach".
In a direct challenge to the DfT's approach, the Committee calls for a formal statement of what sustainable consumption means in the context of air travel. It points out that the Government is campaigning to promote changes of behaviour in terms of car use - and asks the DfT to "set out what policies it is pursuing to discourage unnecessary air travel."
The White Paper's only prescription for addressing aviation's climate change impact was a pledge to push for the sector's inclusion in the second phase of the EU emissions trading scheme from 2008.
The Committee is "astonished that the DfT appears to have done no research on some of the key issues which need to be resolved". The MPs were also left with the impression that "discussions have barely started" at EU level - and cast doubt over whether sufficient time, consensus or political will exist to resolve "complex and contentious issues" in order to bring aviation into the trading scheme in 2008.
The first issue concerns the allocation of aviation emissions between Member States - a topic that the MPs expect to "provoke fierce debate". The Committee notes "a certain irony in the fact that the DfT has argued how economically beneficial it is for the UK to host such a large percentage of international flights, when it may well effectively be penalised for this under an ETS and have to make a correspondingly larger cut."
The second key issue is the treatment of aircraft emissions of water vapour and oxides of nitrogen. The precise impact of these emissions remains uncertain, but they are thought to increase aviation's global warming impact to 2-4 times that of CO2 alone. British Airways has argued that only CO2 should be brought under the trading scheme - but the Committee says that this "would flout the precautionary principle".
It is also far from clear how stringent any cap on aviation would be. The MPs note that the knock-on impact on other sectors of the economy could be "immense" - but that neither the DfT nor the Environment Department (DEFRA) is doing any work to model such cross-sectoral impacts.
In the medium term, at least, the Committee finds it "inconceivable that any emissions trading system could generate sufficient credits to allow aviation to expand as forecast, while at the same time delivering carbon reductions of the order needed. The price of carbon could, in such circumstances, go through the roof - provided there was sufficient political will to maintain targets and enforce penalties."
Another issue not addressed by the report is that the emissions trading scheme would almost certainly cover only flights between destinations in the EU. As a result, a very large proportion of emissions from UK flights would be subject to no constraints.
The only action proposed by the Government to deal with flights outside the EU was to continue to push for an open emissions trading scheme through the International Civil Aviation Organization. A DfT official told the Committee that the UK was "ploughing a pretty lonely furrow" in its advocacy of emissions trading - leading the MPs to conclude that the likelihood of ICAO making any significant progress is "remote".
The Committee finds it "regrettable" that the Government has not promoted an interim emissions charge, or considered the case for levying VAT on air tickets. It believes that this approach could "offer the scope for flexible adoption by like-minded Member States", and would be more practical than the "all or nothing" emphasis on emissions trading.
The MPs also restate their concern that the growth in aviation emissions will make "meaningless and unachievable" the Government's aspiration that the UK's CO2 emissions should be reduced by 60% by 2050.
The Government maintains that because no agreement has been reached on how to account for international aviation, the 60% target applies only to "domestic" emissions. However, the Committee warns that the Government should stop attempting to argue that aviation "must remain a special case".
The White Paper offered a reduced forecast of aviation CO2 emissions for 2030. Even using this figure, aviation's contribution to the UK's future climate change impacts is very considerable (see table). The MPs suggest that "the most we could hope to attain" would be a reduction in emissions of "about 35%".
In fact, the picture could be even worse. In late February, the DfT released a document on aviation and global warming.2 This revealed that its revised "central" emissions forecast is not far from its "best case" scenario - confirming the Committee's view that the DfT is making "optimistic assumptions" about technological improvements. Under a worst case scenario, however, CO2 emissions in 2030 and 2050 would be 18% and 67% higher than in the central case.
The Committee blasts the "poor quality" of the White Paper's appraisal of aviation's climate change impacts. The new supporting paper is "opaque and unhelpful" and "shows some signs of having been prepared in a hurry" - leading MPs to suggest that it may not have been "fully available" when key decisions in the White Paper were being made.