Select Committee on Environmental Audit Written Evidence


Memorandum from the Centre for Aviation Transport and the Environment (CATE)


  A fuller description of the Centre for Aviation Transport & the Environment (CATE) can be accessed at CATE is a multi-disciplinary research centre based in ARIC, at Manchester Metropolitan University. CATE's mission is to facilitate the integrated social, economic and environmental sustainability of the aviation industry through critical research and analysis, and through knowledge transfer between the academic, industry, regulatory and NGO sectors. It operates the multi-sector network SCAN-UK (Sustainable Cities and Aviation Network), which brings together aviation professionals, academics and NGOs for mutual information on the subject of aviation and sustainability (please see

  Dr. Paul Upham is a Research Associate in CATE and has researched and published aviation in relation to sustainability since 1999. His MSc thesis critiqued extended cost benefit analysis as a policy tool for environmental protection and his PhD thesis assessed business the Natural Step sustainability theory. With colleagues he has recently published an edited collection on the subject of aviation and sustainability, addressing social, economic, environmental, technological and political aspects: Upham, P., Maughan, J., Raper, D. and Thomas, C. (eds.) (2003) Towards Sustainable Aviation, Earthscan, London (


  This memorandum supports the concerns of the Environmental Audit Committee that use of monetarised externalities with the current typical range of values is unlikely to align aviation with sustainability conditions. The author has not conducted econometric modelling to support this view, but rather points out relevant principles and facts to support its probability. The subsections in bold below follow the questions asked by the EAC.

1.   Problems with pricing externalities

  1.1  There are good reasons to be cautious about relying heavily on monetarisation of environmental impacts in aviation and other policy domains. Monetarisation of non-marketed phenomena for policy use is particularly inappropriate in the case of irreplaceable environmental systems (Daly and Cobb, 1989). Use of surrogate market values (such as the damage cost approach, which uses the market cost of repairing environmental damage as an indicator of the full cost of that damage) may in my view legitimately inform policy. However, neither this nor monetarized measures of the willingness to pay to avoid or accept damage are appropriate for valuation of systems that people cannot live well without. Relative climate stability is such a system. The same principle applies to particular levels of local environmental quality, such as a healthy level of air quality and a quiet environment. Such a judgment gives priority to the environmental conditions of a healthy life, over what are here considered to be the secondary benefits of leisure travel (the large majority of flights are for leisure purposes).

  1.2  Although the attraction of monetarisation and extended CBA as a decision-making method is understood, it is not a reliable means of policy making and the method should at best inform, not determine policy. A healthy environment should arguably be sought for its own sake and for the benefits this brings, not on the condition that its monetized benefits exceed monetized costs. Environmental policy objectives should continue to be informed by a combination of the values of the electorate, environmental science, technological capability and regulator judgement. While this is imprecise and is subject to political lobbying, as a variant on the traditional approach to policy making it remains preferable to risking further damage by underestimating the value of critical environmental systems in valuation surveys.

2.   DfT estimates

  On climate change, that DfT state that their illustrative cost of £70 per tonne of carbon value takes no account of climatic, social and long term uncertainties underscores the unreliability of externality valuation in policy determination. Exclusion of uncertainties is understandable and in this case probably unavoidable, but it renders the resulting values at best informative, and more likely misleading. When the uncertainties involved potentially pose major challenges to the continuance of a relatively civilised social order, their exclusion from the decision-making calculus is nonsensical and downright dangerous.

  On local air quality, DfT should better explain apparent disparities between the implied COMEAP valuations and those of CE Delft. COMEAP appears to be a significantly more conservative in its standards of evidence.

3.   Environmental policy objectives

  3.1  Paying for monetarised environmental costs is not an adequate environmental policy objective for aviation, but an expedient one that gives the appearance of fairness and analytic rigour, while permitting on-going growth.

  3.2  Knowledge of the environmental and human effects of ecological and human exposure conventionally plays an important role in the targets and limits set by environmental regulation. The problems with cost internalisation as a policy principle are that (a) it is not adequately achievable in practice due to imperfect knowledge, and (b), as a result of this there is no guarantee that internalised costs will protect required environmental quality states.

  3.3  A more reliable policy is to define such environmental quality states and the emissions limits and/or levels of human activities that affect them, and regulate directly for their achievement. This is typical objectives-oriented environmental policy. Such an approach influences related prices, which in turn influence related demand. However, the approach relies not on price as the originating control mechanism, but on regulator judgement determined by environmental legislation and associated quality standards.

  3.4  Regulatory approaches and market approaches need not be mutually exclusive, but market approaches should be used primarily to achieve improvements within a regulated framework. They should not be relied on to determine the direction and extent of improvements. For this, public regulation of transport infrastructure is necessary (some possible forms of which in relation to aviation are mentioned below). Moreover, market approaches are much wider in scope than monetarisation.

  3.5  The Government's policy objective of (nominal) externality internalisation is reasonably consistent with its aim of maximising social and economic benefits. However, minimisation of environmental impacts is not what the Government really means; what it means is mitigation to a level at which environmental impacts are politically tolerable. Environmental impact minimisation would involve at least ecological enrichment of airport sites and zero fossil-fuelled flights. It is not a policy objective that is commensurate with maximisation of social and economic benefits.

4.   Justification for supplementary policy measures: CO2

  4.1  In 2000 (Valuing the External Costs of Aviation), DfT estimated that internalising the total environmental costs of aviation would add about £3 to shorthaul passenger costs and £20 per longhaul passenger. With an average demand elasticity of -0.8, and assuming that the additional costs were fully reflected in ticket prices, DfT state that this would reduce demand by 3% and 5% respectively. These estimates include a carbon-tonne value of $80 and are for the year 2000.

  4.2  In 2002, DfT (Aviation and the Environment: Using Economic Instruments) estimated that internalising the costs of climate change alone would reduce demand for air travel by 10% of what it would be (by 2016 and continuing until the end of the study period at 2030).

  4.3  In 2002, DfT observed in the RASCO Final Report that a 10% reduction in national demand in 2030 would be equivalent to only 50% of the difference between the mid point and the lower end of the range in the DETR Air Traffic Forecasts (2000).

  4.4  In contrast, the 2003 UK energy White Paper admirably sets a target of reducing total UK carbon emissions by 60% by 2050. This echoes the analysis of the Royal Commission on Environmental Pollution (RCEP) in their twenty-second report Energy—The Changing Climate. This argued that a "contraction and convergence" policy was required for international control of carbon emissions, a consequence of which is a requirement for a 60-90% reduction in carbon emissions by industrialised countries. The overall objective is to avoid "dangerous climate change" by achieving a global mean atmospheric concentration of 550ppmv or less for carbon dioxide, a threshold that some argue is still too high.

  4.5  This section uses Government emissions statistics and projections to estimate aviation's projected emissions share. Lines h-j present the final estimates.
a. UK total CO2 in 2001: 572 million tonnes(156 MtC) [1]
b. UK projected total CO2 in 2020:495 million tonnes (135 MtC) [2]
c. UK projected total CO2 in 2020 CL): 576 million tonnes(157 MtC) [3]
d. UK projected total CO2 in 2020 CH): 569 million tonnes(155 MtC) [4]
e. UK aviation CO2 in 2000:30 million tonnes (8 MtC) [5] 5-6% of UK total
f. UK projected aviation CO2 in 2020: 55 million tonnes(15 MtC) [6] 9.5-11% of UK total
g. UK projected aviation CO2 in 2030: 77 million tonnes(21 MtC) [7] 13-15.5% of UK 2020 total

h.  Accounting for radiative forcing uplift (x 2.7) for UK aviation CO2 gives 80 million tonnes[8] for 2000, which is some 14% of the UK total for that year.

i.  Accounting for radiative forcing uplift (x 2.7) for UK projected aviation CO2 in 2020 gives 148 million tonnes[9], which is some 26% of the UK total for that year[10].

j.  Accounting for radiative forcing uplift (x 2.7) for UK projected aviation CO2 in 2030 gives 208 million tonnes[11], which is some 36% of UK total for 2020[12]. (A 2030 projection for total CO2 is not provided by the DTI; the 36% figure can be taken as illustrative only).

  4.6  A projected CO2 share for aviation of some 26% in 2020 and perhaps 36% in 2030 is substantial (huge?), given that aviation is but one component of one economic sector (transport). The 2030 projection for uplifted aviation CO2 represents an increase of over 2.5 times that of 2000.

  4.7  However, the even greater significance of projected trends for "unconstrained" aviation growth becomes most apparent when seen in the context of the 60% reduction in national CO2 by 2050 that the energy white paper acknowledges as necessary (Our Energy Future—creating a low carbon economy). A 60% reduction total UK CO2 from the 2001 level would be 343 Mt, to be met by 2050. If aviation were allowed to grow as DfT anticipate, by 2030 its share of the UK 2050 CO2 target would, at 208 Mt, be some 60%. While it is possible that society may want to use its international CO2 share in this way, partly because surface sources of greenhouse gases are in principle more amenable to replacement with low carbon energy technologies, the allocation should be discussed rather than assumed.

5.   Justification for supplementary policy measures: local impacts

  5.1  This section summarises the following paper, which should be seen for references and supporting tables:

  Upham, P. (2002) "UK Regional Air Services Consultations: a summary of and commentary on the RASCO Reference Case", World Transport Policy and Practice, Volume 8, Number 4, pp. 39-46. Freely available as file WTPP-8-4.pdf at—index.htm

  5.2  Regarding noise exposure assessment, the 57dBA contour should be used as a key measure, being the commonly accepted standard (including by DfT) for the onset of "significant community annoyance".

  5.3  Use of the 57 dba Leq noise exposure contour as a key decision-making criterion, however, would lead to some unpalatable implications for the Government, particularly in conjunction with some of the other consequences of expansion. Firstly in the SE, Heathrow already causes officially defined noise annoyance (57 dba Leq) to a large population of 300,000 people. While a new runway would increase this noise exposure by "only" 8%, the most optimistic aircraft technology assumptions would still leave 5,000 residents exposed to excess NO2 by EU standards (DETR, 2000). When serious concerns over the underlying aquifer, excess water demand and consequences for nearby water-courses are added to this (DfT, 2002g, p.53), the environmental case against a third runway looks strong.

  5.4  This case would be further (though unnecessarily) strengthened by a decision to significantly develop Stansted, which could in time take the bulk of new SE traffic. Regarding Stansed, two new runways would lead to significant new urbanisation (an additional 144,000 jobs) in a region that is not in particular need of development, and it is not at all clear that the fears for Heathrow's hub status are sufficiently grounded to justify this.

  5.5  Secondly, the noise impacts of a new wide-spaced runway at Birmingham airport, necessary to meet RASCO level demand, are high at 144,000 to 83,000 additional people (57 dba Leq contour), depending on technology assumptions. While the Midlands region in general would benefit from the additional 14,000 jobs, these would come at the cost of more than a 200-400% increase in the population exposed to "annoying" noise.

  5.6  Thirdly, in the North of England, additional air traffic in the RASCO scenario would bring relatively low numbers of additional people under the >57 dba Leq contour if the -14dba assumption can be realised. Even then, Manchester Airport would continue to expose the current substantial number of over 43,000 people to >57 dba Leq.

  5.7  In summary, on the basis of the RAS consultation projections, even under the politically challenging assumption of significant technological improvement by aircraft (-14dba on present "Chapter 3" standards), enforcing a rule of no additional daytime residential exposure to >57 dba Leq would prevent the infrastructure expansion necessary to meet reference case demand at Heathrow, Stansted, Luton and Birmingham, with lesser problems at Liverpool John Lennon and Newcastle airports.

  5.8  In fairness it should be pointed out, though, that with a threshold of >60 dba Leq (30% more averaged sound energy), the noise-based case against expansion at these airports is less clear-cut. The population exposed to > 60 dba Leq would increase over seven times around Stansted and by a worrying 13 times at Birmingham. Yet exposure around Luton airport could decrease under technologically improved conditions and should decrease under standard technological conditions at Heathrow.

  5.9  DfT (Aviation and the Environment: Using Economic Instruments) estimate the total cost of noise impacts for all airports at around £25 million for 2000, with a cost at up to 40 pence per passenger (based on SE values). It is difficult to imagine an additional 40 pence on a ticket price having more than a negligible effect on demand. For this reason and those above, we need more than cost internalisation to control aviation impacts.

6.   "Practical" policy options

  6.1  The value of pragmatism and practicality is understood, but how practical should we seek to be in this case? Are modest changes to "business as usual" policies that risk the loss of the Atlantic Conveyor maritime current practical or irresponsible? Scientifically, one must agree with the RCEP in their special report The Environmental Effects of Civil Aircraft in Flight, that the potential climatic effects of aviation trends are disturbing.

  6.2  What is more debatable is the extent to which aviation should be required to respond relative to other sectors. Road transport has a higher adverse climatic effect and exposes millions more people to annoying levels of noise than do aircraft. This needs to be borne in mind when developing policy proposals, but should not be used as an excuse for inaction.

  6.3  IPPR's Sustainable Aviation 2030 and the forthcoming POST report Aviation and the Environment point to specific areas of regulatory deficit relating to UK aviation. The Aviation Environment Federation is also very capable of preparing a practicable list of near-term policy recommendations. The AEF are involved in several aviation policy processes and have a moderate political stance. They know a great deal more about the near term and local issues than I do.

  6.4  Therefore I will restrict my policy comments to those that others are less likely to make. The Energy White Paper target of a 60% reduction in carbon dioxide by 2050 needs to be taken seriously (by all industrialised countries) if we are avoid serious climatic disturbance in the next 100-300 years. The Government should revisit RCEP's twenty-second report Energy—The Changing Climate and use it to develop specific policies and targets that can make the aspirations in the White Paper a reality.

  6.5  The Government needs to take an informed decision on aviation's importance relative to other sectors. How much growth in aviation radiative forcing is to be permitted, if any, at the expense of other sectors that may more easily turn to renewable fuels and energy efficiency? CATE will shortly begin a one year research project with the Tyndall Centre (UMIST) that will assess some simple scenarios in this regard. It can be hypothesised that it is unlikely that the radiative forcing implications of the tripling of air passenger demand envisaged by DfT could be readily accommodated alongside the competing demands of other economic sectors. A corollary of this would be that not all of the infrastructure required for the mid range RASCO scenario would be necessary. For reasons of inter-regional equity, it may well be desirable to permit growth in air travel in the regions rather than the SE.

Selected references

  Daly, H. and Cobb, J. (1989) For The Common Good. Redirecting the Economy Toward Community, the Environment, and a Sustainable Future, Beacon Press, Boston.

  Upham, P (2001) "A comparison of sustainability theory with UK and European airports policy and practice", Journal of Environmental Management, vol 63 (3), pp. 237-248

April 2003

1   Source: Table 1.2 "Estimated emissions and removals of greenhouse gases on an IPCC basis: 1990-01 (2002 provisional)", Digest of Environmental Statistics, March 2003, Department for Environment, Food and Rural Affairs, Back

2   Based on paragraph 3.11 of DfT's Aviation and the Environment: Using Economic Instruments.  Back

3   CL: Central GDP assumption, Low energy prices, CH: Central GDP assumption, high energy prices. Table 7.1 "UK CO2 Emission Projections (MtC)", Energy Paper 68: Energy projections for the UK, DTI,114 Back

4    Back

5    Back

6    Back

7   From Table D13 in DfT's Aviation and the Environment: Using Economic Instruments. Surface access has been excluded to provide a conservative result. The High Capacity scenario is chosen because it corresponds to the mid-range RASCO scenario. Back

8    Back

9    Back

10   Calculated as a percentage of the CL scenario above, to help provide a conservative estimate. Back

11    Back

12    Back

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