Agenda Item 12
AVIATION AND CLIMATE CHANGE
Background
1.
For several years now we have reported on the steps being taken both in the UK
and in Europe to deal with the impact of aviation emissions on climate change.
Chief among the ideas for dealing with this issue is the proposal to extend the EU
Emissions Trading Scheme (EU-ETS) to include emissions from aviation. In this
paper we report on the progress of this proposal but also on the recent sharpening
of public awareness of the climate change issues and perceptions as to how far
aviation contributes to this
A Hot Issue
2.
Since the last meeting there has been a huge escalation in public awareness and
concern about climate change and the issue is now centre stage in the media.
Against this background aviation is firmly in the spotlight and given the coverage it
receives it would be surprising if emissions from aircraft were not perceived as
already the primary cause of climate change! Looking back through the output of
the UKACCs news service media:
•
In December 2006 the Chancellor doubled Airport Passenger Duty.
Environmental protection was cited as the justification for this although many in
the industry are not so sure – they believe this was a convenient excuse for
what was essentially a tax gathering measure. The tax has certainly been
controversial. It applies to tickets already purchased and this has given rise to
litigation and another case has been launched on the basis that the tax
infringes human rights (i.e. the right of people to leave the country)
•
In January the Conservative Party joined the fray suggesting that domestic
flights should be taxed heavily with the money used to improve the railways so
that in five years' time everyone is choosing to go by train within the UK. And
in March the Party announced proposals to levy VAT or fuel duty on domestic
flights, or a per-flight tax on airlines, and also a green air miles scheme under
which passengers would be issued with a 'green miles' allowance and forced to
pay more if they took extra flights.
•
“Carbon offsetting” has become one of the most popular means of attempting
to neutralise CO2-generating activities such as flying. It allows consumers to
contribute to projects such as tree planting to negate the effect of their flights.
As mentioned in the paper on the Air Transport White Paper Progress Report,
the Government will shortly be bringing forward proposals to make it simpler for
air passengers to offset the carbon emissions arising from the flights that they
take by setting out a government standard for how such schemes should
operate.
•
A Government standard is important. At the end of April EasyJet said that the
carbon offsetting market is riddled with 'snake oil salesmen' determined to
make excessive profits from green-minded air travellers.
•
There is a new focus among the airlines on newer aircraft, better engines and
bio fuels.
1
3.
In this atmosphere is difficult sometimes to sort fact from hype and, more
importantly, what can be done at a local level to make a real contribution in dealing
with the climate change issue. With this in mind the Technical Adviser to the
Gatwick Airport Consultative Committee, Ros Howell, drew up the attached paper
for the committee to consider at its April meeting. The paper was very well received
by all interests serving on the Committee as it presented a balanced view on this
important issue. A key message arising from the debate at Gatwick was that in
considering statistics and data on global warming it was important to compare like
with like. Many publications on the subject failed to clarify this particular aspect and
the paper gave examples on the differences in the statistics. The Gatwick
Committee also wish to highlight that while airport consultative committees do not
have a global remit they can seek to influence the debate within the UK, i.e. through
the responses submitted to national and European consultations, and the
implementation of measures at their airports to address climate change concerns.
Airport Consultative Committees may therefore find the attached paper a useful
brief for a discussion at their meetings.
The European Emissions Trading Scheme
4.
Against the frenzy of media activity the work goes on to secure the inclusion of
aviation emissions in the EU Emissions Trading Scheme. From last year’s
European Update 1 members will recall that the proposal was debated at a meeting
of the EU's Council (Environment) on 2nd December 2005. The meeting felt that,
from an economic and environmental point of view, the inclusion of the aviation
sector in the EU Emissions Trading Scheme seemed to be the best way forward not
least because emissions trading is already operating within the EU and also
because it held greater potential for application internationally than other policy
alternatives. The meeting therefore urged the Commission to bring forward a
legislative proposal which was both environmentally meaningful and economically
efficient.
5.
On 20th December 2006 the Commission published its proposal for legislation 2 . It
provides for aviation to be brought into the EU ETS in two steps. From the start of
2011, emissions from all domestic and international flights between EU airports
would be covered. One year later, at the start of 2012, the scheme would be
expanded to cover emissions from all international flights – from or to anywhere in
the world – which arrive at or depart from an EU airport. The intention is for the EU
ETS to serve as a model for other countries considering similar national or regional
schemes, and to link these to the EU scheme over time. The EU ETS scheme might
thus form the basis for wider, global action. Depending on how long implementation
in European and national legislation takes, the proposal “should take-off during the
second phase of the ETS (2008-2012), perhaps in 2010”.
6.
On 30th March 2007 the UK Government launched a consultation on the
Commission's proposals and on the Government’s initial analysis of the changes
required to them. The comments received would guide the UK Government’s
negotiating position. Details of the consultation document and associated papers
were circulated to all members. They can also be seen on the DfT's website 3 . The
closing date for comments is 1st June, 2007.
7.
The EU’s proposals will have an impact on airlines flying to and from other
continents. In this connection it needs to be noted that in January a U.S. diplomat
1
http://www.ukaccs.info/06almfiles/06euroroundup.doc
http://ec.europa.eu/environment/climat/pdf/aviation_ets_com_2006_818-21273_en.pdf
3
http://www.dft.gov.uk/consultations/open/aviationemissionstrading/
2
2
warned the European Commission against adopting rules that would impose
emissions controls on all flights within and coming into Europe noting that the US
could take legal action if the measure were signed into law. Calling the proposal
"unworkable and unlawful," the diplomat said the US objected to the unilateral
nature of the plan, which would force foreign airlines flying in Europe to pay for
carbon dioxide emissions. It was “the antithesis of a global solution to what is a
global problem”.
8.
There has also been criticism that the scheme will allow the airlines to make
windfall profits. In December the Chairman of the Commons Environmental Audit
Committee, said the Committee was preparing to launch an investigation into the
potential for airlines to cash in on tradeable carbon emission credits.
Environmentalists claim airlines stand to make windfall profits of nearly £2.5bn as a
result of the proposal to give away most emissions permits rather than auction
them. This is disputed by the airlines. In a press release EasyJet said that all other
sectors that participate in the Emissions Trading Scheme have had permits
allocated to them and the only way an airline could make windfall profits of the sort
envisaged is by ceasing to operate. “This is unlikely to be a strategy that is
approved by the shareholders of any company”.
Conclusion
9.
The Secretariat will continue to keep members up to date on these issues and in
particular on the progress of the proposal to secure the inclusion of aviation
emissions in the EU Emissions Trading Scheme
Stuart Innes
May 2007
3
Agenda item no. 8
GATWICK AIRPORT CONSULTATIVE COMMITTEE
19th APRIL 2007
AVIATION & GLOBAL WARMING
REPORT BY THE TECHNICAL ADVISOR
1
INTRODUCTION
1.1 For every claim or statistic about global warming and climate change it seems
there is an opposite view or different figure. The subject is complex and it is not
surprising that the statistics and supporting numbers and arguments can seem to be
at odds when often they are not. Much of the technical information is based on truly
leading edge science and many of the economic calculations are similarly breaking
new ground.
1.2 In order to understand the complexities of the subject and, especially, the
statistics, it is important to compare like-with-like since failure to do so is often at
the root of apparently diametric claims using the same data sets. Unfortunately,
many of the papers on the subject fail to clarify this particular aspect.
1.3 This paper sets out to identify the main elements of the climate change debate
as they appertain to aviation and to attempt to clarify some of the misconceptions in
order to provide a clearer view of the main points of the argument.
2
BACKGROUND
2.1 There have been discussions at previous meetings of both the General Purposes
Sub Committee and plenary GATCOM where members have discussed the
ramifications of climate change and the part played by aviation. Some of the
discussions have been side-tracked by disparities between the various figures quoted
and their degree of relevance. As a result, this paper was commissioned to seek to
provide an explanation of why such statistics apparently differed. As with all
statistics, the role of any associated underlying assumptions also needs to be made
clear if the figures themselves are to be used with accuracy.
3
THE SCIENCE
3.1 There is agreement that there is a general warming of the atmosphere. Figure 1
shows the distribution of incoming solar radiation and the associated backscatter,
reflection and absorption percentages. It also shows the breakdown of outgoing
radiation in a similar manner.
1
Figure 1: Incoming and Outgoing Radiation
3.2 Aviation contributes to climate change through emissions arising from the
combustion of kerosene, including:
• Carbon dioxide (CO2)
• Water vapour (which leads to the formation of contrails and is believed to
enhance formation of cirrus clouds at altitude)
• Nitric oxide and nitrogen dioxide (NOx) (which forms ozone, a greenhouse
gas, at altitude)
• Particulates (soot and sulphate particles)
• Other compounds (e.g., sulphur oxides, hydrocarbons).
3.3 The impact of aviation on climate change is increased over that of direct CO2
emissions alone by some of the other emissions and their specific effects at altitude.
These effects include increased tropospheric ozone, contrail formation and a small
amount of methane (CH4) destruction.
3.4 The effects of CO2 in the atmosphere are believed to be well quantified. In
contrast, the effects of other greenhouse gases and effects such as contrails and
cirrus clouds generated by aviation are much less well understood. Their effects are
complicated by the differing times they persist in the atmosphere.
CO2
O3
CH4
H20
Sulphate
Soot
Contrails
Long lived, greenhouse gas so warms
Lifetime weeks to months. Product of NOx emissions plus
photochemistry. Radiatively effective at subsonic cruise levels.
Lifetime of ~10 years. Aircraft NOx destroys ambient CH4
Forcing small because small addition to natural hydrological cycle.
Triggers contrails, but actual contrail content is from the atmosphere.
Scatters solar radiation, to space, i.e. cools
Absorbs solar radiation, to space, i.e. warms
Reflect solar radiation, i.e., cools; but reflects some infrared radiation
down to earth, i.e., warms; mainly the latter.
2
Cirrus
Contrails can grow to larger cirrus clouds (contrail cirrus), which can
be difficult to distinguish from natural cirrus. Generally warming
effects.
Measurement of Warming Factors
3.5 Radiative forcing is a direct measure of the instantaneous globally averaged
heating rate arising from a given quantity of a greenhouse gas. Radiative forcing
index figures are frequently quoted in climate change publications, particularly by
governments.
EU and UK policy statements contain phrases such as ‘‘the
environmental impacts of aircraft are thought to be 2–4 times greater than that from
CO2 alone’’. This RFI factor of 2–4 (specifically 2.5) has been used to indicate that
under certain scenarios of both future aviation and other UK emissions, “by 2030
aviation emissions could account for 31% of total UK greenhouse gas emissions”.
3.6 There is a significant problem in the use of the RFI because it fails to account for
the resident timescales of emissions and so it attributes a larger fraction of climate
change emissions to aircraft than is currently justifiable. Most references to RFI are
made in the context of aviation and ignored when attributable to other sectors
emitting GHG. If non-CO2 effects are to be included in emissions trading, then this
should cover emissions from all industries, not just aviation.
3.7 The potential of a particular gas to enhance the greenhouse effect in the future
depends on how the concentration of that gas will change. Global warming potential
(GWP) is a quantity that takes into account four factors:
• Radiative forcing for a known amount of a gas mixed in the atmosphere
(Watts m-2)
• Source (emission) strength of a gas
• Lifetime of a gas in the atmosphere (measured in years)
• Indirect effects of the gas on radiative forcing.
3.8 The GWP is the predicted radiative forcing of the gas on a specified time horizon
– at 20, 100 or 500 years from now. For example, if equal masses of two different
climate change agents with similar RFs were emitted on the same day and one had a
lifetime of a few days and the other over 100 years, the agent with the 100 year
lifetime would obviously have the far bigger impact on climate.
3.9 In the applications by the EU and the UK Government, the factor of 2.5 has
essentially been applied as if it were a GWP. This is incorrect according to Forster et
al (2006). CO2 emitted by aircraft might have a much smaller initial RF than a
contrail, but, crucially, it will remain in the atmosphere many times longer and
continue to give a RF for the next 10–300 years, whereas the contrails and cloud RF
only last for a few hours or days. Most other aircraft related climate effects have
timescales of around 10 days. Aircraft methane’s indirect effect on ozone is the only
other aircraft related climate effect with an appreciable timescale (around 10 years).
3.10 Forster et al (2006) have carried out an illustrative calculation of an ‘EmissionWeighting Factor’, which is an estimate of the total effects of gas emissions and
other physical effects, measured over a specified number of years. They include the
emission of aviation NOx (which acts in a complex fashion, producing a short-lived
increase in ozone, then a longer-term decrease in methane – which is itself
accompanied by a decrease in ozone) and contrails [NB: a very cautious estimate is
used for contrail]. The use of a ‘2.5’ figure will be a considerable overestimate if a
long period is considered.
3
3.11 As well as leading to incorrect conclusions about the total magnitude of nonCO2 effects, the use of RFI rather than an EWF could generate incorrect operational
conclusions. For example, an aircraft flying at a lower altitude burns more fuel - and
so emits more CO2 - but is also much less likely to form contrails. Hence, flying at
lower altitudes could reduce the RFI but would but exacerbate climate change as
measured by the EWF. Thus, operational ‘mitigation’ would actually be adding to
climate warming.
3.12 It must be stressed that GWP is a difficult quantity to predict. Gases have a
complex behaviour of in the atmosphere and there are uncertainties in emission
rates. Indirect effects can be difficult to quantify, e.g. methane. Water vapour and
clouds have feedback effects.
4
THE STATISTICS
Global temperature records
4.1 There are different scientific views on the causes of global warming but the
records show an increasing trend in temperature and other factors affecting the
world’s climate. These figures include (according to recent information from the 4th
IPCC):
• Eleven of the 12 years from 1995 to 2006 have been the hottest since 1850.
• Sea level rose on average 1.9mm a year from 1961 to 2003 but by 3.1mm
from 1993 to 2003.
• Arctic summer ice is seen to be decreasing by more than 7% a decade and
there is some evidence that glaciers are melting in Greenland.
• The range of temperature rise predictions for 2100 is 1.1 – 6.4oC (amended
from 1.4 – 5.8oC).
4.2 In addition, the global temperature record 1856-2005 shows that:
•
2005 was the second warmest year on record, exceeded by 1998.
•
The 1990s were the warmest decade in the series.
• Nine of the ten warmest years have occurred in the past ten years.
• Analyses of over 400 proxy climate series (from trees, corals, ice cores and
historical records) show that the 1990s was the warmest decade of the
millennium and the 20th century the warmest century.
4.3 In its most recent report, the IPPC stated, “most of the observed warming over
the last 50 years is likely to have been due to the increase in greenhouse gas
concentrations.”
Aviation/Air transport Statistics
4.4 Aviation contributes to global climate change, and its contribution is increasing.
The EU's total greenhouse gas emissions fell by 5.5% from 1990 to 2003, but CO2
emissions alone from the international aviation of the EU 25 increased by 73% in the
same period.
4
Figure 2: EU GHG Emissions by Sector as an Index of 1990 levels
180
160
Index 100=1990
140
Int aviation
Energy
Industrial Processes
Agriculture
Waste
Total*
Transport
120
100
* without land use
change and forestry
80
60
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
Year
UK Air Transport CO2 and GHG Statistics
4.5 Aviation CO2 emissions currently account for 1.6% of global GHG emissions.
However, the impact on climate change is greater than these figures suggest
because of other gases released by aircraft and their effects at high altitude. For
example, water vapour emitted at high altitude can trigger the formation of
condensation trails, which tend to warm the earth’s surface. There is also a highly
uncertain global warming effect from cirrus clouds than can be created by
particulates emitted by aircraft.
4.6 In 2050, under “business as usual” projections, CO2 emissions from aviation
could represent 2.5% of global GHG emissions. However, taking into account the
non-CO2 effects of aviation would mean that it would account for around 5% of total
warming effect (radiative forcing) in 2050. The uncertainties over the overall impact
of aviation on climate change mean that there is currently no internationally
recognized method of converting CO2 emissions into the full CO2 equivalent quantity.
4.7 A variety of figures has been quoted in DfT, DEFRA and DTI publications for UK
Air Transport CO2 emissions. One of the statistical problems is that the Kyoto
protocol covers only domestic civil aviation. One authoritative source of data on Air
Transport emissions is the Office for National Statistics (ONS) ‘Environmental
Accounts’. The GHG figures are given as CO2 equivalents, with the other GHG
contributions being converted by use of the GWP figure for the gas concerned.
4.8 The greenhouse gases included in these atmospheric emissions accounts are
those covered by the Kyoto Protocol: carbon dioxide (CO2), methane (CH4), nitrous
oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur
hexafluoride (SF6). To aggregate the greenhouse gases covered in the accounts, a
weighting based on the relative global warming potential (GWP) of each of the gases
is applied, using the effect of CO2 over a 100 year period as a reference. This gives
methane a weight of 21 relative to relative to CO2 and nitrous oxide a weight of 310
relative to CO2. SF6 has a GWP of 23,900 relative to CO2. The GWP of the other
fluorinated compounds varies according to the individual gas.
5
4.9 The Environmental Accounts are published on a National Accounts basis and
differ from the basis used to monitor progress against the Kyoto Protocol in that they
include emissions from international aviation and from fuels purchased abroad by UK
residents, including those purchased by international shipping and aircraft on
international flights. They exclude emissions from fuels purchased in the UK by nonUK residents.
4.10 According to the House of Commons Environmental Audit Committee, transport
is the only sector of the UK economy in which carbon emissions have risen
consistently since 1990. Air travel is the fastest growing source of CO2, with
emissions more than doubling since 1990. Between 1990 and 2004 UK carbon
emissions declined by 5.6% to 152.5MtC; CO2 emissions from international flights
leaving the UK rose by 111% from 4.3MtC to 9.1MtC.
4.11 Aviation’s contribution to carbon dioxide emissions is around 12% of transport
emissions, and 3% of total CO2 emissions. Only 35% of aviation’s climate change
impacts are CO2-related. It is acknowledged to be the fastest growing source of
emissions.
4.12 Globally, international aviation emissions - defined as emissions from any
aircraft leaving one country and landing in another – are about twice as great as
domestic aviation emissions.
Figure 3: UK CO2 Emissions, Air Transport as % of Total
%
Air Transport CO2%
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
9
Year 1990 to 2003
6
10
11
12
13
14
Figure 4: Air Transport Greenhouse Gas Emissions as % of UK GHG Emissions
Air Transport GHG%
8
6
% 4
2
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Year 1990 to 2003
4.13 It should be noted that, according to IATA:
• Over the last 40 years emissions per passenger kilometre have decreased by
70%
• Air transport contributes a small part of global CO2 emissions (2%).
• Airline fuel efficiency improved 20% in the last decade, nearly 5% over the
past 2 years. Today’s modern aircraft consume, on average, 3.5 litres per
100 passenger kilometres. Next generation aircraft such as the Airbus A-380
and Boeing B-787 are targeting fuel efficiencies below 3.0 litres per passenger
kilometre.
• 80% of aviation emissions relate to flights over 1,500 kilometres for which
there are no alternative mode of transport.
• Air transport pays entirely for its own infrastructure. This is a $42bn annual
bill. Airlines pay en route charges, landing charges and parking fees. This is
completely different from both road and rail. Additionally, in Europe every
rail journey is subsidised between €2.4 and €7.4. Every air journey
contributes between €4.6 and €8.4 in government revenues and avoided
expenditure.
• Per passenger-kilometre, air transport uses less than 1% of the land required
for the entire transport network in the EU. When considering European
population affected by transport noise, 7% live around airports, 14% reside
along rail tracks and 79% along roads.
4.14 Research has found that per passenger a journey of 400 miles by air of a fully
laden aircraft would produce considerably less CO2 emissions than would a single car
on 400 miles of road.
4.15 Additional statistics of interest include:
• Europe’s ships contribute around a third more carbon than aircraft.
7
•
•
•
In the EU, demand for air travel is growing at 5% pa on average. In China,
14%, and in India, 15% (albeit from lower base numbers).
The UK generates more flights than any other European country: a fifth of all
international air passengers worldwide are on flights that arrive or leave from
UK airports – hence, aviation makes a proportionally greater contribution to
climate change for the UK than for most other countries.
Even at the lower end of the forecast range, carbon dioxide emissions from
aviation are set to reach 17 million tonnes of carbon (MtC) by 2050. The
higher end of the range is 44 MtC. Meanwhile, the UK is attempting to limit
the carbon emissions of all its activities to 65 MtC by this date. This would
mean that, in order to offset aviation’s emissions, all other sectors of the UK
economy would need to reduce their emissions by 71%-87% instead of the
currently planned and already challenging 60% from 1990 levels. These
forecast figures include improvements that may be achieved through
changes in air traffic management, operational procedures and technological
development. If these do not occur, emissions could be even higher.
4.16 In considering aviation and climate change there are two main areas of impact:
• Aviation in the air, including CO2 and non-CO2 impacts.
• Airport site-related, including aircraft of the ground, energy use in operation,
new infrastructure design and surface transport.
4.17 Since end-to-end (gate-to-gate) air transport emissions need to reflect the
impact of the airport infrastructure, the breakdown of emissions of CO2 related to
BAA sites in 2005-06 is shown in Figure 5. The total of 2.1 million tons is described
as less than 4% of aviation in the air.
4.18 It should be apparent that there are a number of pitfalls in considering the
statistics used in this section, some being:
• Do the figures refer to all aviation (i.e., including air freight and business
flights) or air transport?
• Are they concerning international or domestic flights and, if so, how are they
defined?
• How is “UK aviation” defined (usually just internal UK (domestic) but
sometimes used to describe all flights from UK airports by UK airlines (i.e.
includes international))?
• Are the figures “seat miles/kilometres” or “passenger miles/kilometres”? The
two figures will be the same if the vehicle, whether aircraft, train bus or car,
carries its full complement of passengers but comparisons can be problematic
when the figures are confused.
• Are full costs included (e.g., infrastructure and up-stream CO2 used in
manufacturing and fuel)?
• Does the term “global emissions” refer to all emissions or just man-made
emissions (many natural processes cause emissions of GHG)?
•
Where future percentages are quoted, does this assume the other sectors meet
their targets (for some will not)?
8
Figure 5: Emissions related to BAA sites 2005-6 (Total 2.1 million tonnes)
Aircraft on the
ground
Energy - gas Airside vehicles
Energy electricity
Refrigerants
Surface access by
vehicles
Aircraft auxiliary
pow er units
Supply chain
Water
5 ECONOMICS
5.1 A variety of economic instruments have been proposed to address the impact of
climate change. Primarily, these are:
• To tax emissions with the aim of reducing demand, ensuring that external costs
are internalised or incentivising efficiency improvements;
• To limit emissions directly by allocating emissions permits up to an agreed limit
and allowing industry to buy and sell their permits at a price set by the market;
• To enable passengers to offset the carbon by paying into an established scheme
for an equivalent amount of carbon reduction.
5.2 In more detail, economic instruments could include:
• The taxation of aviation fuel.
• Emissions charging.
• VAT on international air tickets (for which EU action would be required).
• Air passenger duty could be restructured to reflect more closely the global
warming costs, for instance by being levying the duty per aircraft rather than per
passenger to incentivise efficiency and by taxing air freight for the first time.
5.3 It is interesting to note that, with regard to the final point above, the Federation
of Tour Operators (FTO) has launched a legal challenge to the recent doubling of
APD. The organization claims that the way the tax was doubled breached the Human
Rights Act. It also says that the Government is not allowed to charge passengers for
the right to leave a UK airport. The FTO says that the 1944 Chicago Convention on
International Civil Aviation (part of EU law since 2004), only allows the Government
to make charges for providing a service – and that has to be related to costs
incurred. If the tour operators are successful, the Government may have to
withdraw the tax and pay back more than £2bn that has been collected since 2004.
The FTO said that the doubling of APD had a disproportionate effect on tour
operators which, unlike airlines, are largely precluded by law from passing on
surcharges to customers who have already booked.
9
5.4 Also, there is concern that the current method of applying APD penalises all
airlines and aircraft equally when some are more environmentally friendly than
others and APD provides no incentive for airlines to operate the cleanest aircraft.
However, the Treasury view is that the increase in APD will save the equivalent of
three quarters of a million tons of carbon every year by 2011.
Aviation in the EU ETS
5.5 The EC will include aviation in the EU's emissions trading scheme in a phased
manner from 2008. The EU ETS places a total cap on the amount of carbon dioxide
that industries covered by the scheme can emit and allocates allowances to cover
emissions within this. If airlines within the scheme emit more than their allocation of
carbon allowances, they will have to buy an equivalent number of allowances from
the carbon market. Those that emit less – for example, as a result of introducing
more efficient technology – will be able to sell their allowances. Putting a price on
emitting carbon creates an incentive for industry to invest in low carbon technology.
5.6 In December 2006, the EC published proposals for including aviation in the EU
ETS. The proposals aim to:
• Tackle the impact of aviation emissions on climate change, in a cost-effective
manner, ultimately ensuring that aviation contributes to climate stabilisation,
and
• Ensure that the long-term development of aviation is sustainable and that it
meets its external costs.
5.7 The impact on aviation is expected to be some combination of:
• Airlines will have to buy surplus allowances from other industries, thus
bolstering the market for carbon and stimulating reductions in non-aviation
sectors.
• There will be an added economic incentive for airlines to improve efficiency,
e.g.
o More retrofitting technical devices to improve performance.
o Optimising fleet timetables and flight frequencies to cut the number of
empty seats.
• Some impact on ticket prices could affect demand:
o
EC expects the price increases to be modest, varying between €0.2
and €9 per return flight for an individual passenger.
o Demand for air transport continues to grow, but at a slower rate with a
relative reduction of between 0.1 and 2.1% between 2008 and 2012,
compared with predicted business-as-usual growth rate of c. 4% a
year.
5.8 The House of Commons Environmental Audit Committee’s report, The EU
Emissions Trading Scheme: Lessons for the Future (March 2007), supported the
inclusion of aviation in the EU ETS but noted that it would only be effective if the
terms of inclusion were such to constrain and ultimately reverse the rise in aviation
emissions. It noted that the impact on airfares, and hence demand for flying, was
projected to be relatively minor.
Climate change costs per passenger
5.9 The FAA has calculated that, per passenger mile:
• The energy used is greatest in sport-utility vehicles, pick-up trucks and transit
buses.
• Cars and commercial aircraft are roughly equal.
10
5.10 However, when CE Delft compared different forms of travel there were
different conclusions. In their study:
• Coaches performed best
• Next were liquefied gas and diesel-powered cars and intercity trains.
• Long haul flights of more than 1,500 km were 50% worse than petrol cars for
each passenger-kilometre.
• Short-haul flights were three times worse than petrol cars (since a smaller per
centage of time is spent on energy-efficient cruise).
5.11 In the above comparisons, much depends on the assumptions used concerning
occupancy rates, type of vehicle and journey distance. As is the case with all
statistics, the choice of different assumptions will lead to different conclusions.
6 SUSTAINABILITY & CLIMATE CHANGE
6.2
•
•
•
•
•
•
6.2
•
•
•
The Strategy Towards Sustainable Aviation was produced in June 2005. It
presents the strategy developed by the key players in UK commercial aviation
to respond to the challenge of building a sustainable future. It acknowledges
that climate change is one of the most significant challenges facing the air
transport industry and a number of industry commitments have been
developed to meet this challenge. In the first year since the publication of
Sustainable Aviation, progress has been made in a number of key areas,
including:
The launch of major aerospace technology validation programmes for
environmentally-friendly engines and integrated wing, as well as aerospace
innovation networks for aerodynamics and new materials and structures.
The agreement between UK airlines of a common metric and reporting on
aircraft emissions and fuel efficiency.
The establishment by a major UK airline of a voluntary carbon offset
programme to help educate passengers about the carbon impacts of air travel
and the opportunities to help mitigate them.
The assistance of signatory companies to the EC in developing the EU
emissions trading scheme to include aviation.
The promotion of best practice in environmental management by SBAC, the
Airport Operators Association and the British Air Transport Association,
working with signatory companies.
The completion of the Continuous Descent Outreach programme to publicise
and inform airports and airlines about the noise, fuel burn and emissions
benefits of this operating technique.
Further targets include:
Progress towards the 50% fuel efficiency target (per seat kilometre, including
up to 10% from ATM system efficiencies).
Building support and assist policy makers in including aircraft CO2 emissions
in the EU ETS by 2008 as a first step towards a global approach.
Proposing appropriate mechanisms by 2012 for mitigating non-CO2 effects.
6.3 In relation to business reporting, the criteria identified by the World Business
Council for Sustainable Development (WBCSD) allow a logical breakdown of activities
associated with sustainability into three categories:
• Direct – under the control of the business.
11
•
•
Indirect – not under the direct control of the business but can be influenced to
a significant degree.
Indirect other – not under the direct control of the business and less open to
influence.
7 TECHNOLOGY INITIATIVES
7.1 Greener by Design points out that, for a kerosene-fuelled aircraft, reducing CO2
emission equates exactly to reducing fuel burn.
For this reason, given the
significance of fuel costs to the balance sheets of airlines, very large sums of money
have been spent over the years with this aim in mind. The more recent concerns
over climate change will benefit from established programmes to find improvements
in aerospace technology and, in particular, that relating to aircraft engines.
7.2 There are too many examples of technology initiatives to list them in this paper.
Examples include:
• The Clean Sky Joint Technology Initiative: a €1.6bn European 7th Framework
project that aims to demonstrate and validate the future technology designed
to meet ambitious long-term goals of radically cutting noise and reducing CO2
and NOx emissions as set by ACARE. Aware of how radical these cuts need to
be, ACARE has made it clear that any workable outcomes must use
substantial levels of innovation allied with the development of breakthrough
technologies. (The ACARE target of a reduction in fuel burn of 50% between
2000 and 2020 is extremely challenging and described by ACARE as “not
achievable without important breakthroughs, both in technology and in
concepts of operation.”).
• OMEGA (Opportunities for meeting the Environmental Challenge of Growth):
funded by Dti, to ensure that research programmes are established to deliver
better understanding and practical solutions for the short, medium and long
term.
8 THE POLITICAL DIMENSION
8.1 Significant improvements to aircraft technology and operational efficiency are
planned but they will not, alone, be enough to neutralise the effect of increased
traffic. Without policy intervention, growth in GHG emissions is expected to continue
in the coming decades.
8.2
The issue of aviation emissions – or, more precisely, emissions from
international air transport associated with so-called “bunker fuels” has proven to be
politically too difficult to address. This is why they have been excluded from the
range of emissions covered by the Kyoto protocol.
One of the key reasons
preventing integration of these emissions into the Kyoto framework was that it dealt
only with national emissions, i.e., emissions which could be associated with
(originating in) a sovereign state. This proved difficult for emissions from
international air travel with unanswered questions such as, would the state where
the flight originated bear responsibility for the emissions for the whole flight (which
could involve stops en route)? Would such emissions be shared between the states
of origin and destination – and, possibly, intermediate stops even if fuel had not
been uploaded?
12
8.3 International co-ordination on reducing emissions from aviation is important to
avoid leakage of mitigation policies from travellers switching to different carriers, or
air carriers changing their routes, or practices such as “tankering” (bunkering) (i.e.
carrying excess fuel on aircraft to avoid refuelling at airports where fuel taxes are
levied). The UNFCC has requested ICAO to take action on aviation emissions,
recognizing that a global approach is essential and plans are due to be brought
forward at end 2007. ICAO has established a Committee on Aviation Environmental
Protection (CAEP), part of whose work plan relates to climate change emissions.
ICAO has recently endorsed the concept of an ETS for aviation, albeit on a voluntary
basis, and current tasks include developing guidance for states wishing to take
forward emissions trading schemes, as well as developing a better understanding of
the potential trade-offs between improvements in CO2 emissions and the effect on
other environmental impacts.
8.4 The USA has refused to sign the Kyoto Protocol on the grounds that it would
hamper economic growth and give India and China an unfair advantage. [The EU
produces about 14% of the world’s greenhouse gas emissions while the USA
produces more than a quarter]. The American Federal Aviation Administration says
that it has “serious and fundamental questions” about the inclusion of aviation in the
EU ETS and is demanding that it is limited to flights departing and landing within the
EU. It claims that the scheme would breach the 1944 Chicago Convention which
exempts airlines from paying tax on international flights. The EC had previously
rejected the option of limiting the scheme to only flights within the EU because they
account for less than 40% of emissions from all departures
8.5 However, it is the view of the EC that incorporating aviation in the EU ETS is
consistent with the 1944 Chicago Convention and subsequent bilateral air service
agreements. Aircraft must comply with the laws and regulations of the State to/from
which they fly, including laws requiring airlines to report their emissions and
surrender allowances to cover those emissions, as the EC directive does.
8.6 The UK Government strongly endorses action on climate change but believes
that action should take place along with economic development. It therefore favours
approaches which allow economic growth. This approach, which applies to the
economy as a whole as well as aviation, is based on permitting growth where
external costs have been met. In the UK:
• The UK Energy White Paper states that the aviation industry should be
encouraged to take account of, and where appropriate, reduce, its
contribution to global warming.
• The UK Aviation White Paper states that it has “long recognised that the
global exemption of aviation kerosene from fuel tax is anomalous but a
unilateral approach to aviation fuel tax would not be effective in the light of
international legal constraints”.
• The Climate Change Bill was published on 13 March 2007. This Bill:
o Set in statute a long term goal of reducing CO2 emissions by 60% by
2050;
o Established a new independent advisory body, the Carbon Committee,
to work with Government on emissions reduction; and
o Set out improved monitoring and reporting arrangements.
• The Government supports the inclusion of aviation in the EU ETS and has
worked closely with the EU to develop the necessary proposals. A
consultation on the Commission’s proposal to include aviation in the EU ETS
was published by DfT on 30 March 2007 (closing date 1 June 2007).
13
9 THE CHANGING PACE
9.1 The Predict and Decide Study (2006) found that, unless the rate of growth in
flights is curbed, the UK cannot fulfil its commitments on climate change. It
suggested that, if the Government wanted to be confident about achieving its
targets, it has to undertake demand management. Improvements in technology and
air traffic management would have some impact on emissions but would not be
enough on their own. Including aviation in the EU ETS was seen as an inadequate
measure to ensure that the aviation sector contributes proportionately to reducing
the UK’s climate impact.
9.2 The Stern report identified that aviation faces some difficult challenges. While
there is potential for incremental improvements in efficiency to continue, more
radical options for emissions cuts are very limited. The international nature of
aviation also makes the choice of carbon pricing instrument complex. Internationally
co-ordinated taxes are difficult to implement since it is contrary to ICAO rules to levy
fuel tax on fuel carried on international services. The majority of many bilateral air
service agreements also forbid taxation of fuel taken on board. As a result, the
choice of tax, trading or other instruments is likely to be driven as much by political
viability as by the economics. A lack of international co-ordination could lead to
serious carbon leakage issues, as aircraft would have incentives to fuel up in
countries without a carbon price in place. The Stern review on the economics of
climate change has reinforced the need to address global warming and the report
emphasised the need for effective measures and international collaboration, as well
as pointing out that effective early action need not prejudice economic growth.
9.3 A recent report by the Tyndall Centre for Climate Change has revised upwards
by 50% the cuts in greenhouse gas emissions that need to be achieved by 2050. It
reported that the UK could move to a successful low carbon economy but only if
aviation is constrained or the rest of the economy is restructured. The report says
that 90% cuts are needed in the next four years, followed by annual cuts of 9% for
the next 20 years.
9.4 The Eddington Transport Study forecast that the influence of higher incomes and
globalisation would have a large impact on the level of demand for air travel. Air
passenger travel forecasts in the AWP show that, even assuming the introduction of
a carbon charge of £70/tC in 2000 rising by £1/tC per annum in real terms, demand
is expected to more than double between 2004 and 2030. Such increases in the
demand for air transport could result in a doubling of year 2000 levels of aviation
carbon emissions by 2030. Eddington also identified a strong economic case for
additional runway capacity provided that analysis showed a net benefit from
increased airport capacity even if users pay the full environmental costs of their
journeys.
9.5 Recently, the EU’s Environment Council has agreed to cut greenhouse gas
emissions by 20% by 2020. This non-binding agreement is dependent on member
states implementing the mandatory CO2 cap on cars and the inclusion of aviation in
the EU ETS. It will also require the EU to derive a fifth of its energy from renewable
resources and introduce the use of bio fuel for 10% of road vehicles. The EU also
agreed that individual targets would be allowed for each of the 27 EU members to
meet the renewable energy goal.
Friends of the Earth has noted that bold
14
environmental targets, however commendable, could prove meaningless unless they
were binding since countries often flout them with little accountability. It pointed to
a recent European Environment Agency study showing that seven EU countries –
Spain, Austria, Belgium, Denmark, Ireland, Italy and Portugal - were set to miss
their own Kyoto targets.
9.6 Currently, the Government’s estimate is that a cut of 60% is required to avoid a
2oC increase in temperatures by 2050. The recent study concluded that a 90% cut
in emissions is needed. The data suggests that, when emissions from aviation and
shipping are factored in, UK carbon emissions have not fallen since 1990.
10 THE WAY FORWARD?
10.1 Dr John Green, in the 2006 Wilbur and Orville Wright lecture at the Royal
Aeronautical Society, predicted that it could reasonably be expected that by 2050,
aviation fuel burn and CO2 emissions would be down by a factor of three, NOx down
by a factor of ten, contrails down by a factor of ten to 15 and impact on climate
down by a factor of four to eight.
10.2 In order to track such improvements is will be necessary to remove the
frequent confusion over aviation’s current and projected share of CO2 emissions and
climate change impacts caused by:
• Failure to compare like with like
• Claims that the air transport industry is heavily subsidised without assessing
the subsidies or net exchequer contributions of competing modes of
transport.
• Failure to assess the impact of control measures on non-EU nations
• Conflicting views on incorporating aviation into EU ETS: will overall emissions
reduce under the current proposal?
10.3 It would be useful to have a clearly defined set of key statistical definitions and
assumptions that would set the parameters for future discussion and debate and
remove the smokescreen that arises from not comparing like with like.
10.4 There is conflict between the different environmental impacts of aviation and
also between these and economic benefits. A discussion paper issued jointly by the
DfT and the Treasury (Aviation and the environment: using economic instruments,
March 2003) calculates the annual external cost to the UK of its civil aviation as:
noise £25m; local air quality £119m-£236m; and climate change £1,400m. This is
roughly in inverse proportion to public perception, as measured by letters of
complaint.
Actions to address these public concerns are likely to focus on
technological and operational solutions which are counter to lessening the climate
change impacts.
10.5 Public opinion surveys dating from 2002-2006 suggest that support for making
flying more expensive on environmental grounds has grown over time. The most
recent public opinion survey, conducted by Ipsos MORI, found that:
• Support for a policy to constrain the growth in air travel outweighed
opposition, with less than 22% of respondents opposed to such a policy
• There was majority support (about 60%) for airlines to pay higher taxes to
reflect environmental damage, even if this means higher air fares.
15
Technology and the trade-offs
10.6 As Stern and others identify, in the case of aviation there are multiple links
between objectives. One of the ways of achieving CO2 improvements in aircraft is to
increase combustion temperatures in engines. However, this increases the levels of
NOx emitted, an important local pollutant. Other measures to improve fuel efficiency
and CO2 performance, such as reducing aircraft weight, have benefits for local air
pollution. There are also complex relationships between gases emitted at altitude.
For example, modern engines have a greater tendency to produce condensation
trails, which intensify warming effects. Policies to meet air pollution and climate
change goals are not always compatible.
10.7 Total environmental impact can be reduced by setting different priorities in
design. For example, NOx emission can be reduced by reducing engine pressure
ratio and ozone generation can be reduced by optimising design to cruise at lower
altitudes. In both cases, the result is likely to be an increase in fuel burn, CO2
emission and operating cost. Contrail and cirrus cloud formation and ozone creation
might also be reduced by operational measures but at the expense of an increase in
fuel burn. Design or operating measures which increase costs are not likely to be
adopted until there is a regulatory framework or system of environmental charging in
place which puts appropriate weight on reducing impacts other than carbon
emission. Options include:
• New, fuel-efficient aircraft.
• Removal of empty space and use of an all-economy layout to maximise the
number of passengers carried per atm. It should be expected that this would
have a knock-on effect to seat prices since the high ticket prices paid by first
and business class passengers effectively subsidise the economy seats.
• The potential shift of passengers to rail for UK and European travel may
reduce some demand for domestic and short-haul aviation.
Market-based solutions
10.8 Market-based solutions suggested include demand constraint (including a
moratorium on building more runways in the UK), local (airport-based) emissions
charging (with legislation recently strengthened through the Civil Aviation Bill), and
personal carbon-trading allowances.
10.9 Airlines and tour operators could consider building in a climate change offset
cost to fares, possibly with an opt-out option. Airport operators, airlines and tour
operators should be encouraged to incentivise passengers to use sustainable forms
of transport with options for rail or coach tickets (rather than car parking) as part of
the ticket price. A recent investigation by Holiday Which? confirmed that, for
specified medium and long distance journeys within the UK, the journey by train was
more expensive than flying or using a coach. Flying was also the quickest option,
even taking check-in times into account. It considered that this imbalance in fares
does little to promote the use of public transport.
10.10 Emissions trading is the market instrument supported by ICAO, the EU and
the UK Government as well as the UK aviation industry. As discussed earlier, a
consultation on the inclusion of aviation in the existing EU ETS has recently been
published by DfT and legislation is expected to follow. Major issues that will need to
be resolved include the scope of aviation to be included (intra EU or all flights into
and out of the EU), the level of the cap and the system for allocating permits. The
initial view of the UK Government is to support the earliest possible inclusion of
aviation in the EU ETS (with full inclusion as early as 2010).
16
Airspace Management & Design:
10.11
It is predicted that the European Single Sky initiative could reduce
inefficiencies in multi-national ATC provision in Europe by c. 7% (where a 1% saving
equates to 500,000 tonnes of fuel). According to IATA, Europe has the power to
reduce aviation CO2 emissions by 12% by implementing the SES. For example,
there are 34 air traffic control centres in Europe but only one in the USA for a similar
traffic and land size. This leads to inefficiencies and delays. The EC acknowledges,
in the context of the SES, that better air traffic management would cut fuel
consumption by between 6% and 12%.
10.12 Air traffic management changes, allied with operational procedures, could
reduce unnecessary fuel burn and provide earlier benefits than technology
innovations can deliver. Options include:
• Adapting the ATM system to enable contrail formation to be reduced by denial
of critical flight levels and re-routeing.
• Gate-to-gate control, enabling fluid start-up to take-off and the removal of
stacks.
• The investigation of trade-offs between more direct flights (point-to-point)
and fewer “hub-and-spoke” routes.
• Reducing fuel burn on long haul journeys by the use of multi-stage journeys
using medium-haul aircraft – it has been predicted that up to 12% of the
global aviation current fleet’s burn could be saved by using more direct
routes.
• The Functional Use of Airspace & Functional Airspace Blocks which would
allow dynamic flexibility in the use of airspace and so minimise impediments
to more direct routeing and reduce the distances flown.
• Continuous Descent Approach.
Operational options
10.13 The introduction of operational improvements is an on-going process and
scope for further change is both limited and less probable. However, benefits could
ensue from the points below in the longer term if technology innovation contributes
to their feasibility:
• Multi-stage long distance travel, since reports show that a number of shorterrange flights contribute less emission (through using less fuel) than the
equivalent long-range flight between the same points.
• Air-to-air refuelling - to reduce the fuel burn penalty incurred through taking
off with a full load of fuel on board.
• Formation flying – to reduce fuel burn by benefiting by improved lift.
11 CONCLUSIONS
11.1 There is a growing acceptance that some kind of problem exists in relation to
climate change. While there are still differences of opinion among the scientific
community, the significant balance of opinion is that man-made emissions are a
critical part of the problem even if normal global temperature cycles are also
involved.
Statistics show that, whatever the cause, the problem is growing.
Unfortunately, numbers are quoted with confidence when, in many cases, like is not
being compared with like. Additionally, the uncertainty factor associated with
atmospheric science (as high as five), is a point either commonly ignored or poorly
understood.
17
11.2 There are dissenting voices but, on the basis of the precautionary principle
espoused by the Stern Report, the weight of scientific opinion advocates that it would
be advisable to err on the side of caution until the matter is clarified. The aviation
industry itself accepts that it should address its climate impacts. Their proposed
mechanisms focus in the shorter term on emissions trading rather than the demand
constraint proposed by other views.
11.3 Technological benefits have a longer timescale. There is a direct relationship
between the fuel used by an aircraft and the carbon dioxide emitted. Significant
sums of money have been spent over many decades in the attempt to increase fuel
efficiency because of the significance to the cost of airline operations. It is unlikely
that the recent focus on global warming will lead to any greater success in finding
technological improvements. Technology targets and their subsequent benefits are
examples of such positive action but it will be over a decade (2020) before the
forecast delivery of such benefits can begin.
11.4 Earlier actions are necessary in order to manage and mitigate the impacts of
climate change.
It is in these areas that BAA is well-placed to implement and
influence change in this field. Examples include:
• As a member of the consortium that owns NATS UK Ltd, BAA can press for
airspace re-design to reduce the en route kilometerage flown through UK
airspace and the introduction of procedures (gate-to-gate/dynamic en route
flight profiling) to reduce or remove the use of stacks.
• BAA could work with the airlines using its airports to ensure the maximum
possible number of passengers/atm. This would also meet Government policy
of maximising the existing runway capacity in the UK.
11.5 Investors and shareholders are increasingly looking for green credentials when
investing and it is now seen as good business sense to develop corporate
responsibility models to encompass the global warming agenda. In many cases,
organizations are able to include work planned under cost-cutting or efficiency
schemes because these activities seek to reduce the cost of energy to the business
and hence also reduce the carbon footprint produced.
11.6 As with sustainability, elements of global warming can be tracked into many
areas of business and domestic activities. Figure 6 shows in schematic form the
possible breakdown for reporting actions to address climate change impact at
Gatwick Airport. In addition, the reporting criteria identified by the World Business
Council for Sustainable Development (WBCSD) allow a logical breakdown into three
categories for considering the climate change impact of Gatwick Airport:
• Direct - under the control of the business, e.g.:
o Seeking to become carbon neutral. Examples include membership of
the UK Emission Trading Scheme, use of combined heat & power
systems, biomass, waste-to-energy.
o Sourcing renewables
o Provision of FEGP and re-conditioned air
• Indirect – not under the direct control of the business but can be influenced to
a significant degree, e.g.:
o Establishing and purchasing through a green supply chain
o Employee travel (company travel plan, offsetting flights);
o Making aircraft movement on the ground more efficient;
o Major opinion-former in the UK industry through membership of the
Sustainable Aviation Partnership and the NATS Ltd consortium.
18
•
Indirect other – not under the direct control of the business and less open to
influence, e.g.:
o The international debate on carbon offsets/emissions trading.
o Single European Sky
o UK industry observer/adviser at ICAO
12 RECOMMENDATIONS
12.1 The Committee’s terms of reference are essentially concerned with the impact
of Gatwick Airport on the local community. While the Committee does not have a
global remit it can seek to influence the debate within the UK and the
implementation of measures within BAA and at Gatwick Airport to address its climate
change concerns. It is suggested that GATCOM’s sphere of interest could be
approached as follows, using the WBCSD criteria:
12.2 It is recommended:
(1) That the Consultative Committee welcomes the efforts made to date by BAA
and Gatwick Airport in addressing the global warming agenda;
(2) That the Consultative Committee requests BAA Corporate:
a) to consider the possibility of becoming a carbon neutral operation;
b) to provide periodic updates and feedback to the Committee on relevant
matters arising from those international forums attended by BAA (e.g.,
ICAO);
c) to provide feedback on its work with others to help ensure that UK
aviation plays its role in respecting scientifically agreed environmental
limits;
(3) That the Consultative Committee requests Gatwick Airport Limited:
a) working in partnership with its stakeholders, to develop Airport Master
Plan commitments using clearly stated benchmarks specifically aimed at
improving (i.e., reducing) the carbon footprint of the airport’s operation;
b) to report all its actions and progress to address climate change in its
Corporate Responsibility report [or other specifically identified single source];
(4) That the Consultative Committee, in forming its responses to future
consultations and other changes, considers the implications for climate
change, bearing in mind the different trade-offs, including those between
local and global effects.
Ros Howell
Technical Advisor
19
Figure 6: Schematic showing possible areas for reporting actions to address climate
change impact at Gatwick Airport
NATS
Sustainable
Aviation
(UK)
Airlines
BAA
(Corporate)
Technology:
Influence/
integration
Gatwick
Airport
Ltd
Business
Tenants
Passengers
(Individual
carbon offsets)
Marketbased
options
Airport
Operations
Air
Ground
Surface
Access
Airspace
design/
operations
e.g. CDA
Efficiencies
e.g.
starting
grid
On airport
20
Off airport
Appendix 1
INDEX of ACRONYMS
ACARE
APD
ATM
BAU
CAEP
CH4
CO2
EC
ETS
EU
EWF
FTO
GHG
GWP
H2O
IATA
ICAO
IPCC
MtC
NOx
O3
ONS
RF
RFI
UNFCC
WBCSD
Advisory Council for Aeronautics Research in Europe
Air passenger duty
Air traffic management
Business as usual
Committee on Environmental Protection (ICAO)
Methane
Carbon dioxide
European Community
Emissions Trading Scheme
European Union
Emission weighting factor
Federation of Tour Operators
Greenhouse gas
Global warming potential
Water
Internal Air Transport Association
International Civil Aviation Organisation
Inter-Governmental Panel on Climate Change
Million tonnes of carbon
Mixture of oxides of nitrogen, NO and NO2
Ozone
Office of National Statistics
Radiative forcing
Radiative forcing index
United Nations Framework Convention on Climate Change
World Business Council for Sustainable Development
21