Abstract and Figures

Emissions from aviation will continue to increase in the future, in contradiction of global climate policy objectives. Yet, airlines and airline organisations suggest that aviation will become climatically sustainable. This paper investigates this paradox by reviewing fuel-efficiency gains since the 1960s in comparison to aviation growth, and by linking these results to technology discourses, based on a two-tiered approach tracing technology-focused discourses over 20 years (1994–2013). Findings indicate that a wide range of solutions to growing emissions from aviation have been presented by industry, hyped in global media, and subsequently vanished to be replaced by new technology discourses. Redundant discourses often linger in the public domain, where they continue to be associated with industry aspirations of ‘sustainable aviation’ and ‘zero-emission flight’. The paper highlights and discusses a number of technology discourses that constitute ‘technology myths’, and the role these ‘myths’ may be playing in the enduring but flawed promise of sustainable aviation. We conclude that technology myths require policy-makers to interpret and take into account technical uncertainty, which may result in inaction that continues to delay much needed progress in climate policy for aviation.
Content may be subject to copyright.
Please refer to the published version when citing:
Peeters, P., Higham, J., Kutzner, D., Cohen, S. & Gössling, S. (2016). Are technology myths
stalling aviation climate policy? Transportation Research Part D: Transport and
Environment, 44, 30-42, DOI: 10.1016/j.trd.2016.02.004
Are technology myths stalling aviation climate policy?
Emissions from aviation will continue to increase in the future, in contradiction of
global climate policy objectives. Yet, airlines and airline organizations suggest that
aviation will become climatically sustainable. This paper investigates this paradox by
reviewing fuel-efficiency gains since the 1960s in comparison to aviation growth, and by
linking these results to technology discourses, based on a two-tiered approach tracing
technology-focused discourses over 20 years (1994-2013). Findings indicate that a wide
range of solutions to growing emissions from aviation have been presented by industry,
hyped in global media, and subsequently vanished to be replaced by new technology
discourses. Redundant discourses often linger in the public domain, where they
continue to be associated with industry aspirations of sustainable aviation and zero-
emission flight. The paper highlights and discusses a number of technology discourses
that constitute ‘technology myths’, and the role these ‘myths’ may be playing in the
enduring but flawed promise of sustainable aviation. We conclude that technology
myths require policy-makers to interpret and take into account technical uncertainty,
which may result in inaction that continues to delay much needed progress in climate
policy for aviation.
Keywords: Aviation, climate change, discourse, technology, climate policy
1. Introduction
Aviation has experienced substantial growth over the last 40 years. Aviation industry
data show there were about 3,700 aircraft in the global commercial fleet in 1970, and
9,100 by 1990 (Boeing 2014, Airbus 2014). By 2010, this number had again more than
doubled to 21,000. Even greater has been growth in revenue passenger kilometres
(RPK), which increased nearly nine-fold between 1970-2010, from 500 billion RPK in
1970 to 4,500 billion in 2010 (Airbus 2014). By 2030, industry expectations are that
there will be approximately 40,000 aircraft producing more than 10,000 billion RPK per
annum (Boeing 2013). Continued growth after 2030 is expected: air travel will almost
quadruple between 2005 and 2050, with an average worldwide growth rate of 3.5% per
year, and energy use triple, accounting for 19% of all transport energy use in 2050,
compared to 11% in 2006 (IEA 2009; see also Owens et al. 2010).
There is thus strong evidence that aviation’s global energy use and associated emissions
have consistently grown and will continue to grow. This is in sharp contrast to pledges
by industry to reduce absolute emissions from aviation through technology (e.g. IBAC
2009; IATA 2014). Formal responsibility for emission reductions, however, was
assigned to the International Civil Aviation Organization, under the 1997 Kyoto
Protocol, some 20 years after interactions between exhaust fumes and atmosphere
chemistry had first been established (Fabian 1974, 1978), and three years after
aviation’s impact on climate was first discussed in a comprehensive set of scientific
proceedings (Schumann and Wurzel 1994). Article 2(2) of the Kyoto Protocol excludes
international aviation bunker fuel emissions from the reduction commitments of Annex
I Parties. Aviation emissions are instead to be pursued through ICAO, in recognition of
the difficulty of assigning responsibility for international emissions through individual
countries (Clarke and Chagas 2009). Emissions from domestic flights are included in
national GHG inventories and are part of national emission reduction targets (Bows and
Anderson 2007).
The EU had been increasingly critical of ICAO’s role in mitigation (Clarke and Chagas
2009), and in 2005 commissioned a study to assess options to include aviation in the EU
emission trading system (ETS) (Wit et al. 2005). Emissions from all flights from, to and
within the European Economic Area (EEA) were initially to be included from 2012, with
a cap of 97% of average annual emissions from 2004-2006, declining to 95% in
subsequent years (European Parliament and Council 2009). However, due to resistance
from in particular the US, China, and Russia (Euractiv 2014), until 2016 only emissions
from flights within the EEA will fall under the EU ETS. In the meantime a global market-
based mechanism addressing international aviation emissions is to be developed by
ICAO to be implemented by 2020 (European Commission 2014).
As a consequence, while global emissions from aviation continue to increase rapidly, no
international policy will in the foreseeable future address this situation. The only
approach to emission reductions, the EU ETS, is, as outlined, not functional, as it only
includes aviation within the EEA: it is long-distance flights, however, that make up the
majority of emissions (e.g. Peeters et al. 2007; Pels et al. 2014; Wood 2011). Moreover,
the system does not consider non-CO2 emissions, implying that the contribution of
aviation to radiative forcing may actually increase through emission trading (Lee and
Sausen 2000), which will result in cost increases too small to lead to significant
behavioural change towards less flying (Jotzo 2010; Mayor and Tol 2009; Pentelow and
Scott 2010, 2011). In contrast, communication by airlines and airline organisations
proposes that emissions from aviation will continuously decline and zero emission
flight will be achieved in the future, as evident in industry ‘roadmaps” towards
climatically sustainable aviation (Figure 1; ATAG 2010).
Figure 1: Industry’s view on long-term emission reductions
Source: ATAG (2010); emission growth from Gössling and Peeters 2015; sustainable goal
assuming 80% reduction by 2050 from 2015 levels.
As Figure 1 indicates, technology, air transport management (operations),
infrastructure, as well as additional technologies and biofuels will ultimately result in
absolute emission reductions by 2050 (ATAG 2010). Notably, the strategy implies that
emissions from aviation continue to grow, and ATAG (2010) anticipates only modest
growth rates until about 2020 (lower than the peak in 2007), when economic
measures will add to the effect of technology, operations, infrastructure and additional
(yet unknown) technologies and (yet non-existing) biofuels. Underlying the graph is a
proposition that aviation will become increasingly efficient, and that in the long run,
low-carbon fuels will replace fossil fuels.
Yet, the strategy, presented in 2010, already contradicts actual emission pathways
(Figure 1, Scientific scenario curve). By contrast, the sustainable emission pathway
(Figure 1, ‘Sustainability goal’ curve) clearly illustrates that the ATAG scenario
represents a watering down of the challenge for sustainable aviation. With regard to
efficiency gains, airlines have indeed become more efficient (Peeters and Middel 2007),
i.e. there has been a decline in fuel consumption per passenger kilometre (pkm) (Figure
2). Since the 1960s, fuel consumption per pkm has declined rapidly, by some 70%
(notably, however, jet pistons have been far more efficient). In particular A380 and
B787 have made contributions to efficiency improvements, with the A380 being
somewhat less efficient than the B787. While further improvements in efficiency can be
expected, it also appears clear from Figure 2 that year-on-year savings are likely to
decline and it is questionable whether efficiency gains of 1.5% per year can be
maintained up to 2020, or even to 2050, as envisaged by industry. Indeed, Peeters and
Middel (2007) expect fuel efficiency gains to decline to <1% per year in the 2020s, a
suggestion that would also be mirrored in comparisons of year-on-year fuel efficiency
gains and observed absolute emission growth rates (Figure 3). As shown in Figure 3,
growth in emissions has since the 1960s outpaced efficiency gains, a result of pkm
volumes growing faster than efficiency gains.
Figure 2: Energy efficiency gains and absolute emission growth
Source: based on Peeters and Middel 2007; Gössling and Peeters 2015
Figure 3: Annual efficiency gains (%/year reduction of energy consumption per pkm) and
absolute emissions growth rate (%/year)
Source: based on Peeters and Middel 2007; Gössling and Peeters 2015
1940 1960 1980 2000 2020 2040 2060
Global aviation emissions (Mton/yr)
Energy Intensity EI (MJ/ask)
Year of market introduction
Long haul aircraft fuel efficiency
IPCC values Sigmoidal regression A380
Piston powered airliners Additional jet airliners A350XWB
B787 Global aviation emissions
In light of this situation, this paper focuses on the discourses surrounding aviation
technology and specifically ‘zero emission flight’, a concept proposed by Snyder (1998)
nearly two decades ago. New technologies, such as hydrogen fuel, have been sought in
an “effort to achieve carbon neutral growth on the path to a zero emission future in
aviation” (Nolte, Apffelstaedt, and Gollnick 2012, p. 514), referring to aviation without
impact on climate. As technological expectations have become increasingly hyperbolic
in late industrial modernity, it is important to note that visions surrounding future
technologies are not just important for mobilising engineers and scientists; they also
play a central role in shaping market-based measures and infrastructure policy (Borup
et al. 2006).
In this paper, such aviation technological discourses are framed as ‘technology myths’,
with a ‘myth’ defined as an idea, story or narrative believed by many people, including
decision makers, even though unfounded or false (Oxford English Dictionary, 2014).
Myths may be uncritically held for various reasons (Heehs 1994; Wessels 2013),
including in order to remain in denial of a given truth (cf. Stoll-Kleemann et al. 2001).
Myths thus serve specific purposes and have real consequences, though in contrast to
Sorel (1941), who originally discussed myths as mechanisms instigating action, this
paper focuses on the role of technology myths in stalling progress in climate policy for
aviation. As outlined by Gotesky (1952: 530), the function of a myth is to keep …going
against defeat, frustration, disappointment; and [to] preserve institutions and
institutional process.” Notably, according to Gotesky (1952), myths are accepted even
though (or because) they are beyond empirical testing given their social utility.
Conceptions of myths in transport studies were first introduced by Essebo and Baeten
(2012), who discuss notions of sustainable mobility as myths that incorporate two
contradictory beliefs, i.e. that quantitative growth in mobility can be integrated with
environmental conservation. Essebo and Baeten (2012: 555) consequently note a
contradiction between rising emissions from transport in spite of technological
innovation, concluding that “…myths create internal logics that help relieve anxiety
[and] rationalise behaviour…”. Importantly, they note that fear is an element of myths;
invoking an understanding that “straying from the staked path” (ibid: 560) has
consequences, not unlike the ‘transport taboos’ described by Gössling and Cohen
(2014). Myths, in this interpretation, represent order, while transcending the myth of
sustainable aviation would imply disorder, i.e. the threat of restrictions on air travel.
2. Method
To identify technology-based solutions to greenhouse gas emissions in aviation, a two-
tiered methodology was developed, consisting, first, of an iterative expert-based
(Delphi) process (cf. Delbecq et al. 1975), in which the authors reflected on past and
present technical ‘solutions’ suggested by aircraft manufacturers, airlines, and airline
organizations to address climate change. This brainstorming resulted in a list of 20
items: generic solutions, such as ‘biofuels’, were excluded from the list, while individual
biofuels based on for instance Jatropha, Camelina, or algae were included. This Delphi-
process appeared to be the best approach in the absence of an objective model or other
appropriate overviews on technology solutions in aviation, even though the key
literature was also considered (e.g. Bowles 2010; Bruner et al. 2010; Green 2003a; Nolte
et al. 2012). All technologies were also required to be a suggested solution within the
period 1994-2013 for mitigating aviation’s GHG emissions, i.e. beginning in the year
when the first comprehensive proceedings on aviation’s climate-related impacts were
published (Schumann and Wurzel 1994), and covering 20 years to the last full calendar
year (2013). It should be noted, however, that several of the technologies, such as
hydrogen, propfan/open rotor and laminar flow have a much longer history in relation
to, for instance, oil crises.
The 20 items identified were then each entered into Google Analytics to test their
relative importance in terms of mentions on the Internet over time. The results
indicated a relative dominance of fewer items, reducing the total to eleven items that
were organised into three categories (Table 1).
Table 1: Aviation technology categories and items derived from Google Analytics
Laminar flow
Composite aircraft
Blended wing body
Solar flight
Electric flight
Open rotor or Propfan
Alternative fuels
Animals fats
The second tier of the methodology was the selection of daily print media, from which
people derive most news (Boykoff and Boykoff 2007), to analyse public discourses.
Several trial keyword searches were conducted on selected large newspapers, including
The Daily Mail (UK), The Guardian (UK), the New York Times (US), the Washington Post
(US), and the China Daily. As these searches yielded only between one and eleven news
items, a database covering a variety of global newspaper publications was instead used.
First, two of the items (Jatropha and Propfan) were entered into two different
newspaper databases, ProQuest News & Newspapers (ProQuest.com) and Factiva
(Factiva.com) to establish the functionality of the database and comparability of the
search results. While the results appeared comparable within the timeframe under
study, Factiva was chosen as the final database due to its data export functionality.
Factiva claims to be one of the leading global providers of economic and financial
information and offers access to a wide variety of global newspaper publications, such
as The New York Times, The Washington Post, The Financial Times, and The Guardian,
going back to 1980 (Factiva 2014).
Developing their own iterative search process using Factiva, the authors conducted
keyword searches of the 11 items, including some commonly used alternative terms,
and with a focus on English news items only. Alternative search terms included the
keywords “solar aircraft/airplane”, “electric aircraft/airplane”, “novel aircraft
configurations”, “wing-tube aircraft”, “animal fats”, “laminar aircraft/wing”, and “carbon
fibre aircraft”. In addition, keyword searches were conducted based on a crossword
search with aviation-related search terms, including “aviation”, “airplane”, “aeroplane”,
“airline”, “Boeing” or “jet fuel”, to ensure the relevance of the results to the aviation
sector. Additional search parameters in Factiva were set to the source category
‘Newspapers: All’, to include keyword hits anywhere in the text, to include all authors,
companies, subjects, industries and regions, and to report duplicate publications
(publications of the same article in a different outlet) separately from the total article
count. At a minimum eight different keyword searches were conducted per technology
with at least double the amount for technologies with commonly used alternative terms.
The majority of the keyword search results were below 100 articles, however, for
searches yielding over 200 news items, downloads of full text articles were limited to
the first 200 most relevant articles. Full text articles were checked with regard to the
correctness of the interconnection between the keywords. In some cases, such as “solar
flight”, searches were repeated using operators to exclude certain keywords from the
search to ensure only ‘relevant’ articles were included in the final results. Once the
search results were finalized the total number of all articles under review was 1,532.
For technologies that are not inherently linked to aviation, such as biofuels derived from
animal fats or hydrogen, which are commonly used in many different types of related
industry sectors, additional operators were included to ‘focus’ the results on those
associated with the aviation sector. For instance, for “animal fats”, the search term
“biofuel” was included. After extensive searches and analyses two items, propfan/open
rotor and Camelina fuel, were excluded from our analysis. Propfan/open rotor was
mentioned at a rate of only 1-2 news items per year, with a number of media mentions
lacking reference to it as a new engine type. Camelina closely paralleled the Jatropha
biofuel discourse and was therefore removed from the analysis.
Upon the removal of propfan/open rotor and Camelina fuel, nine key technologies and
the associated 1,294 articles were selected for further analysis. Of the 1,294 articles,
965 articles were downloaded in PDF format for qualitative analysis and in accordance
with the cut-off at the first 200 for items with over 200 results. Finally, 20 newspaper
articles were randomly selected from among the results of each aviation technology
(including every 10th article
), which were, as outlined, sorted by relevance and based
on the number of results obtained. The resulting 180 randomly selected articles were
qualitatively reviewed for content relating to the emergence, peaking and decline of the
technologies, with the results coded thematically using NVivo 10 (QSR International,
The focus of our analysis fell upon daily print media to analyse public discourses
relating to sustainable aviation technology solutions, and how successive discourses
have evolved over time. A limitation of our work relates to the link between press
agencies and organisations, media reporting and the response of policy makers. Our
research did not extend to exploring the relationship between agency releases, media
reporting and policy action. Such relationships are too complex to address across a
broad twenty-year period of media reporting (1994-2013), and across spatial ranges
(national/global) that vary greatly in terms of press agency uptake and influence.
3. Technology for sustainable aviation
Keyword searches in Factiva ultimately yielded 9 technologies, related to the three
categories, i.e. airframe (A), engine (E) and fuel (F). Table 2 summarizes the results by
category for each technology through graphics on the number of news items over time,
notes on levels of media interest, and key industry sources supporting the technology as
a potential solution for aviation emissions. Each of the technologies in these categories
is discussed in the following sections, including both the quantitative and qualitative
content analyses of the daily print media.
Where article results were below 200, this number was adjusted to ensure random selection of 20 articles.
Table 2: Overview of technologies by category and relative interest
Category *
Supporting industry sources
Total: 54
Low interest
(Airbus, 2011; Committee on
Climate Change, 2009; FAA Office
of Environment and Energy,
2005; IATA, 2009a, 2011, 2012;
ICAO, 2014; Sustainable Aviation,
Total: 288
High interest
(Airbus, 2007; IATA, 2009a,
2011; ICAO, 2007, 2014)
Total: 113
Medium interest
(IATA, 2009a, 2011, 2012;
UNWTO & ICAO, 2007)
Total: 94
Low interest
Negative: (Airbus, 2011; ATAG,
Positive: (ICAO, 2014)
Total: 105
Medium interest
(ICAO, 2014; Snyder, 1998;
Snyder et al., 2009)
43 3
Laminar Flow
Composite Aircraft
134 4 4
Blended Wing Body
131 1 24 4 711 15
Solar flight
1 1 21 1
5 5 5
Electric flight
Category *
Supporting industry sources
Total: 441
High interest
(Airbus, 2011; ATAG, 2010,
2011a, 2011b; Boeing, 2012;
IATA, 2009a, 2009b; ICAO, 2009;
WTTC, 2009)
Total: 61
Low interest
(ICAO, 2007, 2014)
Total: 90
Low interest
(ATAG, 2011a, 2011b)
Total: 48
Low interest
(Airbus, 2011; ATAG, 2010,
2011a, 2011b; IATA, 2005, 2009a,
2012; ICAO, 2007, 2009, 2014;
WTTC, 2009)
* A=Airframe, E=engine, F=fuel
4 4
Animal fats
65 5
Algae biofuel
3.1 Airframe
Laminar flow
This technology was first mentioned in 1997 and was discussed just 54 times in the
media search, indicating low media interest despite being frequently referred to by
industry (Airbus, 2011; Committee on Climate Change, 2009; FAA Office of Environment
and Energy, 2005; IATA, 2009a, 2011, 2012; Sustainable Aviation, 2008). Laminar flow
addresses the fact that when a body moves through the air, a ‘boundary layer’ will
develop on the body’s skin where the air speeds transits from the body’s speed to zero.
Under ideal conditions this boundary layer is laminar, reducing drag forces (Abbott &
von Doenhoff 1959; Hoerner 1965). Application of laminar flow goes back to the 1950s
in sailplanes and gliders (Raspet, 1951) and has been gradually applied to commercial
airliners in different contexts (e.g., supersonic laminar flow technology) over time
(Atkin, 2008).
Despite relatively little media interest in laminar flow, a spike in interest occurred in
2008-2009. Improved aerodynamics through ‘active’ laminar flow techniques involves
“…peppering wings with thousands of tiny holes”, which suck turbulent air creating a
laminar flow, and [t]ests have found efficiency gains of 20% or more, though durability
remains an unresolved issue” (The Edmonton Journal, 12/08/2007). The critical
challenge for natural laminar flow is to design wings “…whose shape maintains laminar
flow from front to back” (The New Zealand Herald, 16/03/2011).
Media references to laminar flow tend to focus on supersonic air travel and less on
subsonic flight where emissions reduction is currently most important. An exception is
the Boeing 777X which, at the 2013 Dubai Air Show, was profiled as “…equipped with a
larger, fourth-generation composite wing and a new advanced GE engine with Laminar
Flow Nacelles” (The Khaleej Times, 15/11/2013). These combined technologies were
expected “…to cut fuel burn by around 20 per cent, making it the most economical
aircraft in the world” (ibid). Laminar flow is a technology that has been and will be
applied in current and future generation airliners, but offering marginal fuel efficiency
Composite aircraft
Composites are composed of high strength fibres bonded together in a mass of resin.
Composites offer the advantages of lighter weight structures and better ability to reach
the ideal aerodynamic form. It is not a new technology, with reference in aircraft design
handbooks in the 1970s (e.g. Corning, 1976), however it has received steadily
increasing media attention since 2007, much associated with the Boeing 787
Dreamliner. Media search on composite aircraft yielded 288 articles published in the
period 1994-2013; this technology has been received with great anticipation. The B787
was described as a “revolutionary carbon-composite aircraft” (The Independent,
24/6/2009). The Daily Telegraph described new carbon composite aircraft as “a ‘game
changer’ for the aviation industry” and “the greatest aviation advance since the
passenger airline jet age began in the early 1950s” (17/11/2011). Airlines were quick
to place orders for the “…new generation of lighter weight, composite aircraft such as
the A350 or B787” (The South China Morning, 2/12/2005).
Media reference to the potential advantages of composite aircraft has focussed
overwhelmingly on the financial performance of airlines rather than emissions
mitigation. Regarding a Jetstar fleet upgrade, The Australian (2/3/2012) referred to the
“…composite aircraft's much touted 20% boost to fuel efficiency”, but only in relation to
a projected “…10 to 15% boost to the airline's bottom line”. When Qantas received new
carbon-composite aircraft in 2011 it was announced as keeping “…airfares affordable in
coming decades by curbing the worst of fuel price spikes” due to …“cheaper cost per
kilometre” (Daily Telegraph, 17/11/2011).
Post-war metal fuselage airliners are being steadily succeeded by new generation
composite aircraft, which provide weight advantages that should be considered
evolutionary rather than revolutionary (Airbus, 2007; IATA, 2009a, 2011; ICAO, 2007).
The contribution of carbon-composite aircraft to fuel savings however is relatively
small: on average an empty weight reduction of 5% can be expected where composites
replace conventional aluminium structures (Raymer 2012). The A350 and B787 have
over 50% composites (ICAO, 2014); Raymer et al. (2011) calculate that replacing half an
aircraft’s structure with composites may save 1-4% of fuel, i.e. considerably less than
communicated in the media. Like laminar flow, composite can be viewed as a
technology that will gradually enhance fuel efficiency, but at a slow pace.
Blended wing body
The idea of blended wing body (BWB) dates back to at least the 1960s, and is a flying
wing big enough to contain the cargo holds and passenger cabin; it forms an alternative
for the current standard wing-tube aircraft configuration (Green, 2003). A study by
Boeing revealed BWB could reduce fuel consumption by 27% compared to a similar
technology-level conventional design (Liebeck, 2004). It was reported that [t]he
blended wing aircraft could carry twice as many passengers as the Boeing 747 jumbo jet
but is said to use 30 per cent less fuel than the proposed next generation of 550-1,000-
seat super jumbos (The Independent, 25/1/1997). By 2001 claims emerged that Boeing
was “…developing an 800-seat plane in which passengers will travel on two decks
inside a giant wing… If all goes well (with test flights) a BWB could be ready to carry
passengers by 2010” (Sunday Mail, Queensland, 11/2/ 2001).
This discourse was perpetuated in 2003 when it was stated that BWB provides more
lift, offering greater range and fuel economy than tube and wing designs. "We see
blended wing as the wave of the future…" (Daily News, 17/11 2003). BWB was
described as “the shape of things to come” (The Independent, 30/11/2006), noting that
in order to achieve fuel efficiency gains “planes are going to have to look very different
in the future”. The Los Angeles Daily News (30/7/2007) remained upbeat when it quoted
Bob Liebeck (BWB programme manager for Boeing Phantom Works) that "we've
successfully passed another milestone in our work to explore and validate the
structural, aerodynamic and operational efficiencies of the BWB concept", and that the
“BWB concept holds tremendous promise for the future…”.
Despite these media claims, a year previously The New Zealand Herald reported that
“Boeing once toyed with a blended wing-body… but tests with a mock-up produced such
a negative reaction that the company dropped the technology” (12/6/2006). Indeed a
decade earlier, in an article titled ‘Airbus shies away from flying giant wing’ an Airbus
spokesperson was quoted to have said the BWB “…has significant drawbacks. The
problems associated with it are huge. How would you pressurise a vessel of that size…
There is also the difficulty of controlling the aircraft… because the design is
aerodynamically unstable" (The Independent, 251/1997). It appears the BWB, though
theoretically more fuel efficient, suffers practical problems making its design look
3.2 Engine
Solar flight
This technology was referred to 94 times, with little interest in solar flights expressed in
media discourses prior to 2013, when The New York Times (2/5/2013) reported the
intentions of Solar Impulse to “…be the first sun-powered plane to fly; its chief
distinction is its ability to go through the night”. The Solar Pulse project “…received the
official patronage of the European Commission, which sees in it an example of what
industry and energy policy makers should be doing to foster energy efficiency and clean
mobility" (The Wall Street Journal, 29/5/2008). Solar Pulse made history in July 2010 as
the first manned plane to fly around the clock and through the night on the sun's energy
(The Financial Express, 15/5/2011). The goal of the Solar Pulse project was not speed,
(traveling just 43mph), but rather “…to showcase that the trip can be made at all
without the use of fuel” (Pittsburgh Post-Gazette, 4/5/2013).
In terms of energy efficiency, Solar Impulse “…has a wingspan matching that of a Boeing
747 but the weight of a midsize carincluding the special batteries used to store solar
energy” (The New York Times, 2/5/2013). It was thus claimed that Solar Pulse “…could
revolutionise air travel” (The Sunday Times, 4/11/2007), and would “…provide an
exponential boost for interest in renewable energy and clean technologies” (The Bay of
Plenty Times, 6/5/2013). Interest in solar flight is perhaps directed more towards
becoming “…a cheap alternative to space satellites” (The Observer, 29/6/2003), and
“…the long-desired ‘eternal airplane’ that seldom has to land” (The New York Times,
12/1/1999). The creators of Solar Impulse have frankly acknowledged, however, that
“…solar planes will never replace fuel-powered commercial flights” (Pittsburgh Post-
Gazette, 4/5/2013). Flying directly on solar energy, i.e. with solar cells on wings, with a
significant payload and at a significant speed, is therefore physically impossible (Noth,
Electric flight
Media research revealed growing recent interest in this technology over the last four
years (with 105 news items since 1994). Most notably The Australian (2/11/2012)
reported ‘revolutionary aircraft technologies’ make it possible that a “…zero-emission
electric aircraft could be flying by 2035”. This promise is derived from claims that
“…lithium batteries will go from 200 watt hours per kilogram energy density delivered
by today's mobile phones to 1500W and 2000W hours per kilogram in two decades”,
allowing “zero emissions from gate to gate”. An electric aircraft design could reportedly
fly almost 900 nautical miles and transport 190 passengers, capturing 79% of flight
traffic (increasing to 95% at 1400nm) by the target entry into service date of 2035
The rhetoric associated with electric flight is attention grabbing. The Australian alludes
to the “… dramatic leap into zero emissions” (2/11/2012). The Times (5/7/2012) refers
to “a revolution in our skies”, describing the technology as an “unmissable opportunity”.
Coining it the “e-flight”, The Times noted “…electricity is not only a viable but, in fact, a
beautiful way of powering airplanes. We’re at the point where personal air travel is
becoming both affordable and truly green." While it is commonly discussed in relation
to “personal air vehicles” (The Press Democrat, 28/9/2011), electric flight is “…also
intended for later use in large-scale aircraft, cutting fuel consumption and emissions by
25% compared with today's most efficient aircraft drives (The Hindu Business Line,
21/6/2011). However, there is also evidence of tempered realism in these discourses.
The Times (5/7/2012) reported “…the dirty little secret with batteries that are
appropriate for medium-to-high-performance electric vehicles is that there has been no
real measurable improvement since about 2009”.
A feasibility study into hydrogen fuelled aircraft, using fuel cells for conversion to
electricity, observed that developing electronic flight through the combination of
several major new technologies is not without significant challenges (Peeters, 2000;
Snyder et al., 2009). These include development road blocks such as the need for a
completely new fuel infrastructure at airports. Pure electric battery-fuelled flights
would furthermore require significant future improvements in the performance of the
low energy density of batteries. Lithium batteries presently have an energy density of
only 1% of kerosene (Kivits, Charles, & Ryan, 2010). The low energy density of batteries
means that purely electric flight is not practically possible.
3.3 Alternative fuels
Jatropha is a crop with the ability to grow on very poor soils and thus does not compete
much with food production (Rosillo-Calle, Thrän, Seiffert, & Teelucksingh, 2012). Media
interest in this technology was high in 2008-2009, declining steadily in subsequent
years. In 2008, Air New Zealand “had successfully test-flown a Boeing 747 using a 50-50
blend of Jatropha and aviation fuel” (The Wall Street Journal, 9/3/2009). Later that year
a quote attributed to Air New Zealand that confuses relative and absolute efficiency
gains, claimed that:
…a 50% blend of biofuels and traditional fuel would increase fuel efficiency by
1 percent. That might not sound like much, but that would save 1.4 metric tons
of fuel on a 12-hour flight. The environmental benefits are even greater, with a
reduction in carbon dioxide emissions of about 4.5 metric tons for the same
flight (The Spokesman Review, 2/6/2009).
Numerous other international airlines were reported at the time to be exploring
Jatropha biofuel solutions. The Wall Street Journal (9/3/2009) observed that fuels based
purely on plant oils “performed well in test flights by airlines and jet-engine makers … ”,
quoting Honeywell International Inc., which refined the fuel for the Air New Zealand
test flight as well as for Continental Airlines and Japan Airlines flights. “When burned,
the oils produce less soot and particulate matter than regular jet fuel (and) cultivating
and refining the oilseeds produces 50% less greenhouse-gas emissions than regular jet-
fuel production” (ibid).
Referred to 441 times in a period of just 8 years, Jatropha was a pillar of sustainable
aviation discourses, mentioned in many industry reports on climate change (Airbus,
2011; ATAG, 2010, 2011a, 2011b; Boeing, 2012; IATA, 2009a, 2009b; ICAO, 2009;
WTTC, 2009). This is despite its high associated water use (Rosillo-Calle et al., 2012)
and evidence that its lifecycle GHG emissions are higher than for kerosene from crude
oil (ICAO, 2009). Jatropha has been widely taken up in the media and is still mentioned
by industry (ICAO 2014), but seems to offer little prospect for climate change
mitigation, particularly when set in the context of high current and future growth in
Animal fats
Animal fats were referred to in 61 media articles, with a short peak in interest in 2011.
The Austin American Statesman reported (21/8/2009) that “[a] company called
Dynamic Fuels is building a $138 million factory in Louisiana that will turn animal fat
into high-grade synthetic diesel and potentially even jet fuel”, further claiming that
"[t]his is the cleanest fuel on the planet". In 2011 The Business Standard (1/7/11) stated
that KLM Royal Dutch became the first airline in the world to operate a commercial
flight, carrying 171 passengers, on bio-kerosene produced from used cooking fuel oil”. It
was claimed in the US that “[h]istorians may look back at this week, when passenger
jets in the United States first made regular flights with fuels made from algae and
French fry grease, both as the beginning of a new era in aviation” (The Origonian,
That same year IATA was reported to have estimated that “… replacing 3 percent of the
kerosene in jet fuel would reduce aviation CO2 emissions by over 10 million tons, at an
initial cost of $10 to $15 billion in production and distribution facilities” (The
International Herald Tribune, 26/10/2011). While animal fats are suggested as biofuel
feedstock wastes that do not compete with food production (Hileman et al. 2009), a
critical barrier arises from the fact that bio-kerosene produced from animal fats has far
too high a freezing point (Vera-Morales & Schäfer 2009). Therefore it is used in blends
of up to a maximum of 20% (Hileman et al. 2009). Overall, the public discourse of
animal fats was short-lived.
Hydrogen was referred to in 90 articles, peaking in 2008 and again in 2010-2011. While
dating back to 1994, in 2007 Airbus formally announced it was exploring hydrogen as
an alternative fuel, along with nuclear fusion and possibly superconductivity (The
Australian Financial Review, 26/10/2007), with a particular interest in developing fuel
cell technology, which “…transforms the energy in hydrogen and oxygen into electricity
at low temperatures without moving parts, is cleaner and more efficient than
combustion engines and the waste product is water”. Airbus believed at that time that
the technology would achieve “…the target of a 50 percent reduction in aircraft
emissions and noise in nine years' time” (ibid). In the same year Boeing “…claimed a
first with the flight of a two-seat Diamond motor glider fitted with a hydrogen-powered
fuel cell and lithium-ion batteries” (ibid).
Although Airbus vowed to “…replace kerosene with hydrogen by 2020” (The
Independent, 17/11/2011), hydrogen may suffer from public perceptions influenced by
iconic images of the fatal Hindenburg inferno 70 years ago. Indeed in 2011 The
Independent (17/11/2011) reported that …hydrogen has been ditched again by the
flight industry” and “…the promised ‘green’ fuel for powering flights of the future has
been quietly shelved in favour of biofuels and more fuel-sipping aviation... In principle,
it is possible to fly with hydrogen but now we cannot produce enough hydrogen in an
environmentally friendly manner for aviation". This discourse of media scepticism dates
to 2008 when The Toronto Star (15/8/2008) reported that “[t]he alternatives for
aviation are more limited than the options for ground transportation. Most engineers
will tell you that using hydrogen or electricity to power a passenger jet just isn't
realistic, at least not for decades”. Furthermore, Boeing stated earlier that year that it
“…didn't believe hydrogen, which contains about a quarter of the energy as kerosene-
based jet fuel, could be the primary source for large aircraft (ibid).
The idea of hydrogen as an alternative fuel has been in discussion for a long time
(Brewer 1991), and is still referred to in the media. A key barrier to the use of hydrogen
includes storage: Kerosene is easily stored in the wings, but hydrogen would occupy a
substantial part of the fuselage, reducing the payload capacity of aircraft (ibid). Another
barrier is that large investment in a new fuel distribution system at airports would be
required. Despite media interest in hydrogen that was particularly apparent in 2008,
perceptual, economic and technical barriers remain.
Media search for algae biofuel returned only 48 items, centred on optimistic reporting
in 2008 accompanied by increasing realism in 2010. In 2007 Air New Zealand and
Boeing collaborated to “…create the world's first environmentally friendly aviation fuel,
made of wild algae” (The Independent Financial Review, 18/7/2007). At that time Boeing
stated publicly “…that it believes algae is the airline fuel of the future” and that “…algae
ponds totalling 34,000 square kilometres could produce enough fuel to reduce the net
CO2 footprint for all of aviation to zero” (ibid).
Forecasts published in 2008 noted that “…by 2030, algae-based biofuels could replace
fossil-derived fuels usage to the equivalent of 12% of the world's annual jet fuel
consumption - cutting more than 160 million tonnes of CO2 yearly” (The Evening Herald,
27/10/2008). Media interest in algae biofuel was particularly apparent in the US:
Algae are fast-growing, consume CO2 and have the potential to produce more
oil per acre than other biofuels. The oils they produce can be used to make
substitutes for diesel fuel, aviation fuel and gasoline. Backers say the U.S. could
meet its entire liquid-fuel needs with algal biofuels (The Wall Street Journal,
The following year The Portland Press Herald (14/6/2011) described the US algae
biofuel industry as being “…on the cusp of economic feasibility” given increasing
“…investment in biodiesel by oil companies, airlines and the US government”.
These discourses have been accompanied by less optimistic forecasts. The National Post
(16/6/2007) suggested “[a] 10% mix of biofuels with jet fuel would be a more likely
scenario in the near future” and that “just to meet the 10% goal for the U.S. airline
industry for one year, a land mass the size of Florida would be required”. Indeed “…as
promising as the technology is, it hasn't proved that it can produce fuels in sufficient
quantities or at a low enough cost to make a dent in US liquid-fuel consumption” (The
Wall Street Journal, 22/2/2010). More recently the “…economic viability of such
biofuels of algae has been questioned”, with predictions that algae biofuels will “…only
be viable when oil hits $800 a barrel” (The Washington Post, 28/2/2012).
Despite modest media uptake, microalgae are often mentioned in industry reports as an
alternative fuel for crude oil-based kerosene (Airbus 2011; ATAG 2010; 2011a; 2011b;
IATA 2005; 2009a; 2012; ICAO 2007; 2009; WTTC 2009). Microalgae are considered to
have several advantages over other feedstocks, such as the ability to live on marginal
grounds (but in artificial or natural water-basins), efficiently convert sunlight to oil,
grow year-round and produce many high value by-products (Hu et al. 2008). But there
are also barriers: land-use (Skarka 2012) and water use, low or negative lifecycle
carbon emission reductions (Quinn & Davis 2014), cost and alternative use (Coplin
2012). The prospects of algae as a feedstock to produce biofuels consequently remain
4. Discussion and conclusion
This analysis has shown that there exists a wide range of discourses with regard to the
potential of technology to make significant contributions to climate change mitigation in
aviation. Analysis with regard to airframes, engines and fuels reveals, however, that
many of the proposed solutions emerge and are hyped in the media, only to
subsequently disappear again from public discourse. This was shown on the basis of a
media analysis, which provided evidence that all fuel solutions (hydrogen, animal fats,
Jatropha and algae) had already ‘peaked’ in terms of media attention, and, except for
algae, been abandoned as feasible solutions. Hydrogen, Jatropha and algae each saw a
spike in interest in 2008, i.e. the year after the fourth assessment report of the IPCC
(2007) had been released, drawing worldwide attention to the need to engage in
mitigation and increasing pressure on the aviation industry to act on climate change.
With regard to the remaining discourses, results suggest that blended wing body has
also been abandoned as a solution, while solar and electric flight (engine), and laminar
flow and composite aircraft (airframes) represent emerging discourses in the public
domain, despite the increasing application of laminar flow and composites, and research
on solar and electric flight, since the 1970s. Notably, the notion of commercial solar
flight is rejected by Airbus and ATAG, but considered a feasible innovation by ICAO
(Table 2).
Given these findings, this paper concludes that most of the ‘solutions’ that have been
presented over the past 20 years constitute technology myths. Specifically, it is possible
to distinguish three types of myths, i.e. i) myths that refer to abandoned technologies
once seen as promising; ii) myths that refer to emerging technology discourses, though
generally overstating the realistic potential offered by these technologies (and some of
these potentially representing dead ends as well); and iii) myths that refer to solutions
that are impossible for physical reasons; this latter type of myth exemplified by the
notion of solar flight. Results also indicate that there are always various technology
discourses co-existing, i.e. even in a situation where a discourse is abandoned, various
other ‘solutions’ remain available. This is likely to have repercussions for governance.
Policymakers are increasingly confronted with technological promises that require
them to make decisions based on interpreting technical uncertainties (Borup et al.
2006). As shown in Figure 1, industry has created a vision of climate mitigation in
aviation that incorporates various elements of non-accountability, as the solution is
built on a range of strategies; foresees continued growth in emissions for another two
decades; and will consequently contribute to mitigation only in the long-term future. As
such, the roadmap to mitigation is difficult to question, because continued emission
growth is an anticipated development, while the effectiveness of the various strategies
to contribute to absolute emission reductions cannot be presently judged and evaluated.
Multiple technologies providing partial solutions make it difficult to monitor progress.
Furthermore, this vision of sustainable aviation is embedded in notions of progress
towards sustainability goals, i.e. presenting aviation as an energetically efficient
transport mode and a marginal source of emissions in global comparison (Gössling and
Peeters 2007), which obscures continued absolute growth in greenhouse gas emissions
with relative (annual) efficiency gains. Under these prevailing conditions an
understanding of aviation as a sector soon-to-become-sustainable has been, and
continues to be, successfully perpetuated. Ultimately, this would constitute a form of
propaganda in which emotional responses to aviation, for instance framed as the
sector’s social and economic benefits, are fuelled by pseudo-rational information
myths to generate a widely held understanding of, and continuing faith in a looming
future of sustainable aviation, and, ultimately, “zero emission flight” (Snyder, 1998).
This situation has implications for climate policy, because aviation as a transnational
activity is difficult to govern politically. In this situation, politicians may embrace myths
to justify non-action beyond efficiency improvements achieved through technology. For
instance, UK Energy Secretary Ed Davey suggested that If you look at the future of flight
it is possible to imagine, with technological innovation, that we will have zero-carbon
flight in the future” (Guardian, 7/10/2014). This view may reflect a genuine belief in
technology myths, or represent a convenient way to avoid upsetting the established
‘order’ (Gössling and Cohen 2014), i.e. to initiate legislation aimed at the reducing
growth in the volume of air transport itself and replacing it with other transport modes
or alternative travel patterns (Peeters and Dubois, 2010). Such policy measures would
likely to lead to resistance from lobby groups, industry, the public, and political
opposition. Indeed this line of research might be carried forward in a comparative
analysis to identify the relationships, including lag effects, between the media and
policy-makers (and others such as lobby groups and industry). While our research did
not investigate the relationship between agency releases, media reporting and policy
action, research that is theoretically grounded in agenda setting and applied in a defined
socio-political and temporal context would provide valuable insights into the agency-
media-policy nexus. In the meantime, in this paper we conclude that aviation technology
myths must be recognised, confronted and overcome as a critical step in the pathway to
sustainable aviation climate policy.
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... This is known as a "whataboutism" argument, namely other sectors emit more GHGs (Lamb et al., 2020). The airline industry claims its efforts towards "green" aviation should be acknowledged, even though there is actually no short-or medium-term serious solution beyond "technological optimism" discourses (Lamb et al., 2020) and greenwashing strategies (Peeters et al., 2016;Baer, 2020;Gössling and Lyle, 2021) so the "need to grow remains unquestioned" (Köves and Bajmócy, 2022). However, due to public concern for climate change, public authorities are looking to be seen as acting against climate change. ...
... Yet both strategies have limited potential to reduce aviation emissions. Technological and operational improvements have been more than offset by growing air travel demand to date (Graver et al., 2020;ITF, 2021;Lee et al., 2021) and technological options for decarbonizing aviation are limited in the short-term and challenging in the longer term (Committee on Climate Change, 2019; Peeters et al., 2016;Schäfer et al., 2019). 'Shift' policies are focused mainly on super-shorthaul flights which, as demonstrated in this study, account for a very small share of CO 2 emissions from air travel. ...
Several countries have considered banning or even decided to ban or tax super short-haul flights, arguing that the availability of rail alternatives makes them unnecessary. Such policies result from the need for governments to be seen as acting to mitigate climate change and scholars favouring energy (climate) efficiency perspectives over the absolute amount of fuel burnt (greenhouse gas emissions emitted). Yet climate change is due to absolute emissions, and it is a fact that the longer a flight is, the greater the amount of fuel is burnt (emissions). Considering all departing flights from 31 European countries, our study found that flights shorter than 500 km account for 27.9% of departures but 5.9% of fuel burnt. In contrast, flights longer than 4,000 km account for 6.2% of departures but 47.0% of fuel burnt, although with significant variation across countries. We conclude that targeting shorter flights (which often exist to alleviate physical obstacles imposed by physical geography) will contribute little to reducing the impact of aviation on climate, and that policy initiatives that target longer flights are urgently needed.
... Because technology innovation alone is unlikely to reduce emissions in line with decarbonization goals (McLachlan & Callister, 2022;Peeters et al., 2016), this article focuses on consumer demand choices. Several factors influence consumer demand. ...
... For other air traveler segments, credibility and transparency will weigh into purchase intentions (Babakhani et al., 2017;Zhang et al., 2019). This has relevance in light of the aviation industry's communication of climate change and the "solutions," which has been found to be misleading and untruthful (Guix et al., 2022;Peeters et al., 2016). Factors increasing voluntary purchase intentions are related to aspects that are structural (e.g., opt-in versus opt-out; Araña & Le on, 2013), policy-related (e.g., existence of national climate policies; Choi et al., 2018), project-related (e.g., offset type; Blasch & Farsi, 2014), product-attributed (e.g., local/international; Ritchie et al., 2021), or traveler-segment related (e.g., age, flight behavior; Ritchie et al., 2021). ...
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Air transport challenges the world's net‐zero carbon ambitions. The sector has consistently grown and causes warming as a result of both CO2 and other, short‐lived emissions. Two principal solutions have been proposed to reduce the contribution of aviation to climate change: innovations of technology and the development of interventions to trigger behavioral change. Technological innovations include new propulsion technologies and the use of sustainable aviation fuels. Behavioral change includes flight avoidance, substitution with other means of transport, the choice of efficient flight options, and carbon offsetting. This article focuses on behavior; it offers an overview of factors that lead to consumers traveling by air and discusses demand distribution complexities. The importance of price for air travel decisions is assessed, and evidence of travel “wants” are contrasted with “needs,” the latter investigated in light of the COVID‐19 pandemic. The review of relevant scholarly work culminates in an action list enabling air travelers, policy makers, the aviation industry, researchers and society to meaningfully advance low‐carbon air transport trajectories. This article is categorized under: Perceptions, Behavior, and Communication of Climate Change > Behavior Change and Responses The Carbon Economy and Climate Mitigation > Policies, Instruments, Lifestyles, Behavior
... The evolution of aviation technology and the impacts on climate policy have been examined by Peeters et al, 2016. The authors stated that emissions from aviation will continue to increase in the future although airlines suggest that aviation will become climate neutral. ...
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The clean energy transition is an important and urgent issue in European islands contributing in the global effort for climate change mitigation. Island of Crete, Greece is a popular tourist destination while the most of visitors arrive and depart with aircrafts. Aim of the current study is to investigate the possibility of decarbonizing the air-transportation to and from Crete. Air-transportation has a share at 10.62% in the total carbon emissions in the island while other studies have estimated higher values. This is higher than the estimated share of carbon emissions in aviation at 2-3% of the overall carbon emissions worldwide. Various technological and non-technological approaches for decarbonizing aviation are examined including improvements in aircraft's standards, use of sustainable aviation fuels, offsetting carbon emissions and developing new policies discouraging the frequent use of air travelling. The feasibility and the impacts of these methods are mentioned indicating that de-carbonization is difficult in the short and medium term. Production of sustainable aviation fuels including bio-fuels and electro-fuels in the required quantities and in competitive prices is not foreseen soon. Developing new policies that increase the cost of air travelling and promote alternative sustainable modes in transportation will have undesired impacts in the island's tourism industry. On the contrary de-carbonization in other socioeconomic sectors in Crete comprising electricity generation, production of heat and cooling and transportation inside the island is easier than in air-transportation.
... 35 Reliance on biofuel or hydrogen, or attempts to offset aviation emissions, would face challenges of their own. 36 On the one hand, the production of biofuel is likely to require large spans of arable land, 37 thus competing with food production or otherwise hindering the large-scale deployment of bioenergy with carbon capture and storage as a negative emissions technology. 38 On the other hand, producing clean hydrogen fuel would require substantial amounts of energy, which is unlikely to be economically available. ...
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Climate change mitigation calls for the limitation and reduction of greenhouse gas (GHG) emissions across all sectors. However, limiting GHG emissions from aviation has proven to be problematic for technical reasons (e.g., lack of low-carbon alternatives) as well as legal reasons (e.g., international aviation does not readily fall within any one state's jurisdiction). Relevant initiatives have followed two streams. At the international level, the International Civil Aviation Organization (ICAO) has adopted technical standards and, more recently, a market-based mechanism to limit emissions from international civil aviation. In parallel, states have adopted their own policies and measures to regulate emissions from both domestic and international aviation, ranging from tax and technical standards to traffic management and infrastructural development. While much of the literature on climate change mitigation in the aviation sector has focused on international efforts, this article reveals the importance of understanding the tensions and complementarities of the two streams.
... While technology can theoretically reconcile aviation-demand growth and climate change mitigation, such reconciliation rests upon very ambitious and potentially unfeasible technological breakthroughs and optimistic assumptions on their ability to rapidly curb emissions (for example, full zero-carbon fuels substitution by 2050 and zero-emissions airplanes substitution by 2080 or zero life-cycle emissions). The reliance on demand reductions and technological transitions to meet mitigation goals can be reduced by deploying CO 2 removal to neutralize all residual emissions and indirect effects [34][35][36] . Yet we find that different definitions of climate neutrality yield different CO 2 removal requirements and temperature outcomes. ...
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To meet ambitious climate targets, the aviation sector needs to neutralize CO2 emissions and reduce non-CO2 climatic effects. Despite being responsible for approximately two-thirds of aviation’s impacts on the climate, most of aviation non-CO2 species are currently excluded from climate mitigation efforts. Here we identify three plausible definitions of climate-neutral aviation that include non-CO2 forcing and assess their implications considering future demand uncertainty, technological innovation and CO2 removal. We demonstrate that simply neutralizing aviation’s CO2 emissions, if nothing is done to reduce non-CO2 forcing, causes up to 0.4 °C additional warming, thus compromising the 1.5 °C target. We further show that substantial rates of CO2 removal are needed to achieve climate-neutral aviation in scenarios with little mitigation, yet cleaner-flying technologies can drastically reduce them. Our work provides policymakers with consistent definitions of climate-neutral aviation and highlights the beneficial side effects of moving to aircraft types and fuels with lower indirect climate effects. Non-CO2 effects must be addressed for climate-neutral aviation but are currently ignored in international climate policies. The authors provide a framework with different definitions of climate neutrality, then show how technological and demand-side mitigation efforts can help to achieve these targets.
Kernziel der Arbeit ist es, einen Beitrag zur Konzeptfindung und zur strukturmechanischen Optimierung von Anbindungsstrukturen für Planetengetriebe in Flugtriebwerken zu leisten. Hierzu wurde ein auf CAD-Geometrien basierender Optimierungsprozess geschaffen und auf verschiedene Problemstellungen angewendet. Die Arbeit gliedert sich in sechs Kapitel, in denen ein Verständnis für die Notwendigkeit und die Problemstellung vermittelt werden soll. Die Einleitung beschreibt Entwicklungstendenzen für Triebwerke in der zivilen Luftfahrt und die Gründe für den Einsatz von Planetengetrieben. Da die hier entwickelten Methoden die Konzeptfindung und somit die Produktentwicklung unterstützen sollen, wird skizziert, an welcher Stelle des Produktentwicklungsprozesses die Methoden am besten einzusetzen sind. Das zweite und dritte Kapitel sind der Strukturoptimierung gewidmet. Zunächst werden die Grundlagen Optimierung und wichtige Ansätze erläutert. Anschließend werden die üblichen Verfahren zur Strukturoptimierung mithilfe von finiten Elemente-Netzen vorgestellt. Folgend werden zwei Sonderfälle betrachtet, die Optimierung von flexiblen Bauteilen und von mehreren Bauteilen im Verbund. Beides stellt eine besondere Herausforderung dar und wird in den späteren Fallstudien aufgegriffen. Im dritten Kapitel wird der alternative, auf CAD-Geometrien basierende Ansatz zur Strukturoptimierung vorgestellt. Abschließend werden die Methoden anhand von akademischen Beispielen validiert. Das vierte Kapitel befasst sich mit Antwortflächenverfahren. Sie sind ein gängiges Mittel, um Optimierungsprozesse zu beschleunigen. Hierzu werden zunächst die wichtigsten Grundlagen zur nötigen Versuchsplanung erläutert und die drei gängigsten Ansätze diskutiert. Auf der Grundlage eines Vergleichs dieser Verfahren wird ein geeigneter Ansatz ausgewählt. Im fünften Kapitel werden fünf Fallstudien aufgeführt. Jede davon greift eine praxisnahe Problemstellung auf und demonstriert die Herangehensweise und die Möglichkeiten und Grenzen eines auf CAD-Geometrien basierten Ansatzes zur Strukturoptimierung. Das erste, zweite und fünfte Fallbeispiel beziehen sich auf die im zweiten Kapitel genannten Sonderfälle. Im dritten Fallbeispiel wird eine Optimierung der Systemeigenfrequenz durchgeführt, die es nötig macht, eine Brücke von der Einzelkomponente zu einem aus reduzierten Matrizen bestehenden Systemmodell zu schlagen. Im vierten Fallbeispiel werden die im vierten Kapitel beschriebenen Antwortflächenverfahren eingesetzt, um die reduzierte Matrix einer Einzelkomponente für ein Systemmodell auf der Basis der Geometrieparameter vorherzusagen. Abschließend fasst das sechste Kapitel die Ergebnisse zusammen. Die gezeigten Ansätze sind sehr gut geeignet, um flexible Strukturen zu finden. Die Systemoptimierung und Prozessbeschleunigung konnten erfolgreich durchgeführt werden und haben zu signifikanten Verbesserungen geführt. Abschließend wird das Vorgehen im Vergleich zu anderen Lösungsmöglichkeiten bewertet.
Purpose The primary driver of future aviation has recently been sustainability. The rapid development of radically new, disruptive technologies and solutions should be regularly evaluated to maintain the desired trends in sustainable aviation. The purpose of this research can be listed as follows: (i) to propose a sustainable performance index and methodology (ii) to evaluate the new technologies and solutions, and (iii) apply them to evaluate the effect of technologies and solutions under development. Design/methodology/approach This paper introduces a total sustainable performance index for evaluating the sustainability; demonstrates its applicability to future development processes; recognizes the supporting new technologies and solutions by implementing their identification, evaluation and selection processes; and defines the major trends and drivers maintaining the sustainability of the future aviation. Findings This study has resulted in a proposed new “total sustainable performance index,” and methodology of identifying key drivers that allow defining the technology and solution-driven trends, and defines the major trends and listed technologies and solutions that may have a determining role in given trends. Research limitations/implications There are dilemmas on taking into account the positive effects of aviation on the economy and society that may overwrite the costs and limited information about the foresight on new technologies and solutions. Practical implications It depends on access to required inputs. Social implications Two-way effects of solid expectations of society on the possible greening of aviation can be listed as the social implication of this research. Originality/value The proposed “total sustainability performance index” totally evaluates sustainability, including a penalty, considering the policy (regulation) and interest of future generations.
Das Umfeld von Organisationen befindet sich in stetigem Wandel. Organisationen sind gefordert, sich kontinuierlich und zielgerichtet zu verändern, um ihren gesellschaftlichen Wert zu sichern. Wandlungsfähigkeit als Konglomerat unterschiedlicher Fähigkeiten ist daher entscheidend. Dabei gilt es frühzeitig Wandlungsbedarf zu erkennen, neue Wege zu erkunden und mit Widersprüchen umzugehen. In diesem Beitrag werden die Konzepte strategische Vorausschau, Boundary Spanning und organisationale Ambidexterität in Bezug auf Wandlungsfähigkeit diskutiert. Die genannten Ansätze werden anschließend in Kombination zueinander dargestellt, sodass sie sich gegenseitig ergänzen. Ziel des Beitrags ist es, Optionen aufzuzeigen, mit denen Wandlungsfähigkeit in Organisationen proaktiv geschaffen werden kann.
Following mounting concerns about climate change induced by commercial flights, the aviation industry has reacted with narratives that emphasize the increase in fuel efficiency (fuel/passenger-km) of its operations. However, climate change is due to absolute fuel burnt. In this regard, this article compares trends in fuel efficiency with absolute fuel burnt considering passenger flights from nine European airports in 2018 versus 1996. Within this sample, this article found that fuel/seat-km over this period decreased by about 30%, while the absolute fuel burnt increased 2.5 times. An exploration of the drivers of this increase revealed that it occurred in the provision of air services on preexisting and new routes mostly longer than 1,000 km. Low-cost carriers were a significant contributor to this growth if one considers relative terms and smaller airports, but not absolute terms. These results question the ability of high-speed rail to significantly offset the impacts of aviation on climate.
This article seeks to advance our understanding of the underlying reasons that sustain high levels of academic flying, and examines how a low carbon academia with less air travel might come about. Data from thirty interviews with academics showed that expectations of internationalization, networking, and ideals of a productive academic stand amongst the strongest drivers of academic flying. These drivers come forth from underlying objectives such as pursuing excellence in research and working towards successful careers. Findings from this research suggest that institutional and cultural change are prerequisites to mainstream practical alternatives to academic flying, such as wider use of digital communication tools, grounded travelling, and low‐carbon conferences and meetings. We see a role for universities, grant‐providing authorities and other academic organisations to include environmental standards and criteria in internationalization strategies, the concept of excellence and funding evaluation processes. From our analysis of academics’ experiences during the COVID‐19 pandemic, we identify three factors that appear essential in determining whether digital communication tools can substitute physical presence; (1) desired type of interaction, (2) existing social relations among participants, and (3) number of participants. Finally, we discuss whether and to which extent voluntary guidelines, the adoption of digital tools, and other soft measures may lead to cuts in academic flying at the scale and pace required for meeting climate targets, suggesting that enforcing limits on academic air travel might be unavoidable.
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This paper pioneers the assessment of tourism's total global resource use, including its fossil fuel consumption, associated CO2 emissions, fresh water, land, and food use. As tourism is a dynamic growth system, characterized by rapidly increasing tourist numbers, understanding its past, current, and future contributions to global resource use is a central requirement for sustainable tourism assessments. The paper introduces the concept of resource use intensities (RUIs), which represent tourism's resource needs per unit of consumption (e.g. energy per guest night). Based on estimates of RUIs, a first assessment of tourism's global resource use and emissions is provided for the period 1900-2050, utilizing the Peeters Global Tourism Transport Model. Results indicate that the current (2010) global tourism system may require c.16,700 PJ of energy, 138 km3 of fresh water, 62,000 km2 of land, and 39.4 Mt of food, also causing emissions of 1.12 Gt CO2. Despite efforts to implement more sustainable forms of tourism, analysis indicates that tourism's overall resource consumption may grow by between 92% (water) and 189% (land use) in the period 2010-2050. To maintain the global tourism system consequently requires rapidly growing resource inputs, while the system is simultaneously becoming increasingly vulnerable to disruptions in resource flows.
Liquid hydrogen is shown to be the ideal fuel for civil transport aircraft, as well as for many types of military aircraft. Hydrogen Aircraft Technology discusses the potential of hydrogen for subsonic, supersonic, and hypersonic applications. Designs with sample configurations of aircraft for all three speed categories are presented, in addition to performance comparisons to equivalent designs for aircraft using conventional kerosine-type fuel and configurations for aircraft using liquid methane fuel. Other topics discussed include conceptual designs of the principal elements of fuel containment systems required for cryogenic fuels, operational elements (e.g., pumps, valves, pressure regulators, heat exchangers, lines and fittings), modifications for turbine engines to maximize the benefit of hydrogen, safety aspects compared to kerosine and methane fueled designs, equipment and facility designs for servicing hydrogen-fueled aircraft, production methods for liquid hydrogen, and the environmental advantages for using liquid hydrogen. The book also presents a plan for conducting the necessary development of technology and introducing hydrogen fuel into the worldwide civil air transport industry. Hydrogen Aircraft Technology will provide fascinating reading for anyone interested in aircraft and hydrogen fuel designs.
Conference Paper
In the e�ffort to implement the IATA four-pillar strategy for emissions reduction and in view of achieving the aviation industry's high-level goals for carbon emissions reduction, IATA launched its "Technology Roadmap for Environmentally Sustainable Aviation" (TERESA) initiative bringing together manufacturers, scientists, government agencies, infrastructure service providers and airlines. Under this initiative the German Aerospace Center (DLR) and the Aerospace System Design Laboratory (ASDL) of Georgia Tech conducted the screening, description, selection, modeling and assessment of appropriate technologies. The application of the technologies into reference aircraft on their particular mission was modeled. The results of this modeling were subsequently fed into a world fleet forecast model, which takes into account an updated calendar of future aircraft entry into service. Thus the model accounts for the eff�ects of CO2 reduction potential via technology introduction on world fleet level.
In the coming century, the impact of air travel on the environment will become an increasingly powerful influence on aircraft design. Unless the impact per passenger kilometre can be reduced substantially relative to today's levels, environmental factors will increasingly limit the expansion of air travel and the social benefit that it brings. This essay considers the three main impacts, noise, air pollution around airports and influence on climate change. Of the three, impact on climate change is taken to have the greatest long-term importance and is discussed at the greatest length. It is argued that, of the three main contributors to climate change from aircraft - CO 2 emissions, NO X emissions and the creation of persistent contrails - it is the last two which are the most promising targets. Ways of reducing the impacts of these two are discussed and it is noted that, in each case, the best environmental result is likely to entail some increase in CO 2 emissions. It follows that regulatory or economic measures to reduce impact on climate should be framed so as to do just that. Measures framed purely in terms of CO 2 emissions are likely to be counter-productive. Nevertheless, the design of aircraft to reduce fuel burn and hence CO 2 emission remains a key long-term objective; the essay considers the potential offered by new technology and new design concepts in this arena.
Since 2005, the carbon market has grown to a value of nearly $100 billion per annum. This book examines all the main legal and policy issues which are raised by emissions trading and carbon finance. It covers not only the Kyoto Flexibility Mechanisms but also the regional emission trading scheme in the EU and emerging schemes in the US, Australia, and New Zealand. The Parties to the 1992 UN Framework Convention are in the process of negotiating a successor regime to the 1997 Kyoto Protocol whose first commitment period ends in 2012. As scientists predict that the threat of dangerous climate change requires much more radical mitigation actions, the negotiations aim for a more comprehensive and wide ranging agreement which includes new players - such as the US - as well as taking account of new sources (such as aircraft emissions) and new mechanisms such as the creation of incentives for reducing emissions from deforestation and forest degradation.
Myth and history are generally considered antithetical modes of explanation. Writers of each tend to distrust the data of the other. Many historians of the modern period see their task as one of removing all trace of myth from the historical record. Many students of myth consider history to have less explanatory power than traditional narratives. Since the Greeks, logos (word as demonstrable truth) has been opposed to mythos (word as authoritative pronouncement). In more general terms myth may be defined as any set of unexamined assumptions. Some modern historians have become aware that much so-called factual history is interfused with such assumptions. What we call history is at best mythistory. Some even suggest that there can be no real distinction between the discourses of myth and history, between fact and fiction. The Agastya-Aurobindo narrative is an example of an account based on factual materials that gradually became transformed into fiction. It is accepted by some as historical truth; however when its development is studied critically, one can see that successive narrators "euphemistically" transformed its constituent propositions. The Ramjanmabhumi narrative (at the center of sectarian conflict in India) took form in much the same way. It is not possible to accept these legends as historical truth, though there is no reason why they could not be used as the basis of artistic creations. To avoid conflict by attempting to keep myth and history entirely separate may not be possible because the two interpenetrate. The most fruitful approach to the problem might be to work towards a dialectical resolution.