Uncertainty about political stability, as observed in the meta-level macro-environment, perpetuates in global climate change and aeropolitical negotiations. As it stands, the prospects for multilateralism prevailing, as opposed to disintegration into a fragmented climate regime or complete regime collapse, is uncertain. Despite commitments to conclude negotiations on a post-2020 climate regime under the UNFCCC by 2015 [66], or to make progress in negotiations on an MBM for aviation emissions under ICAO by 2013 [67,68,69], the future-regime architecture remains uncertain.

Should multilateralism prevail, this could lead to a multilateral agreement imposing top-down and legally-binding carbon constraints in the next two decades, or, alternatively, a bottom-up pledge-and-review type regime. However, as 2050 approaches and the impacts of climate change become more evident, the probability of a multilaterally agreed, top-down burden-sharing regime for climate change mitigation (i.e., strict limits), including for aviation emissions, becomes greater. A global price on carbon linked to the capping of allowable emissions would in all likelihood then become a reality, or, if not, at least an alternative-regime architecture that imposes carbon budgets/constraints. In the absence of a global solution, countries and regions can be expected to resort to unilateral action (which, in turn, may trigger retaliatory trade wars and aviation/tourism supply chain disruptions), or carbon constraints could be introduced through the global trade regime (such as border tax adjustments).

In addition, it is also unclear what the future for the regulatory regime for aviation will hold [11,63]. Negotiations on a global MBM for aviation emissions under the ICAO have been at an impasse for nearly 15 years, and because aviation has been treated as a special case in the UN system, international aviation emissions have for all intents and purposes been excluded from UNFCCC negotiations (see Article 2.2 of the Kyoto Protocol [70]).

Currently, the aviation industry is regulated by the Chicago Convention, which was adopted in 1944, before the era of modern commercial aviation and the globalisation of trade [71,72]. It has been argued that this regime inhibits industry growth, competition and liberalisation of the skies [73,74]. The probability of this regime being replaced by a new treaty is regarded as small, and given the transnational nature of this industry, continuation of the status quo is also unlikely [63]. Some modernisation of the Chicago regime by tying in air transport services with the world trade regime is a possibility [73].

Based on current economic and population trends, including the shifting balance of economic and political power “from North to South and West to East” [42], new patterns of global GDP growth—and with that, aviation and tourism growth—are emerging.

Tourism growth is driven inter alia by the rapid expansion of the world’s middle class, the spread of global trade, the revolution in information and communication technologies, the increasing prominence of tourism in national development plans, as well as a real decline in the cost of air travel [75,76,77].

In their 2030 tourism demand modelling, the UNWTO [78] attaches the greatest weighting to (i) GDP growth, (ii) the real cost of air travel (which is in turn linked to load factors, fuel prices and fuel-efficiency gains, and global networks that render destinations more accessible), and (iii) maturing GDP elasticity of tourism demand.

Over the past four decades, air traffic growth in turn was strongly negatively correlated with the real cost of air travel, where the latter has seen a decline of approximately 60 per cent since 1970. Over the same period, RPK growth has tracked world trade growth and GDP growth, but it has proved to be more sensitive to world trade than GDP growth [79]. Other drivers of aviation growth include growth in foreign direct investment (FDI) flows; the gradual deregulation of the skies, allowing for greater competition; the spread of airline alliance strategies and hub-and-spoke configurations, and the burgeoning middle class in the emerging markets [47,63,80]. Another significant trend fuelling air travel and competition has been the rise of new-model low-cost carriers [81].

The single biggest driver of future growth will likely be the rapid income growth in emerging economies. While the traditional tourism source markets remain flat following the 2008/9 economic downturn and the prevailing Eurozone crisis, emerging market outbound travel is growing by just under ten per cent per annum. These countries will bring some “2 billion new middle class consumers [into the potential market] by 2030” [82]. By 2030, the size of the global middle class is likely to grow to 4.9 billion, of whom between 3.2 and 3.9 billion will be located in emerging economies [62]. Coupled with “increased connectivity between major cities” [79], urbanisation in emerging markets is a strong lead indicator of future aviation and LHT growth [83]. IATA [79] highlights that 20 per cent of global air travel is currently generated by 26 mega-cities (>10 million population) and 40 percent by 62 metropoles (>5 million population).

Future public perceptions about LHT and aviation are important. LHT may be regarded as a “force for good” that leads to social inclusion and a transfer of resources from the “haves” to the “have-nots”. Because of its direct impact on GDP and job creation (in particular for young people and women) as well as other indirect and induced impacts in the broader economy, LHT is well positioned as a vehicle for social inclusion. Of the approximate 260 million total jobs sustained by travel and tourism in 2011, 100 million were direct, meaning there is a multiplier of 1.6 in employment creation potential into the broader economy [77]. In 2011, the direct, indirect and induced contribution of tourism to global GDP was some nine per cent [77].

That said, one of the future risks is that tourism as a leisure activity may be seen by local populations as an elitist activity, especially if it is not practiced in an ethically, culturally sensitive and preserving, and environmentally responsible fashion. This could introduce a future that can be described as one for the “happy few”, where locals despise tourists, and “[t]hose with money have limited time for holidays and … pay high prices for their holidays”, and those with “plenty of free time for cheap vacations at home or visiting friends and relatives” do not travel internationally and view LHT with much suspicion, thereby reinforcing “social polarisation” [8].

The starting point is to consider historical fuel-efficiency improvements in the aviation industry. Dray, Evans and Schäfer [84] underscore that “[s]ince 1970, new aircraft have become more fuel-efficient at the rate of 1%–1.5% per year on average. The typical lifetime of an aircraft in the global fleet is around 30 years, so aircraft nearing the end of their lives can use 30% or more extra fuel than corresponding new models”. If these numbers are extrapolated into the future, the fleet in 2020, of which 42 per cent are expected to be new aircraft, will on average be 25 to 30 per cent more fuel-efficient than current stock [79,85]. Considering that fuel makes up at least 30 per cent of airline operating costs, there is a strong bottom-line incentive to reduce emissions through efficiency improvements [86,87].

IATA has committed the airline industry to a peak-plateau-and-decline emissions trajectory (see Figure 6), reducing its “net carbon footprint to 50% below what it was in 2005” by 2050.

The IATA trajectory provides for two mid-term milestones, namely “to continue to improve fleet fuel efficiency by 1,5% per year until 2002” and to “cap its net carbon emissions while continuing to grow”, i.e., achieve carbon-neutral growth (CNG), from 2020 [4,47,50]. CNG means that total aviation emissions will peak and plateau at a certain level, despite the growth in air traffic volumes. CNG should not be confused with carbon-neutral aviation, which would imply zero net emissions.

The four carbon abatement pillars underpinning these targets are as follows [46,79,88,89,90].

What should be stressed is that after 2030, the mitigation potential of the first three pillars (i.e., the medium-term decarbonisation options excluding long-term step changes), will have nearly reached its full potential [46]. Beyond 2030, the aviation industry enters a period of great uncertainty in respect of ways and means to achieve climate mitigation targets. By all indications, save for radical technological breakthroughs, only the gradual replacement of kerosene jet fuel with lower-carbon second-generation biofuels is on the horizon as a radical post-2030 technological solution—but even this option is clouded by uncertainty about feedstock production, its financial viability (given the prevailing subsidisation of kerosene jet fuels), and environmental sustainability considerations, such as life-cycle emissions and the impact of land-use change on emissions [46,91,92,93]. The “sustainable aviation biofuel” mitigation wedge lends itself to incremental drop-in over the next two decades, but, realistically, given the likely long lead times to develop the supply chain (involving feedstock production, production plants and refineries, blending facilities and new global distribution systems), a meaningful contribution will materialise only after 2030 [94], which is when steep, absolute emissions reductions over a two-decade trajectory are required to meet industry’s targets. WEF [46] has estimated that, by 2050, 13.6 million barrels of low-carbon jet fuel would be required per day to meet these targets.

IATA [95] estimates that the drop-in of six per cent sustainable biofuels in the global aviation fuel mix could reduce emissions by five per cent by 2020. This will however be a modest contribution compared to what is required after 2030. ATAG’s [94] indicative share of drop-in biofuels in the total jet fuel mix is one per cent in 2015, 15 per cent in 2020, 30 per cent in 2030, and 50 per cent in 2040. However, due to the uncertainty about feedstock availability (which links to sustainability considerations, and physical land and water availability), other analysts suggest more conservative assumptions. The UKCCC [96], for example, suggests an upper limit of ten per cent drop-in by 2050.

To deliver the volumes required by 2050, a number of barriers have to be addressed. These are (i) technical viability, safety, practicality and certification; (ii) the financial case for investment; (iii) environmental sustainability; (iv) scalability of feedstock production, processing and distribution, and (v) competition from the automotive sector.

Regarding the first barrier, overwhelming evidence based on laboratory tests and test flights suggest that the drop-in of second-generation biofuels is technically sound and that “no significant aircraft engine modification is required (…) due to their comparable energy density to kerosene jet fuel” [45].

In respect of the second barrier, the status quo is characterised by “market failures due to policy uncertainty (…) and lack of adequate incentives” [46,93,97]. In addition, “[t]he energy and chemical industries have few incentives to invest in the aviation biofuels niche market if other less risky and volatile or higher-margin options exist for the use of biomass”, not least biodiesel for land transport, and renewable polymers [46]. The cost differential between conventional jet fuel and biofuels is huge, with the latter being 150 to 300 per cent more expensive than kerosene [46]. However, this is likely to change once a price incentive is in place and aviation becomes part of a global MBM for emissions trading (with a price on carbon to internalise the cost of externalities). The factors impacting the financial case will change as technology development moves through the typical maturity life stages, which run from R&D, demonstration, deployment and diffusion to full commercialisation.

With reference to the third barrier, the sustainability of drop-in biofuels relates to its life-cycle emissions; the impact of feedstock production on food security, water resources, forest cover and biodiversity; the energy and fertiliser inputs required; the yield per unit of production area, and the socio-economic benefits to local communities [91,94,97,98].

The biggest uncertainty relates to the fourth barrier, namely the scalability of second-generation biofuels up to and beyond 2030. A steady supply of feedstock (i.e., raw materials/biomass from which biofuel is derived) is an obvious precondition for scaling [93,94]. It is generally accepted that feedstock “accounts for 50 to 80 per cent of biofuel production costs” [99], and, in the case of second-generation biofuels for air transport, as much as 85 per cent [92]. While recognising that a portfolio/combination of biofuel feedstock sources would be required, ATAG [94] estimates the “land area equivalents required to produce enough fuel to completely supply the aviation industry” at a hypothetical 68,000 square kilometres for algae, or 2 million and 2.7 million square kilometres respectively for camelina or jatropha. For algae, there are both on-shore and off-shore possibilities, and thus virtually no need for competition with food production [92]. To achieve the scale required, different government departments will need to break out of their silos and co-sponsor national policy frameworks in support of the biofuels industry. Not only is it necessary to align national transport, energy, aviation and environmental policies, but, from the vantage point of delivering sufficient second-generation biomass, close alignment with agricultural, rural development and water policies is also needed [46].

Depending on the scale achievable for biofuels drop-in, the creation of a global MBM that allows for off-setting of aviation emissions against cheaper emission reductions in other economic sectors are therefore indicated. Simultaneously, an MBM that puts a price on carbon could also provide a critical price incentive for investment in the development of a second-generation biofuels industry [92,100,101]. However, due to the complex aeropolitical and climate change negotiating dynamics referred to earlier, creating such an MBM is clouded by significant political uncertainty.

By mid-century, “a business-as-usual scenario would result in (aviation and) tourism emissions exceeding the emissions budget for the entire global economy” [49]. Although aviation is responsible for only two per cent of global carbon emissions, it is emitted by an even smaller percentage of the world population who travel. On a per-capita basis, “a single long-haul journey may exceed what can be considered sustainable per capita per year emissions” for any individual [102]. The increase in the carbon footprint of aviation will also be driven by changing consumer behaviour, specifically the twin trends of travelling over longer distances and for shorter stays [83].

Global absolute emissions need to peak and start declining in absolute terms within this decade if there is to be a (50/50) chance of avoiding a temperature increase of more than 2 ºC during this century [103]—a level which will already have far-reaching consequences, but is regarded as more manageable. Should the average global temperature increase breach certain temperature increase thresholds, the Intergovernmental Panel on Climate Change (IPCC) suggests that various tipping points will be reached, causing irreversible damage to ecosystems, human livelihoods and, by implication, tourism assets [43].

Related to environmental concerns are resource constraints—more specifically, the prospects for so-called “peak oil” before mid-century as well as the threatening gap between water supply and demand [9].

The WEF’s [42] 2012 environmental scan for global risks identifies water, which is located in the “water-energy-food-climate” security nexus, as a potential resource constraint with far-reaching consequences for many economic sectors. These sectors include tourist destinations that compete with other economic sectors for water resources, for example freshwater-based tourism activities, golf tourism, agri-tourism and eco-tourism [4].

Essentially, there are four critical issues in respect of oil, namely “price, supply, availability and substitution capacity” [63]. The timing of “peak oil” (namely “the point at which half of all usable reserves are extracted”) are central to any scenario [62]. In the case of aviation, with its unique safety requirements, only second-generation drop-in biofuels offer a realistic low-carbon alternative, assuming sustainability and scalability (see discussion above). Should oil production peak before 2050, more erratic supply, energy inflation and volatile fuel prices could affect consumer demand and aviation growth, and passenger modal shifts could become the order of the day [9,31,62]. By all indications, global oil demand will increase towards 2050, but there will also be new sources of energy that will slow demand growth compared to BAU. What is not certain is whether new technologies and high oil prices “will bring vast quantities of new oil to market”, or whether the world faces an oil crunch over the next four decades that will “cripple global economic growth” [61].

Long-haul tourism is expected to grow from 982 million in 2011 [104] to 1.36 billion by 2020 [77], and to between 1.7 and 1.9 billion by 2030, assuming 3.5 per cent compound annual growth in outer years [78].

Tracking the global shift of economic power towards emerging economies, much of the new outbound tourism growth will be from Asia, with China and India leading the way, but with other emerging markets in Latin America and the continent of Africa not lagging far behind [63,81,105].

In the case of tourism, the value chain is deeply fragmented [106], linkages between sub-sectors are poorly developed, and 80 per cent of industry players are small, medium and micro-sized enterprises (SMMEs) [107]. The aviation supply chain consists of various public and private role players in the vertical supply chain that often have conflicting interests, for example the oil companies have different interests to airlines in respect of R&D for second-generation biofuels [108]. Likewise, striking a balance between public and private investment in more climate-friendly technology and infrastructure is a complicated task. The lack of agreement on burden-sharing for decarbonisation between airframe manufacturers, engine manufacturers, airport and air traffic navigation authorities and airlines, points to a massive market failure. Even though many carbon abatement options entail zero or negative net cost over the medium term, upfront capital and the distribution of investment burdens through the value chain present a major challenge.

Turning to the interconnectedness of aviation and tourism: Clearly, failure in one cluster has a massive impact on the system as a whole. For example, aviation and tourism are:

Governments are increasingly recognising the integrated nature of the aviation and tourism value chains, despite the fact that it is more often than not regulated by different government line functions, with planning often occurring in silos.

Changes in the consumer landscape (e.g., the rise of green or bounded consumerism) can be voluntary, incentivised or mandatory. Voluntary behavioural change (e.g., voluntary emissions off-setting for flights, passenger modal shifts from air transport to high-speed, mass-transit land transport, vacationing closer to home, as well as substitution of business travel with videoconferencing and other modern ICTs) is generally associated with higher awareness levels, moral persuasion, austerity measures and other industry and government-driven information-based approaches. Incentive-based behavioural change can be expected to be motivated by the pricing of carbon. Finally, command-and-control-type public policy interventions, such as the introduction of personal carbon quotas, capped airline emissions or strict limits on airport infrastructure expansion, could all reduce travel propensity.

British Airways Chief Executive Officer (CEO) Keith Williams [109] recently observed: “Now consumers live in a world where they are being educated about how their actions can affect the world’s fragile ecosystems and the global climate; we have seen a significant shift in the demand for ethical travel and green holidays.” As it stands, however, the uptake of voluntary off-setting of aviation emissions is at an introductory stage, and although it is growing, it is from low baselines [110]. The same applies to the substitution of business travel. Partly in response to the global financial crisis of 2008/9 and associated industry austerity and productivity enhancement measures as well as technological advances, the uptake of videoconferencing and other virtual meeting ICTs is on the rise [111]. However, whether this rapid growth will be sustained is uncertain. A recent study by Oxford Economics points to only limited substitutability—more specifically, that the return on investment in business travel is 1:12,5 (travel investment to revenue), and that face-to-face meetings with new and existing customers are respectively 85 per cent and 63 per cent more effective than virtual meetings [112].

On the regulatory front, there are early indications that demand-side management in respect of LHT could become a reality in the future. Kennedy, Combes and Bellamy [113], Gleaves [114] and the UK Climate Change Committee [115], among others, all observe that active government intervention may be required in the medium term to encourage substitution of business tourism with ICT as well as passenger modal shifts away from air transport, to suppress growth in airport infrastructure, and to dis-incentivise long-haul leisure travel by charging consumers for flight emissions. Looking to 2050, some analysts [8,9,10,31] even foresee scenarios in which hard carbon constraints, such as personal carbon budgets or quotas, could be introduced. However, there are also those who believe that the shift will be in an opposite direction, at least in the next few decades, and that radical increases in demand due to the emergence of unbridled “Low Cost Low Fare Model” air transport are on the cards [116]. The latter would be characterised by lower-cost air travel due to the deregulation of the airspace, as well as increased competition, higher capacities and the spread of hub-and-spoke network models.

The meaningful decoupling of aviation and LHT growth from carbon emissions exemplifies the global paradigm shift towards a green economy over the past four decades. In response to early warning signals in the 2010s that a future climate change regime will put a binding cap and an escalating price on aviation emissions, the rapidly growing aviation and tourism sectors proactively repositioned to become green lanterns of prosperity. These sectors contribute their fair share to ongoing efforts to limit the temperature increase to below 2 °C above pre-industrial levels, while growth in tourism demand and its associated developmental benefits continue to outstrip all expectations. Globalisation and rapid economic growth in what was formerly known as emerging economies are driving LHT and aviation growth. Although air travel as such is not yet carbon-neutral, the industry’s four-decade-old commitment to reducing emissions to 50% below 2005 levels by 2050 became a reality. All indications are that the world will be spared the worst impacts of climate change over the remainder of this century.

The four-decade low-carbon revolution required visionary political and industry leaders, who stood ready to take the tough policy and investment decisions needed. Very little would have moved forward had the major forces not buried the hatchet in climate change negotiations—this was the first major signpost. The second signpost was the agreement on a long-term policy signal (i.e., cap-and-trade regime) under ICAO, which also provided the critical price incentive beyond 2020 [93,97]. Only once it became clear that “perverse subsidies, such as the non-taxation of kerosene” [4], would make way for a progressive price on carbon, the different interests in the vertical aviation industry supply chain (including airframe and engine manufactures, fuel producers and distributors, airlines, airports and air transport navigation authorities) cooperated at a higher level.

The aviation industry, working proactively on its own, would not have been enough—it needed its public-sector partners to resolve outstanding operational and infrastructural inefficiencies caused by decade-old conceptions of national sovereignty [73,90], allocate sufficient land and water for biofuel feedstock production [46,94], form R&D partnerships [123,124], set global standards in ICAO [5,79,115,125,126], and establish creative new funding mechanisms for technology deployment to de-risk private-sector investment [46,92]. All of this led to the third and most significant signpost, which was when aviation carbon emissions started to decline in absolute terms after 2030, with LHT (assessed by RPKs) growing unhindered. However, this in itself would not have been enough to close the gap. Without radical new technology breakthroughs and commercialisation by 2045, this scenario would not have materialised.

Finally, the liberalisation of the airline industry and increased competition in the skies, stable oil prices and a delay in peak oil, sustainable economic growth in Africa and the former emerging economies, linked to urbanisation and the growth of mega-cities, as well as the continued globalisation of trade, were all indispensible for the exponential growth in LHT demand and airlift. Ultimately, multilateralism and global political stability had to prevail, and globalisation had to stay on track, with emerging economies providing the necessary new impetus to the global economy. A multi-decade economic depression or de-globalisation mega-trend, which slowed down global trade and depressed household disposable income, would have been major “spoilers” in the successful unwrapping of this story.

Due to the decoupling of LHT growth from emissions growth, destinations were able to continue reaping significant social and economic benefits, but in an environmentally responsible way. This is what the new generation of green travel consumers expect. Most destinations continue to balance domestic, regional (i.e., land arrival) and long-haul air arrival markets, as well as leisure and business tourism, mainly to hedge against unforeseen external economic and security shocks and other potential supply chain disruptions. Some destinations continue to exploit low-volume, high-value markets, while many others focus on mass-based tourism—unaffected by carbon constraints. That said, there is disproportionate growth in “proximity tourism” (domestic and regional), though not to the same extent as in the “fallen angel’ scenario [8].

Due to a collective and ambitious global climate change effort, including all countries and economic sectors, global emissions peaked and started to decline early enough to avoid a temperature increase of more than 2° C. Other than for the most vulnerable small-island tourist destinations and least developed countries with low adaptive capacities, dealing with the unavoidable impacts of climate change on ecosystem assets and other tourism infrastructure remains manageable.

In 2050, the tourism sector is often compared to a “fallen angel”: Due to its historical contribution to GDP and employment, it had so much potential, but today, it is shackled to the ground by carbon constraints. Air transport’s carbon footprint became the Achilles heel of LHT. Due to the aviation sector’s failure to deviate much below its 2010 “current trajectory” for decarbonisation, and in the face of the escalating price on carbon following a (delayed) global climate deal in 2025, LHT is dis-incentivised through a combination of various public policy tools. By 2040, passenger growth stalled, and by 2050, growth had moved into negative territory. The impact on global employment and GDP is negative, with the exception of a number of destinations that switched to local and regional tourism (so-called low-carbon proximity tourism) early on. Unfortunately, the global aviation industry’s response over the past four decades can only be described as “too little too late”, and LHT is paying the price.

A key turning point was when climate change negotiations collapsed in 2015, and remained deadlocked for a decade. Missing the aviation industry’s post-2020 CNG goal was then a given, as industry moved into reactive mode and ICAO negotiations on an MBM disintegrated. Role players in the value chain simply assumed that there would be no price incentive to invest in R&D for radical new technologies and biofuels that would make a difference after 2030. The next signpost was when climate negotiations picked up new political momentum by 2020. Immediately, it became clear that the aviation industry, with its long R&D lead times, was caught unprepared. When air traffic growth (as reflected by RPKs)—a lead indicator of LHT—dropped to below two per cent per annum by 2040 as the price on carbon and real travel costs escalated, the overall decline in the prospects for LHT became an established mega-trend.

Of course, things could have been different had a “wild card” exogenous to the aviation and tourism sectors, such as a technology fix for carbon sequestration or “fairy godmother”-type solar or hydrogen-fuelled planes, entered the scene, or had a multi-decade world war, epidemic, global economic downturn or de-globalisation decimated the carbon emissions of other major emitting sectors in general, and air traffic volumes in particular, thereby reducing the pressure on air transport to deal with its carbon footprint, and dramatically increasing the opportunity cost of leisure and business travel. For a few dreamers, teleportation of tourists between continents never materialised beyond science fiction movies. The timing of peak oil is a wild card in this scenario.

The nature of tourism had to change. At a macro-level, many destinations de-linked tourism from aviation, and started reducing absolute aviation emissions—not through technology-driven decarbonisation, but through demand management, i.e., by suppressing LHT/passenger growth. In the face of carbon taxes and due to the high price elasticity of demand, LHT entered its darkest decades in history. Though LHT previously represented lower volumes compared to domestic and regional land arrivals, it had disproportionately high value in terms of tourism receipts (i.e., spending). Consequently, job losses and GDP impacts were disproportionate to the loss in volume over the last few decades. Most destinations experienced negative tourism GDP and job impacts.

Some destinations, however, had the foresight to reposition early. They decreased LHT’s share in their portfolios and, by 2020, in anticipation of unavoidable carbon constraints, shifted their focus to domestic, regional and short-haul tourism [8]. They invested heavily in mass-transit systems rather than new airports and government-subsidised airlines. These early movers also refocused their market segmentation and value propositions from mass-based low-cost markets to premium markets that deliver higher-yield tourists, which also happen to be less price-sensitive. They also only target and attract “visitors who have an affinity with its environmental outlook and [low-carbon] way of life” [9]. For them, so-called “slow” (by train, boat or bicycle) and “low-carbon” tourism became a tagline that created competitive “green” advantage in marketing and destination branding [9,64]. By recognising that LHT is not an unambiguous “good”, and that there are environmental limits to LHT, these destinations proved that alternative modes of tourism and, by implication, less LHT could still provide equal well-being to their populations.

Due to the lost decade, and even though the worst impacts of climate change have been avoided, many tourist destinations still have to invest heavily in measures to adapt to unavoidable climate change, especially in low-lying coastal areas, small-island states and water-stressed regions. A temperature increase of more than 3.5 °C is not on the horizon during this century, but the dream of avoiding a temperature increase of more than 2 °C is lost. Nevertheless, tourist destinations that depend heavily on the natural environment and climate itself have started to experience demand impacts, for example because of the decline in snow-based tourism activities and the spread of vector-borne diseases to former tourist hot spots.

Like the grim reaper, aviation and LHT have been raiding the global commons without an environmental conscience ever since global climate change negotiations collapsed in the late 2010s. There is no global limit/price on carbon that internalises the cost of negative externalities, and the real cost of air travel keeps falling on the back of new economies of scale, higher load factors, technology-driven fuel-efficiency improvements and stable oil prices. Both air traffic and emissions grew nearly unabated for four decades. This was fuelled by an expanding global middle class in the former emerging economies and Africa, persistent GDP growth in the traditional developed countries, rapid urbanisation and growth in mega-cities in Asia, booming business travel associated with the ongoing globalisation of trade, and mass-based leisure tourism supported by expansive low-cost airline networks and a consumer mindset focused on hedonistic experiences. The atmosphere is on track to warm by more than 3,5 °C during this century. Climate change has already breached critical ecosystem tipping points, with devastating social and economic impacts on many tourist destinations.

When climate change negotiations stalled in the late 2010s, it was clear that the writing was on the wall for a regime that would accelerate the decarbonisation of air travel. Linked with a rebalanced global economy that showed strong growth for three of the last four decades, this created an inescapable new reality—and a daunting one at that. Had there been more visionary political and industry leaders in the 2010s and 2020s, had peak oil realised, or and had new sources of oil not been discovered off the coast of Africa as output from the Middle East increased, maybe the cost of air travel would have stopped declining in real terms earlier on. A number of other wild cards similar to those that apply to the “fallen angel” scenario could have disrupted this turn of events, but alas, the world failed to decouple development from resource depletion.

For LHT destinations, this is what Strong [127] refers to as “Armageddon”—an overlap of the impending climate, energy, water, food and population crisis. Even though LHT continued to grow unabated, with positive impacts on GDP and jobs until about 2040, destinations are today struggling to deal with physical damage costs associated with climate change, as well as related socio-economic pressures. Today, ecosystem collapse, unprecedented water scarcity, and community/inter-state conflicts over water resources in many destinations have a negative impact on tourism demand as well as comparative advantage between destinations—destroying jobs, GDP and foreign exchange earnings in its wake.

As climate tipping points are breached and impacts become irreversible, tourism assets are depleted, inter alia due to extreme weather events, water stress, sea-level rise and coastal erosion, ecosystem and biodiversity loss, and unpredictable weather patterns [49]. The nature of the tourism supply side (i.e., nature-based product offerings) and concomitant demand patterns, including tourists’ destination selection and seasonality of demand, are all in flux, and will increasingly be so over the next five decades. That said, a limited number of destinations were able to reposition proactively, diversifying their product offerings to rely less on nature-based, climate-sensitive tourism and more on shopping, the meetings, incentives, conferencing and exhibitions (MICE) industry, and other niche offerings.

Despite the collapse in multilateral climate change negotiations during the 2010s, the aviation industry made significant gains with voluntary decarbonisation. However, rather than multilaterally agreed carbon limits/pricing, a multi-decade oil price spike caused by ongoing geopolitical conflicts drove industry investment towards a low-carbon revolution. Due to significant efficiency improvements, real travel costs remained stable, and air traffic and LHT growth continued unabated, especially as emerging economies became the drivers of global trade and prosperity. Well, at least initially. By 2030, higher oil prices (which, by then, constituted 40 per cent of airline operating costs) and the financial burden of reducing its carbon footprint weighed in on the real cost of air travel and, ultimately, LHT demand. As most other economic sectors were not similarly exposed to higher oil prices, and did not face similarly constraining climate policies, aviation and LHT carried the “lantern” largely on their own, much like the good-natured Florence Nightingale. Consequently, the world is committed to a global temperature increase of more than 3.5 °C during this century. This is bound to wreak havoc with climate-sensitive tourism destinations over the remainder of the century, with early effects evident in the decades running up to 2050, including sea-level rise, species loss, the spread of vector-borne diseases and land degradation.

On balance, this scenario is internally inconsistent in three respects: Firstly, given the transnational nature of the industry, it is unlikely that aviation decarbonisation beyond the current trajectory will realise without the price incentive created through a global deal on climate change. Although many of the available carbon abatement options for the two decades after 2010 are affordable (i.e., with net negative cost) without a price on carbon, beyond 2030, the real game-changing carbon abatement opportunities will need the “push” of a progressive carbon price. In addition, without a global ETS that allows for offsetting against cheaper carbon abatement opportunities in other economic sectors, the marginal cost of aviation decarbonisation will simply be too high. Without a public policy intervention, all the root causes of the prevailing global market failure will thus remain in place. Furthermore, in the absence of a global climate deal, it will likely be an insurmountable political task to convince a sector with a relatively small, albeit growing, carbon footprint and exceptionally narrow profit margins to “go it alone” by carrying such a heavy mitigation burden—especially if the worst climate change impacts on tourist destinations during the remainder of the 21st century will not be avoided due to the unchanged behaviour of the other 98 per cent of emitters.

Secondly, in the absence of a global climate deal, this scenario is only plausible if decarbonisation in air travel is “pushed” due to a multi-decade oil price spike, which provides a price incentive for the development of low-carbon biofuels. However, such an oil price spike will also affect other energy-intensive economic sectors, in particular land transport. That would only serve to intensify the competition for biofuels with the automotive sector, which would in turn trigger an increase in the real cost of air travel and, due to the price elasticity of demand, would lead to a change in long-haul travel behaviour. Finally, the kind of geopolitical conflict that would trigger the type of long-term oil price spike implied is also likely to disrupt aviation and LHT supply chains through other mediating driving forces, thereby compounding the internal inconsistency of this scenario.