Rebuilding air transport with a zero-carbon future in the post-Covid green recovery

Rebuilding air transport with a zero-carbon future in the post-Covid green recovery | Chris Lyle

Mon 29 June 2020 – Covid-19 has hit air transport particularly hard. As aviation focuses on rebuilding in a ‘new normal’ framework of health and safety, traveller apprehension and regulatory structure – at a time of severe economic constraints and volatility – the issue of the sector’s contribution to climate change is at risk of being sidelined. But concerns regarding that contribution are growing in the light of the Paris Agreement targets and increasing recognition of the threat of climate change. At the same time, new fuel sources are evolving in the form of synthetics and electric powerplants that have the potential to reduce air transport’s flight operational emissions close to zero by 2050. The key challenges are financing the high costs involved and setting appropriate policies to encourage investment and uptake. Chris Lyle (right) suggests a refocus on the emissions mitigation framework to be built into the air transport recovery process.


Technology and operational measures continue to improve aircraft fuel efficiency and thereby reduce carbon emissions. But even on a per unit basis, absent any increase at all in traffic (beyond that of 2019), they are substantially inadequate to respond to the climate imperative if aviation is to make its contribution to the 2°C and 1.5°C targets. Thus the air transport industry and governments are relying heavily on market-based measures (MBMs) and sustainable aviation fuels (SAF).


The primary MBM is ICAO’s globally-applicable CORSIA which has to reflect a basic commonality among 193 countries. The scheme is founded on often questionable carbon offsetting practices and is not aimed at reduction of emissions but rather at achieving a goal of carbon-neutral growth, in itself a severely inadequate ambition. The only other multinational MBM is the EU’s Emissions Trading System which has a more reliable effect but remains severely constrained in its geographic application to air transport.


Turning to SAF, these are non-fossil-oil based fuels with widely different feedstocks, although they are often taken to mean biofuels. For the most part, biofuels do not reduce sufficiently even the CO2 emitted from an aircraft in flight (excluding the emissions from the fuel production and distribution). A new generation of feedstock uses waste with much greater CO2 reduction – about 70% even on a full life-cycle basis – but faces land use, distribution, scale-up and ultimately scarcity challenges. However, a feedstock now gaining interest is CO2 itself. E-fuels are synthetic fuels made directly from CO2 captured from the atmosphere through a power-to-liquid (PtL) process (see here, for example). They have the potential to reduce air transport carbon emissions close to zero, depending on the renewable energy power source.


All types of PtL take up much less land than any type of biofuel and could be manufactured at the point of delivery. Land use is mainly required for generating renewable power. Wind power can be fully mixed with agriculture and solar power placed on built-up land. A PtL demo plant in Norway is planning renewable aviation fuel production in 2023. Significant introduction of e-fuels into service could be as early as from 2025, with mass production starting by 2030. Such fuels can be used in the current aircraft fleet without modification to engines or airframes, currently certified to up to 50% of fuel but, with small technical changes, 100% should become available within a decade.


A remaining technical challenge is direct air capture of CO2 but for an intermediate term then CO2 from industry can be used. The main roadblocks are political will, lack of pressure from the aviation and tourism communities, unsubstantiated faith in offsetting and in battery-powered aircraft, and a reluctance to pay for the additional fuel costs, which are acknowledged to be substantial. But by 2050, all aviation fuel could technically be replaced by e-fuels. The share of scarce renewable energy sources allocated to aviation could be a limitation, although to some extent countered by short-haul aircraft with electric engines powered by fuel cells and fuelled with non-carbon fuel.



Building back air transport


An article in Nature Climate Change in May concluded that 10% of the decline in global CO2 emissions attributable to the Covid-19 pandemic was the result of the reduction in air transport operations. Given the same article indicated air transport generally contributes some 2.8% of global CO2 emissions, this is a stark illustration of just how much aviation has suffered in relation to other industries, as well as of its relatively high carbon intensity. In addition, it gives an idea of just how long the industry will take to recover, with global traffic levels not expected to reach those of 2019 for several years.


Also in May, there was a paper in the Oxford Review of Economic Policy entitled ‘Will Covid-19 Fiscal Recovery Packages Accelerate or Retard Progress on Climate Change?’ by contributors including such economist luminaries as Nicholas Stern and Joseph Stiglitz. This focused on a survey of 231 finance ministry officials, central bank officials and other economists representing 53 countries, including all G20 nations, on the relative performance of 25 major fiscal recovery archetypes across four dimensions: speed of implementation, economic multiplier, climate impact potential, and overall desirability. The review of target group respondents showed the worst recovery-type policy of all 25 options, by some margin, was airline bailouts.


This may to some extent reflect rich country domestic perspectives – nationally, there may well be higher priorities and constraining international aviation means a reduction in imports of trade in services, particularly in the case of major tourist originating markets. But there are positive economic and social effects of responsible tourism in developing countries in particular – it can be one of the most effective means of transferring wealth from rich people to poorer ones. Travel and tourism represents directly and indirectly about 10% of world GDP and employment, with much higher proportional levels in many developing countries in particular. 


Unfortunately, much tourism is not so responsible, with a low retained revenue yield in the destination country and negative impacts on local communities and facilities. The tourism industry has been devastated by the Covid-19 pandemic and a rethink of the tourism model is occurring in a number of destination markets (here, for example). One aim is to restore balance between ‘overtourism’ and local quality of life, including reflection of the local environmental and ecosystem sustainability promoted through welcoming international tourists.


Air transport and tourism have traditionally functioned in separate silos, often with traffic growth and market share as driving motivators, when combined economic and social prosperity should be the goal. There is an overwhelming need for revamping the structure towards quality and, notably, to accommodate overarching global GHG emissions imperatives as well as economic recovery.



Planning for zero-carbon


The mitigation focus should be on zero-carbon rather than net-zero carbon, which would rely to an undefined but likely great extent on nebulous and heterogeneous carbon offsets, which would simply be either cheap and ineffective in reducing fossil fuel use, or very expensive without a true zero-emissions outcome. Money would be far better spent on synthetic fuel evolution than on carbon offsets.


Synthetic fuels and electric powerplants with fuel cells and hydrogen for air transport are a more than promising solution to the aviation emissions issue, as illustrated in a new EU Clean Sky report, but they need to be integral to policy planning. The reality is that if we procrastinate now, an increasing alternative – and perhaps the only one in the long-term – will be to reduce flying.


Aviation bailouts during Covid-19 have been made as a matter of urgency, with few being conditioned. Some payouts have been subject to consumer protection provisions but only a very few to climate targets, even if then on the basis of cash now for commitment in a different time scale, such as carbon net-zero by 2050. However, it is fairly clear that governments will be playing a stronger financial regulatory role in aviation than in recent years, with some perhaps returning to airline shareholding.


In the short term, the key focus is restoring the liquidity of airlines and subsequently dealing with equity and debt. The Oxford Review article suggested that bailouts for airlines should be green conditioned, for example requiring achievement of net-zero emissions by 2050 but with intermediate targets set at 5- or 10-year intervals; if airlines were unable to meet these targets, bailout funding would be converted to equity at today’s very low stock market spot prices.


Beyond providing bailouts to their airlines – an issue which is almost certain to raise international accusations of subsidy in years to come – a few governments, nearly all in Europe, are taking more general initiatives to reduce aviation emissions. These include France investing in zero-emission hydrogen-based technology and the UK creating a Jet Zero Council to help development towards a net-zero target by 2050 (see article). Several governments have taken action towards diverting passenger traffic from short-haul flights to surface transport.


The ultimate tool for governments in this context would be to cap airline operations comprehensively or by route, in line with defined benefit criteria including emissions reduction targets. Given the changing factors in tourism markets along with new virtual meetings technology, which may well reduce business travel – the dominant airline passenger revenue source –  and drive up economy fares, air transport may in any event not return to previous levels of traffic and growth.


One action which would both enable and promote government efforts would be to include international aviation into national carbon budgets, and at some point into the UNFCCC’s Nationally-Determined Contributions. This would give individual States direct accountability and associated freedom to act, putting aviation mitigation activities in the context of varying national circumstances (see author’s extended article here).


The fossil fuel tax exemption for international air transport is a hurdle against switching to SAF. The exemptions should be removed and taxes aligned with those for other sectors, but they might well be hypothecated to e-fuel research funding and financing, both public and private. The exemption withdrawal could be done in the form of an environmental charge to avoid legal constraints – the UK’s APD has taken such a sidestepping route, even if the revenues go into the general treasury. If fuel prices do not stay low, the charge could be phased in over a period of a few years. Airlines should also be subject to progressive and legally-binding synthetic fuel blending mandates, perhaps with credits for exceeding them; the scheme could be designed in such a way as to accommodate targets and benefits for airports.


Travellers should be given responsibility, accountability and choice regarding their GHG emissions. Air travel should be subject to climate labelling and, as elaborated in a previous Commentary article, an emissions levy might be applied by a country on nationals of that country and/or those others whose primary residence for tax purposes is in that country. The levy would again be hypothecated to synfuel research and financing. And the passenger would be credited for use of more sustainable flights.


Synfuel producers should be given financial incentives, with priority allocation to the air transport sector. Creation of a revenue stream from fossil fuel levies and generation of credits may be one route. Investment credits for airframe and engine manufacturers, including new entrants in field of electric powerplants, could be agreed nationally or regionally against projected target standards – which would probably mean exclusion of battery power – with penalties for non-achievement along the lines of the California Zero Emission Vehicle standard.



Cohesive policy required


The challenge is formidable, given the current devastated state of the industry, the very low cost of fossil fuel at present and estimates of synthetic fuel at several times that. But in contrast to any of the market-based measures and most biofuels, synthetic fuels and hydrogen with fuel cells and electric powerplants can solve the aviation emissions problem once and for all. That should be feasible without serious damage to the travel economy.


Ideally there should be an integrated emissions mitigation policy at the national or preferably transnational or regional level. The framework would be established whereby increasingly stringent demand management criteria would apply the lesser the effectiveness of other measures. And the time is ripe for moving beyond the CO2 focus and taking account, at least on a precautionary basis, of the cumulative GHG and contrail-induced cirrus impact of air transport, which are known to raise aviation’s proportional global warming impact significantly, if not by how much.


Such a policy roadmap should look beyond the aviation silo to travel and tourism, trade and the economy at large. The tourism industry is cognisant of the issue and is elementally concerned. Several initiatives have already been taken, including a ‘Climate Friendly Travel’ programme and a symposium of some leading scientists and engineers recently on ‘Decarbonising Aviation’.


The latter initiative is now moving towards firming up the most viable technical and economic policy options and to widespread promotion and dissemination, with emphasis on the engagement of passengers. The exercise has the participation of Responsible Tourism and the backing of World Travel Market, which will highlight developments at WTM’s global event in November this year. Ultimately there is a gateway open for consideration at the UNFCCC’s COP26 in November 2021.



Chris Lyle, the author, wishes to acknowledge the contribution of Professor Paul Peeters of Breda University of Applied Sciences to this article. Chris is Chief Executive of Canadian-based Air Transport Economics, a Fellow of the Royal Aeronautical Society and a veteran of British Airways, the UN Economic Commission for Africa, ICAO and the UN World Tourism Organization. He has been actively involved in aviation emissions mitigation policy since before the adoption of the 1997 Kyoto Protocol. He can be reached at



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