13th October, 2021
The International Air Transport Association (IATA), which represents the world’s airlines, has announced its commitment to achieve net zero emissions by 2050. This replaces its previous, long-standing commitment to cut 2005 levels of emissions by 50% by 2050.
With an increasing number of countries adopting goals of net emissions by 2050, IATA needed to show that the aviation sector is keeping up. Their revised target comes as the UN’s aviation body ICAO prepares to adopt its own long-term climate goal for international aviation next year. While some scientists argue the goal of ‘net zero by 2050’ is not ambitious enough to ensure a safe climate, achieving it in aviation will be hugely challenging and will require some really fundamental changes.
According to IATA, if passenger numbers rise as forecast, the industry will need to abate 1,800 million tonnes of CO2 per annum by 2050. (For comparison, the industry emitted around 50% less – 914MtCO2 – in 2019.)
Alongside a small (3%) reduction arising from efficiency improvements, IATA is hoping for significant carbon cuts from alternative fuels, new propulsion technologies, and carbon removals and offsets.
Sustainable aviation fuels
IATA’s plan to abate 65% of the sector’s carbon emissions through sustainable aviation fuels (SAFs) goes beyond previous industry forecasts of what is possible and would require production to reach 449 billion litres globally by 2050. The UK industry’s Sustainable Aviation initiative estimates that around 30% is a more realistic target. The ‘SAF’ label is, meanwhile, a generalisation for a host of alternative fuels that range from biofuel to synthetic kerosene made from captured carbon and hydrogen using vast amounts of renewable power. Some of these are greener and more scalable than others.
We can’t rely on increasing amounts of waste to support a SAF strategy, for example, and some biofuels compete with food production. While the industry has been quick to rule out such feedstocks, there is a real concern that high targets will drive unsustainable production.
Finally, IATA’s estimates appear – wrongly – to conflate SAF use with emissions reduction, claiming that if 65% of the fuel used by 2050 is SAF this is equivalent to an emissions reduction of 65%. Any emissions reduction from SAFs will be on a ‘net’ rather than an ‘actual’ basis, as the CO2 released once the fuel is burned will be as high as from kerosene, requiring careful analysis of how much CO2 has been effectively captured or avoided in advance. No SAFs yet in commercial production are able to deliver a 100% emissions saving.
New propulsion technology, such as hydrogen
13% of the sector’s emissions will be abated through new propulsion technology, such as hydrogen, according to IATA. The possibility of hydrogen aircraft operating commercial routes remains speculative however. Some manufacturers hope to have regional hydrogen aircraft operating from the mid 2030s (even optimistic forecasts do not anticipate the use of hydrogen planes for long haul journeys this side of 2050) but the extent to which this technology can be successfully rolled out will depend on factors including the availability of surplus green hydrogen and installing the necessary supporting infrastructure, in addition to successful development of the aircraft themselves.
Hydrogen will not necessarily, meanwhile, eliminate the industry’s non-CO2 impacts. The Paris Agreement is based on a temperature goal, so the sector should be addressing all of its climate impacts, not just those from its CO2 emissions. The latest scientific evidence concludes that, to date, only one third of aviation’s net contribution to warming comes from its CO2 emissions, with the remaining two thirds attributed to non-CO2 impacts, such as aircraft NOx and the formation of contrail cirrus.
Carbon capture and storage and offsets
Even with optimistic levels of SAF and in-sector emissions reductions, IATA admits that around 360Mt of CO2 emissions per annum in 2050 will still need to be offset or removed from the atmosphere. In fact, only removals are likely to be relevant by this date as all sectors will need to be achieving net zero, and carbon removal technologies are still in their infancy, and will require huge and expensive infrastructure.
IATA, recognising the scale of the challenge, is calling for government support and incentives. Unless governments also impose policies and measures that internalise the climate cost of flying, though, it’s not likely that we’ll see large-scale take-up of new technologies. The sector should be paying significantly higher carbon prices, potentially hundreds of dollars per tonne of CO2 in future. The global average at the end of 2020 was just $22 per tonne.
The industry is planning on meeting huge rises in passenger numbers in the hope that appropriate technologies will be available and affordable in future. Unless and until the barriers to rolling out these technologies can be overcome, we should be planning for less flying for net zero aviation to be even a possibility.