By Paul Callister and Robert McLachlan
After a pause during Covid, aviation is once more on a growth path. There have been significant orders of new planes by many airlines and in Aotearoa there are plans to expand many airports. Christchurch airport continues to progress its plans to build a new large international airport at Tarras in Central Otago.
Despite much talk of future emission reduction strategies, the industry is still powered almost entirely by fossil fuels. The use of Sustainable Aviation Fuels (SAF) remains mainly for demonstration flights and no electric planes are yet carrying commercial passengers. Supplies of SAF remain insignificant compared with overall fuel use and rapidly expanding production of these fuels is a difficult challenge.
With the growth of flying, unless action is taken it seems inevitable that emissions will increase both globally and locally in the short to medium term. This is at a time when almost other sectors are working hard to reduce emissions.
The recently released advice from the Climate Change Commission relies heavily on new technology to reduce emissions from aviation. It argues that
within the second emissions budget period, the biggest opportunity for reducing emissions within aviation is likely to come from sustainably produced drop-in biofuels as a component of aviation fuels.
There are real challenges in producing sustainable biofuels, particularly if a goal is to not compete with food production. In an analysis of the use of crops for biofuel, primarily through the production of ethanol, Hannah Ritchie suggests that under some growth projections, the world would need around 300 million hectares of cropland to feed the planes. That is an area the size of India. Yes, sustainable aviation fuels will be an important part of decarbonising aviation. But other strategies are needed too.
In a new report with Kirsty Wild and Alistair Woodward from the University of Auckland, we identify seven key strategies that would help drive down our aviation emissions. These are 1) improved pricing, 2) carbon budgets for aviation; 3) improved emissions intensity; 4) limiting and targeting public investment; 5) public communications; 6) pausing airport expansion; and 7) investment in low-carbon domestic transport infrastructure. Our analysis is based on the Avoid-Shift-Improve framework of transportation planning and on the parallel contributions of passenger numbers, flight distance, and emissions intensity to overall emissions from the sector.
As we conclude,
No professor, chief executive, airline sustainability champion, or climate activist is under any
illusion about the challenges involved in regulating a source of pollution. But the ICAO
declaration, the ongoing Paris Agreement process, and the worsening climate crisis all point to
a rapidly closing window of opportunity for genuine action on aviation. Aotearoa, as a stand-out
beneficiary of aviation, has more to gain from timely and orderly action, and may also, through
its State Action Plan and other diplomatic efforts, foster more coordinated global action.
Planetary Ecology 