Industrial aviation contributes to 2.5 per cent of worldwide carbon dioxide emissions. To place that into perspective, aviation emissions are just under Japan’s and above Indonesia’s annual emissions for 2022 – regardless of a majority of the world’s inhabitants by no means having stepped foot on a aircraft.
Besides in the course of the peak of the COVID-19 pandemic, demand for business flights has grown exponentially over the previous few many years. This demand is predicted to proceed to develop, with current estimates suggesting a 4.3 per cent annual increase is likely over the next 20 years.
Whereas that is good for airways within the brief time period, it additionally means extra greenhouse emissions. In response, the Worldwide Air Transport Affiliation (IATA) handed the Fly Net Zero commitment in 2021 – an purpose for internet zero carbon aviation operations by 2050.
In an try to fulfill this goal, many airways are exploring the usage of sustainable aviation fuels as a substitute for the normal petroleum-based fuels.
These alternate fuels might scale back emissions from air transport, however are they really kinder to the environment?
What are sustainable aviation fuels?
Sustainable aviation fuels are stated to be able to delivering the identical efficiency as petroleum-based fuels with a much smaller carbon footprint.
They are often constituted of a variety of products, together with corn grain, oil seeds, algae, pure oils and fat, and moist wastes, equivalent to manures and wastewater remedy sludge.
In November 2023, a business airliner flew across the Atlantic on a purely sustainable gas supply made up of tallow-rendered beef and lamb suet-and different waste fat. American firm Alt Air produces sustainable aviation fuels from tallow by adding hydrogen to remove oxygen, earlier than refining the gas.
Hydrogen itself doesn’t emit carbon dioxide when burned or utilized in a gas cell, nonetheless, if launched into the environment hydrogen increases the amount of other greenhouse gases equivalent to methane, ozone and water vapour. The small molecules that make up hydrogen are troublesome to comprise, making leakage into the environment simple and customary.
Whereas tallow-based gas, or different sustainable aviation fuels, have been proven to cut back carbon dioxide emissions throughout flight, there’s much less visibility on the broader environmental impacts on how these gas options are sourced and produced.
Feeling the demand for sustainable aviation
Relating to tallow-based gas, there’s not but sufficient data to find out the correlation between present meat provide calls for and aviation gas calls for.
If tallow had been to be scaled to grow to be a significant aviation gas supply, there’s little data on the potential impacts on the meat trade, and whether or not elevated demand may drive unsustainable practices.
Tallow shouldn’t be the one sustainable aviation gas supply, so the demand may very well be supplemented by different sources to cut back strain on the meat trade. However some studies suggest that the usage of options like corn and seed oils as an aviation gas supply can result in biodiversity loss, deforestation, further strain on water sources, and elevated demand for land and commodities.
These crops are clearly additionally vital as meals, so there’s a query round whether or not we will afford to place extra strain on agriculture, particularly at a time when excessive climate events-which have gotten extra frequent and extreme on account of local weather change-is more likely to put supply chains at risk.
The cruel realities of sustainability
Lately, the sustainability of economic air journey has improved.
Between 2005 and 2019, gas consumption per passenger-kilometre reduced by 39 per cent. Whereas there are alternate technique of bettering the effectivity of economic flight, sustainable aviation fuels stay a distinguished technique of decreasing carbon dioxide emissions for the aviation trade.
In the end, sustainable aviation fuels do provide a greener future for flights, however the diminished carbon dioxide emissions can’t be the one measure of sustainability-the broader environmental impacts of sourcing and producing these fuels should even be thought-about.
The thought of sustainability wants to increase past one metric. Diminished carbon dioxide emissions throughout flight is a optimistic factor to purpose for, however not if it ends in different domains shouldering the environmental burden of their manufacturing.