Airplane in the runway


4 minute read

Offsetting and sustainable aviation fuel: two ways to mitigate the climate impact of air travel

As air travel is increasing after the Covid-19 pandemic, the spotlight on its role in contributing to climate change is intensifying. Options are emerging to enable flying with a clearer conscience – but what does the tick box “offset” mean when booking a flight, and are there ways to directly reduce the emissions produced by air travel?

Chris Stokel-Walker, author, speaker and journalist

Chris Stokel-Walker


“First reduce air travel where you can, second reduce emissions from the flights you still take, and then finally offset whatever emissions you cannot eliminate or reduce. That’s a model we could, and should, all follow,” says Hugo Stenberg, sustainability manager and team lead for climate and circular economy at Neste, the global leader in producing sustainable aviation fuel (SAF) and renewable diesel.

The first part of the model, reducing air travel where you can, is quite easy to grasp. But what about reducing and offsetting emissions in a hard-to-abate sector such as aviation, which currently accounts for around 2.5% of global carbon dioxide emissions? A number that is forecasted to substantially grow over the coming decades if no action is taken.

“Flying, despite all the good things that it brings and the opportunities it provides to make the world smaller and bring you to places, has a huge effect on the climate,” says Chris Oskam, head of sustainability at Sunweb Group, a leading European travel organization.

Carbon offsetting – what and how?

As a solution, many airlines and other companies now offer passengers the opportunity to purchase carbon offsets to mitigate the climate impact of flying. But how do these offsets make your flight more sustainable?

By ticking the “carbon offset” box you are financially supporting projects that help combat climate change by either preventing additional CO2 from getting into the atmosphere, or removing carbon dioxide directly from the air. One example is investing in forest preservation, which either ensures trees are maintained in a particular area or that new trees are planted to draw in carbon dioxide from the atmosphere.

Hugo Stenberg explains further: "Carbon credits represent one ton of CO2 avoided or removed from the atmosphere as a result of a project or intervention. Carbon credits are traded in a marketplace for companies and individuals to compensate for their greenhouse gas emissions occurring elsewhere.”

Certification is available by organizations such as The Gold Standard to verify the accuracy and efficiency of a carbon offsetting scheme – it is worth checking the offsets you are buying meet such industry best practices.  “It’s important to increase the transparency of the implications of offsetting,” says Stenberg and points out that while offsetting is useful, it doesn’t replace direct reductions in emissions.

“We as Neste like to say that all solutions are needed,” says Stenberg. That means not just using carbon offsets – which as Oskam points out, can never wind back the carbon impact of flying, but can only compensate for the impacts elsewhere – but finding better options that can alleviate the impact on our environment.

Reducing emissions – what and how?

One such solution to reduce air travel related emissions, available today, is sustainable aviation fuel (SAF). It’s a direct replacement for fossil jet fuel and reduces greenhouse gas (GHG) emissions by up to 80%* over the fuel’s life cycle compared to using fossil jet fuel. SAF is made from renewable raw materials, such as wastes and residues including used cooking oils.

Oskam says: ”It’s currently more economically efficient to purchase carbon offsets than to spend the equivalent amount in buying SAF, but using SAF actually curbs the carbon impact of flying – as opposed to mitigating it.”

The huge increase in Neste’s SAF production capability with the expansion of their renewables refineries in Singapore and the Netherlands, opening in 2023, will help respond to increasing demand and boost the availability of SAF as a key solution to significantly cut aviation emissions.

Both Oskam and Stenberg stress that when it comes to making travel more sustainable, there is a wide landscape of solutions to consider.

“There are different things we should and can be doing. For example, the aviation industry can improve the sustainability of flying by considering all kinds of optimization factors, such as ensuring routes and loads are as efficient as possible,” Oskam says.

With the need to limit the global temperature increase to 1.5C in mind, Stenberg says: “The end goal is clear. Making air travel more sustainable, with all the solutions available to us, has a big part to play in reaching those targets.”

So when booking your next flight, be sure to check what options are available to reduce the emissions of your flight. More and more airlines are using SAF and may even offer the option to buy SAF for your flight.

 “Ticking an offset box when booking a flight is great, but reducing your emissions with SAF is even better," concludes Stenberg.


*) When used in neat form (i.e. unblended) and calculated with established life cycle assessment (LCA) methodologies, such as CORSIA methodology

Credits: Chris Stokel-Walker, author, speaker and journalist whose work has appeared in BBC News, The New York Times and WIRED UK.