Making aviation pay for greenhouse gas removals
18th November, 2025
That aviation will have considerable residual emissions under a Net Zero future in 2050 has been acknowledged for a while. Estimates vary, but the volume required by 2050 is somewhere between 17 million and 21 million tonnes a year for UK aviation. A number of pathways have tried to map out the balance of contributions from the various proposed solutions to aviation decarbonisation (SAF, zero-emissions technology, efficiency gains etc), but while the trajectory for alternative fuels are taking shape due to the UK SAF mandate, and carbon pricing follows developments in the UK Emissions Trading Scheme, we still don’t have any clear idea about the role of greenhouse gas removals (GGRs).
GGRs are essentially a range of technologies and natural processes that remove CO₂ from the atmosphere and store it away. GGRs can be things like afforestation of previously un-forested areas, saltmarsh restoration (image below), biochar production, biomass burning with sequestration to produce power (BECCS), or capturing CO₂ directly from the atmosphere (Direct Air Capture or DAC).
Some solutions, often called “engineered removals” are industrial technologies that store carbon in geological formations and are therefore viewed as more permanent removals; this is as opposed to “nature-based solutions” such as forestry, where the removal can be reversed in the case of drought, wildfire or disease. True removals are distinct from offsets, because they take a tonne of CO₂ out of the atmosphere and store it away, rather than merely avoiding the release of an emission or relying on someone somewhere else to reduce their emissions.
The Climate Change Committee made it clear in their CB7 advice earlier this year that if we accept that aviation will still be using fossil fuels in 2050, then this industry will be responsible for playing a significant role for buying, and thus scaling, the economy-wide deployment of these GGR technologies.
So far so good, in theory. The problem is that there is currently no way to ensure that this happens, especially since many removal technologies are expensive and unproven at scale. Some aviation industry actors have made a number of purchases of removals credits on the voluntary carbon markets, but these have been tiny in number and insufficient to drive the rolling out of new businesses, technologies and innovations needed.
And this should come as no surprise. Climate change impacts are a market failure because emissions are an un-priced negative externality; removals can be viewed as a waste disposal service (getting rid of all that unwanted CO₂ in the atmosphere).
Climate change impacts are a market failure.”
But why would any business voluntarily choose to spend valuable resources on cleaning up that waste unless they are forced to – especially if a removal credit might cost £200 per tonne of CO₂ removed, compared to a forestry offset credit on the voluntary carbon markets which can cost as little as £2 per tonne offset or avoided.
What’s been missing at the heart of government policy is a way to link the polluter with the removal – in other words, the realisation of the polluter pays principle.
The UK government recently published proposals to include GGRs in the UK Emissions Trading Scheme (which aviation is a part of), but this will not happen before 2029 and is unlikely to drive huge increases in deployment. But in the newly published Whitehead review on greenhouse gas removals, an independent review of how the technologies can assist the UK in meeting our Net Zero targets, we see for the first time an attempt to sketch out the kind of instrument that could be used to forge that link to force the aviation industry to pay for its negative externalities.
Net Zero aviation mandate
What Whitehead proposes is the creation of a Net Zero aviation mandate. The principle being that aviation should be required to reduce its emissions on a sliding scale as we reach 2050, and in order to do that, it should be given access to a wider portfolio of solutions to help it achieve that aim than currently available under the SAF mandate. The precise mechanics of how this might be done have yet to be worked out, but one idea would be to change the project boundaries of the life cycle emissions assessment of alternative fuels to allow an international GGR removal credit (for example from a DAC plant in another country) to be used to reduce the carbon intensity of fuel supplied under the SAF mandate in the UK. International accounting rules currently mean that international credits can’t be accepted under the UK’s nationally determined contribution under the Paris Agreement. The Whitehead proposal is the first to clearly raise these accounting questions, and consider if, and how, inclusion in a reformed SAF mandate might be done.
Until now, we’ve spoken in broad terms about the need for GGRs to be the “net” in Net Zero. The CCC separation of GGRs into a separate negative emission category in carbon budgets has shown us what level of removals we might need, but has not helped us to figure out how to draw together what’s been known as “in-sector” and “out-of-sector” emissions reductions under one aviation specific pathway. We’ve spoken about hard to decarbonise industries, but we have had no way of linking negative emissions with sectors which are not making fast enough progress in reducing their own in-sector emissions.
While aviation continues to claim that the costs of decarbonisation are prohibitive, we now have the beginnings of an idea about how to make them pay those costs. This is increasingly urgent as emissions from the sector are rising faster than many have predicted.