Note: This article has been updated with the latest information from IATA's review of aviation net-zero roadmaps, released 17 April 2024

We all love to travel, to explore the world, to see friends and family, and to fulfill business opportunities. But, peoples’ desire and need to fly comes with a great impact on climate change. Although new, more environmentally friendly aircraft technologies are in development, these options are unlikely to be ready for commercial use on a large scale until after 2050. Thus, aviation is facing a challenging journey to sustainability.

Aviation’s impact on climate change

Whilst aviation only accounted for 2.5% of total human-made emissions pre-Covid, for those who did fly, it represented a large part of their climate footprint. It’s important to note that only 1% of the world’s population cause 50% of global aviation emissions. Post-Covid, people will once again resume unrestricted travel, and both the volume and share of aviation’s climate impact are expected to increase significantly. In fact, international aviation emissions are expected to double — and possibly almost triple — between 2015–2050.

Radiative forcing doubles aviation’s impact

Whilst CO2 is generally viewed as the most problematic greenhouse gas, it is accepted that non-CO2 emissions from aviation (e.g. nitrogen oxide, ozone, soot and water vapour) also have an impact on radiative forcing and, consequently, the climate particularly at the higher altitudes, although it remains difficult to quantify the effect. Radiative forcing is the balance between the sun’s radiation reaching the earth, and heat leaving the earth. Current recommendations from a 2021 study are for a ‘Radiative Forcing Index’ factor of 1.9. This effectively doubles the size of aviation’s impact on climate change.

The challenges for sustainability in aviation

International aviation exempt from country pledges

International aviation was exempted from the Paris Agreement (along with shipping), largely because it cannot be easily captured by individual countries’ pledges. Instead it falls under the mandate of the International Civil Aviation Organisation (ICAO). Despite international aviation emissions accounting for approximately two-thirds of global aviation emissions, there is little motivation for individual countries to reduce those emissions (since they are not counted into individual nations’ emission accounts).

In October 2021, the International Air Transport Association (IATA) approved a collective target for the global air transport industry to achieve net-zero carbon emissions by 2050.

April 17 2024, IATA released an updated review of aviation net-zero roadmaps.

Sustainable Aviation Fuel not a quick fix

The adoption of Sustainable Aviation Fuels (SAF) is constrained by high costs compared to fossil-based jet fuels (it is two to seven times more expensive). Current aircraft can use up to 50% SAF, but SAF makes up less than 0.1% of global jet fuel supply.

Although demand is clearly increasing, a massive scale-up of SAF would require significant policy, technological, and supply-chain support, to make it sustainable, affordable, reliable and available.

There are many concerns that a SAF strategy overstates the environmental benefits (particularly as much of it would have to be shipped) and understates the risk that they could trigger food insecurity and human rights violations if customary land users are squeezed out to make way for fuel crops.

All roadmaps reviewed by IATA in their April 2024 report assume that Sustainable Aviation Fuels (SAF) will be responsible for the greatest amount of CO2 reductions by 2050. The role of SAF varies from 24%-70% (with a median value of 53%). This wide range reflects the uncertainties regarding potential supportive government action, the level of investments, cost of production, and profit potential, as well as access to feedstocks.

There has been a recent rise in countries releasing SAF targets in 2024 with the UK and Singapore leading the way:

• The UK government has confirmed new targets to ensure 10% of all jet fuel in flights taking off from the UK comes from sustainable sources by 2030 through its Sustainable aviation fuel mandate. CarbonClick favours the UK governments move to hold big emitters accountable and forcing them to take action by accelerating scaling up the production of SAF. However 10% is an ambitious target with the current volumes and production rates of SAF and Singapore's 2030 target is much more achievable.
• Singapore plans to require all flights departing the country to use sustainable aviation fuel (SAF) from 2026. They aim for a 1% SAF target from 2026 and plans to raise it to 3-5% by 2030, subject to global developments and the wider availability and adoption of SAF.

New propulsion technologies will take decades to be in use

Currently, fuel provides far more energy than batteries. The battery weight to achieve the same energy as fuel would be 47 times heavier or nearly seven times the weight of a fully fueled plane. In short, replacing fuel with a battery isn’t currently possible for larger aircraft. Decarbonising larger aircraft requires us to wait for significant improvements to batteries, or different kinds of innovation such as hydrogen. These innovations are not expected to be in wide-scale commercial use until well after 2050.

Efficiency improvements don’t have enough impact

Advanced communication systems, navigation, surveillance, and improved air traffic management tactics, such as landings using continuous descent, can all decrease unnecessary flight time, helping to reduce climate impacts. Other operational efficiencies include fuel conservation strategies such as single engine taxiing, minimising aircraft auxiliary power unit use, and holding aircraft at the gate during extended delays. While these are important steps to take, some require increased international cooperation and overall will only make a 3% difference by 2050.

The 2024 IATA review states technology and operational efficiency improvements are expected to have a similar role to SAF in the net-zero transition across the roadmaps, together contributing to about 30% of the emissions reduction in 2050 in all scenarios. The estimated emissions savings by hydrogen and battery-powered aircraft vary greatly across the roadmaps, depending on whether a strong pro-hydrogen policy is adopted, and on whether there is a rapid decline in renewable energy prices, enabling swifter uptake of electricity-based technologies.

Carbon capture — a dream of the future

Carbon capture is a new and exciting technology that removes carbon directly from the atmosphere and at most operational facilities is stored underground to prevent its release into the atmosphere. A few carbon capture facilities have looked to repurpose the carbon into products that can be used in various applications, the most exciting is for the production of SAF.

Carbon capture comes with its downsides as it requires a lot of energy to operate, and if renewable energy isn't used, you can end up putting more carbon back into the atmosphere than you take out. The process uses a lot of water - about 25 tons for every ton of carbon dioxide stored, which makes it less cost effective. Current carbon capture facilities operate at a small scale so the technology still needs to demonstrate its effectiveness at scale.

Bridging the gap to take action now

Evidently, most carbon reducing innovations are long-term solutions, but the climate emergency requires us to take action now.

While governments must implement policy frameworks that focus on production incentives for sustainable aviation fuels (SAF) like what the UK and Singapore governments have mandated, and the industry needs to support aircraft and engine manufacturers to accelerate research on clean propulsion technologies, high-quality, meaningful and transparent carbon offsetting is the right method to bridge this gap now.

Carbon offsetting

A carbon offset is a reduction in emissions of carbon dioxide or other greenhouse gases made in order to compensate for emissions made elsewhere. This is done by purchasing carbon credits from projects that grow and protect forests or build clean energy alternatives.

According to IATA, the estimated reliance on carbon offsetting to reduce emissions will be substantial for decades to come. To achieve net-zero CO2 emissions in 2050, almost all the global roadmaps suggest that the aviation sector will need help from market-based measures and carbon removals to address the residual emissions in 2050. Even if carbon removal technologies are considered an ”out-of-sector” mitigation measure, it is still both urgent and critical to develop these technologies as CO2 will be needed as feedstock for producing power-to-liquid (PtL) fuels.

The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), aims to address any annual increase in total CO2 emissions from international civil aviation above 2019 levels. The scheme ensures any increase in CO2 emissions from aviation will be offset with activities that absorb CO2, such as investments in tree planting. Airlines that increase emissions from the previous year will need to buy “emission units” that can be bought and sold directly through a carbon market. Pre-covid, the scheme was expected to cover just 21.6% of the sector’s emissions between 2021 and 2035.

With only 1% of the world’s population causing 50% of global aviation emissions, aviation has a unique opportunity to change the behaviour of just a small group of people, to make a big impact in addressing climate change.

Not all carbon offsetting is the same

Although we evidently need carbon offsetting in the short to medium term, the effectiveness and credibility of carbon offsetting are often scrutinised. Currently, the voluntary offset market is under-regulated leaving us with a huge disparity in both the value of a credit and the climate impact it has. The voluntary carbon market is rife with low-quality carbon projects. Individuals and businesses are using these projects to offset their emissions which actually are not delivering on promised climate benefits, or that have serious negative consequences for biodiversity and human rights.

Some of the key issues are:

• promising that emission reductions will materialise in future (for example, planting a tree that take 50 years to grow to maturity)
• establishing projects that require landowners to forcefully evict people living on the project area territory.
• artificially inflating baseline emissions in order to generate more carbon credits for the project
• releasing carbon back into the atmosphere once the project ends (for example, forest fires or illegal logging)
• or that the project does not contribute to achieving additional climate benefits (e.g. issuing credits on protected forests that were never in danger).

What does good carbon offsetting look like?

Done well, using quality carbon credits, offsetting is a powerful way to remove carbon and build a clean energy infrastructure to avoid further emissions.

At CarbonClick, we have combined leading industry carbon offsetting methodologies to develop our own framework (7-Point Impact Check), ensuring our projects are of the highest standard. We are dedicated to ensuring our credits stand up to the highest level of scrutiny. Before we bring on a new project, we conduct extensive due diligence to ensure our offsets meet the following criteria:

• Additionality - We back projects that would not have happened without carbon finance.
• Accuracy (over-crediting) - We review that the project’s emission removal or avoidance is accurately measured.
• Permanence - The project must store or remove carbon for a long period of time.
• Perverse incentives - We check that selling the carbon credits issued by the project doesn’t create a perverse incentive to worsen the climate crisis.
• Double counting - All carbon credits from our projects are only issued and counted once.
• Positive community impact - The project must have additional co-benefits to improve social, economic and environmental outcomes in the local area, aligning with at least three of the United Nations Sustainable Development Goals (SDGs).
• Monitoring and evaluation - Every project must have robust monitoring and verification policies to ensure it continues to meet our requirements.

The key to increasing uptake in voluntary carbon offsetting in aviation

A major hurdle for carbon offsetting in air travel is that, while 46% of people are saying that they are happy to pay a premium for carbon neutral flights, only 1% are doing so.

There are 3 key reasons for the low uptake:

1. Very few flight carbon offsetting solutions are integrated in the booking flow, meaning customers only get the opportunity to offset post-purchase
2. Consumers don’t understand or don’t relate with the projects the offset contribution go to
3. People doubt their contributions go where the airline says they go, due to a historic lack of trust and transparency

To tackle these hurdles and achieve a higher uptake, offsetting needs to be simple, meaningful and trustworthy.

• Simple — by being integrated in the booking flow so the offsetting happens at the point of purchase.
• Meaningful — contributions go to projects that truly resonate with customers. Meaningful projects should have a long-term impact, be verified by third-party registries and undergo rigorous, continued auditing.
• Transparent — providing full transparency in where contributions have gone. Unlike other providers, CarbonClick purchases carbon credits in advance, meaning the customer will receive an immediate receipt that allows them to 100% track and trace their contribution.

Carbon offsetting: Climate action to be taken now

While long-term solutions for carbon reductions are being developed, aviation leaders need to implement high-quality, transparent carbon offsetting programmes to take action right now. We only get one shot at fighting climate change. We have to do everything we can do together and we have to encourage others’ efforts in taking action.

High quality carbon offsets are here now and should be used as short to medium term solution until the limitations of SAF and new technologies are removed.

The recent work from the Integrity Council for the Voluntary Carbon Market (ICVCM) giving the green light to all major registries, 98% of the Voluntary Carbon Market (VCM), to be eligible for Consumer Credit Protection accreditation is a massive step towards creating a high level of trust and transparency in the VCM.

About CarbonClick

CarbonClick is a global leader in providing high-quality and transparent programmes for voluntary carbon offsetting in aviation. Our solutions are trusted by businesses around the world, such as Etihad Airways, Air Tahiti Nui and Changi Airport

While focussing on providing simple, meaningful and trustworthy carbon offsetting, we are also leading the way in providing next generation solutions that include:

• incorporating voluntary carbon offsetting into passenger booking systems, and loyalty and reward schemes.
• corporate carbon offsetting.
• and carbon offsetting for cargo aviation.

Would you like to learn more?

If you have questions around voluntary carbon offsetting in aviation, please connect with Dave Rouse via: https://calendly.com/dave-carbonclick/meeting

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