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Aviation is crucial to our goal of making the travel industry more sustainable. We are working together in our efforts to:

  • Drive consistency in emissions estimates for flights across our coalition of brands (and in time, the wider industry)
  • Create industry-wide awareness and alignment around decarbonisation
  • Empower anyone booking travel to make more sustainable choices

The challenge

Aviation, reportedly responsible for 2.9% of global CO2 emissions, is one of the most challenging sectors in which to reduce emissions. In addition, other harmful effects of flying, such as condensation trails, or contrails, are thought to account for around half of aviation’s contribution to global warming.

Reducing emissions is a significant challenge for a number of reasons, including the long life cycles of aircraft fleets, slow-to-adapt policy environments, and the high cost and low supply of Sustainable Aviation Fuel (SAF). And unlike road transport, where there has been significant advancements in technology, much of the industry’s net zero targets rely on technology – such as direct air carbon capture, electric and hydrogen aircraft – that is still in the development stage.

We need to act now. Without rapid systematic change, there is a serious risk that decarbonisation targets will be missed; aviation, and tourism as a whole, could become unviable industries.

The solution

It’s complicated. Achieving decarbonisation in the aviation sector requires everything from increased investment and government/corporate policy change, to rapid technological innovation and action from the people booking travel themselves; whether that’s someone booking a holiday or a travel management company booking business travel.

That final piece of the puzzle – the travel booker – has huge, untapped potential.

People power

There is strong evidence to suggest that people want to travel more sustainably but don’t know how to. According to research by 76% of travellers say they want to travel more sustainably over the coming 12 months but 44% don’t know where to find more sustainable options. Recent research by Expedia Group also found that 7 in 10 people feel overwhelmed by starting the process of being a more sustainable traveller. The Travalyst coalition works to address this by presenting clear, consistent and credible information to drive change at scale.

And it’s not just the individual traveller that wants to travel more sustainably. We also know that businesses want to make their corporate travel programmes more sustainable. In recent years, businesses have been under increasing pressure from investors to report on environmental, social and governance (ESG) metrics, as well as from consumers who are increasingly aware of the climate crisis.

Transport, including flying, is an important consideration for people booking travel. Another report by highlighted that 40% of respondents actively look for sustainability information when booking transportation for their trips, while over half (51%) deemed lower-to-no CO2 emissions through their transportation choice a key part of what constitutes sustainable travel.

Indeed, before now efforts to calculate and collate emissions information have been staggered and confused, making it hard for people booking travel to make informed decisions.

Working together

Our coalition has aligned on a single, shared way to estimate lifecycle emissions for flights; the Travel Impact Model (TIM) is a transparent and continuously improving model based on the latest science. It aims to provide a single source of reliable information for calculating and presenting the climate impact of individual flight trips. The TIM has been developed by Google, in collaboration with the Travalyst coalition, and validated by Travalyst’s Independent Advisory Group. The TIM Advisory Committee (AC) has been established in order to govern its evolution and provide future validation (more on this below).

The TIM takes a variety of attributes into account, for example, aircraft type, cabin class and seat configuration. The model also incorporates upstream emissions which are emissions produced during production, delivery, and use of fuels – including upstream emissions will be beneficial as sustainable aviation fuels become more common in aviation. Additionally, the model factors in Kyoto gases, and whilst Kyoto gases do not include all non-CO2 emissions, incorporating them sets a precedent of including other climate impacts. More information on the TIM can be found here.

Thanks to the Travel Impact Model, which has been scaled through Travalyst, anyone booking travel is now able to see consistent flight emissions estimates across a number of platforms including Amadeus,,, Google Flights, Skyscanner, Travelport and (the corporate travel arm of Group). This is just the beginning – all of Travalyst’s relevant partners are in the process of adopting the TIM – and Travalyst will build on this momentum to drive adoption across the rest of the industry.

Please get in touch for more information on how to adopt the Travel Impact Model, which is free and publicly available to all.

What users see

Here are some examples of what people booking travel see when they search for a flight on some of our partner platforms.

Google Flights


At this stage the model and output used is the same across platforms, but how the individual partner chooses to display the results (whether by a flag, numbers only, or other) is determined by that partner.

The TIM Advisory Committee

As more platforms adopt the Travel Impact Model, it is critical that the model is continually developed and free for all to use. As such, the TIM Advisory Committee (AC) has been established in order to govern its evolution and provide future validation. Members of the committee represent academic institutions, NGOs and the aviation sector, and together have a deep understanding of the highly technical and science-driven factors required to develop a robust emissions reporting model. As a member of the AC, Travalyst has a vital role in guiding its development.

In the longer term

Providing consistency on flight emissions estimates, and scaling this industry wide, is a crucial first step, but there is much more we need to do. In the longer term, decarbonisation of the industry will need increased investment, policy change and significant technological innovation – all of which we’re seeking to accelerate through collaboration.