Scott Gillespie is founder and CEO of business travel consultancy tClara
“What does good look like?” On my first day as a management consultant 35 years ago, my manager explained that every problem we’d face would demand an answer to this question.
If you ask our industry what good travel looks like, you’ll get many answers. Common themes will emerge around cost, traveller satisfaction, duty of care, and policy compliance. Lately, many will include a nod to carbon emissions and travelling with a purpose.
Sincere and thoughtful answers, yes, but there is no clear, standard, and objective element here. Without a North Star metric, how do we manage measurably toward good travel today and even better travel tomorrow?
The metrics that matter
Firstly, ask which travel dimensions will senior management insist on being reported. The answer will be cost and carbon emissions. Nothing else passes the need-to-know test.
Then, ask what 'good' looks like for cost and carbon. Today, the widely-held answer for both is “low” because senior management presumably wants low travel costs on the P&L and low carbon emissions on the sustainability report.
But traditional travel policies are counter-productive. The problem is that travel managers are told to apply low-cost, low-carbon travel policies, believing that low trip costs will result in lower total travel costs and less carbon emissions. Unfortunately, striving for low-cost trips will most likely fail to achieve senior management’s expectations because low-priced trips make it easier to approve more low-value trips.
This puts more, not less, pressure on travel budgets, resulting in budget creep and extra and often unnecessary travel costs. Making matters worse, carbon emissions grow, not shrink, as more low-cost trips are taken.
The carbon intensity metric
The solution shifts our focus to a unified metric: carbon intensity, defined as the ratio of carbon emissions per unit of cost – for example, 0.75 CO2e kg per euro. This metric is already endorsed by the Science Based Targets initiative (SBTi) and the Corporate Sustainability Reporting Directive (CSRD), the latter of which may require carbon intensity reporting for business travel’s scope 3.6 emissions in addition to actual carbon emissions.
Based on IATA forecasts and my own analysis, companies may need to reduce their scope 3.6 emission intensity by 11 per cent per year for the next 25 years to reach an adequate net zero goal by 2050. Achieving this ambitious target requires controlling the intensity ratio’s numerator and denominator. The choices for travel’s intensity denominator include turnover, employees, passengers, and spend. Companies must choose carefully.
What does a 'good' carbon intensity metric look like?
In the spirit of asking what 'good' looks like, I offer these criteria for choosing the best metric for managing travel’s carbon intensity:
• Agency, as in a company’s ability to achieve the carbon intensity goal;
• Alignment to financial, management, and sustainability reporting requirements and practices;
• Credible clarity, in terms of what 'good' looks like;
• Consequences, the predictable impacts of striving to reach the goal
Neither turnover nor the number of employees are practical denominator choices because travellers and travel managers cannot control them.
The third option – a per-passenger denominator (for example, 200 CO2e kg per passenger) – is much more interesting. (NB: Air travel accounts for around 90 per cent of business travel emissions, hence the focus on passengers rather than travellers.)
In per-passenger's favour, online booking tools are making it easy for travellers to choose low-carbon flights, and airlines are aligned with the goal of reducing their per-passenger emissions. Perhaps best of all, it has good optics – it is easy for travellers to believe that choosing a low-carbon flight is best for the climate.
On the flipside, companies have little to no ability to accelerate any large airline’s reduction in its per-passenger emissions. Even worse, a negative correlation exists between per-passenger emissions and total airline emissions. As flights have become more fuel-efficient, airfares have fallen while passenger volumes and their emissions have grown.
Yes, we want airlines to reduce their per-passenger emissions to near zero by 2050. However, no managed travel programme can rely on its airlines to achieve a nine per cent per annum reduction in its programme’s per-passenger emissions anytime soon. Companies focused solely on reducing their per-passenger emissions are making a bad choice.
Spend-based carbon intensity is the answer
A spend-based intensity metric for managing travel emissions – the fourth of our denominator options named above – is therefore the only practical option. It is the best choice for these reasons:
• Agency: Companies can shrink travel’s carbon intensity by reducing the carbon used for each flight and/or paying higher airfares. The key is managing both carbon and cost.
• Alignment: Every managed programme that has a travel budget and a carbon emissions goal has, by default, a carbon intensity target. Use this target to identify carbon-acceptable airfares for every trip. Doing so ensures that the travel and carbon budgets are always in balance.
• Credible clarity: We know what good looks like for airline carbon intensity. In 2025, my analysis of IATA's industry-wide data suggests that a good target value is 0.63 kg CO2e per euro (0.60 kg per USD), well-to-wake, before RFI. This year’s CSRD reports from many major airlines and large organisations will show us if we’re on track or not.
• Consequences: Paying higher ticket prices will reduce carbon intensity, weed out low-value trips, afford higher-quality itineraries for higher-value trips, and reduce the absolute amount of airline carbon emissions.
The North Star challenge
Companies must integrate this metric into their policies, budgets and booking tools. While no booking tool currently integrates carbon intensity metrics, this gap can be bridged.
The greater challenge lies in achieving stakeholder buy-in. Some will argue that their travel is non-discretionary or resist rejecting low-cost, high-carbon airfares. But the stakes are clear: meeting carbon reduction goals requires this shift.
By adopting spend-based carbon intensity as their North Star, companies can balance financial and environmental priorities, setting a course for more responsible and sustainable business travel. The question isn’t whether we have a guiding metric – it’s whether we’re ready to follow it.