Is ecology in trail running really a binary question?

There are conversations that keep going after you've left the movie theater. This is one of them.

I recently attended the screening of a documentary about Blandine L'Hirondel, which tells the story of her journey as a top-level athlete, but also the person behind the performances. Beyond the results and competitions, the film lets you discover a personality, her relationship to trail running, and the realities that come with a professional athlete's career.

At the end of the screening, Blandine was on stage with the director and her partner, Mathieu Masbernard, for a Q&A with the audience. A question came up on a subject that's become impossible to avoid in trail running: the environment and the UTMB.

Blandine's answer interested me, but it's mainly a sentence said afterward by Mathieu that stuck with me:

"It's not binary."

And maybe that's exactly how we should start talking about ecology in sport.

Can you be an athlete and question the impact of your sport?

That's also what struck me in Blandine's answer. As a professional athlete, she understands the environmental stakes surrounding her sport. But she's also a direct participant in it. Her job is to run, compete, and take part in this international ecosystem.

So there's inevitably a form of contradiction: she can be aware of the environmental impact of certain practices while being required, as part of her professional activity, to take part in them. And that situation deserves to be looked at with nuance.

Asking a professional athlete to bear sole responsibility for the environmental footprint of the system they operate in would obviously be reductive. Decisions about the competition calendar, locations, business model or participation conditions go well beyond her alone. That doesn't mean these practices shouldn't be questioned. It simply means we need to distinguish the athlete's individual responsibility from that of the sporting ecosystem as a whole.

You can understand the environmental stakes without considering that an athlete who takes part in a competition is necessarily being inconsistent. You can also question an event's model without asking the people who make their living from it to turn away from it overnight. The debate then becomes much more interesting: how do we evolve a system that athletes, organizers, brands, regions and spectators are all part of?

Is the UTMB really the "ugly duckling"?

Whenever the environment comes up in trail running, the UTMB comes up very quickly in the conversation. That's fairly logical: the event has become international and extremely high-profile. It draws runners from all over the world and concentrates significant activity in the Mont-Blanc valleys over several days. So it's entirely legitimate to question its impact, and the numbers give reason to do so.

In its impact report, the organization states that the HOKA UTMB Mont-Blanc's 2024 carbon footprint came to 18,600 tonnes of CO2e, or around 1.6 tonnes per runner. Above all, travel accounted for 88% of that footprint, the vast majority of it linked to runners' and companions' flights.

That's probably one of the most interesting things to take away. The event's main environmental problem isn't necessarily the trail markings or the cup used at an aid station. It's mobility. Bringing thousands of people into a mountain valley from dozens of countries inherently has an environmental cost. And that raises a question that's much harder to solve than a simple "let's ban plastic bottles".

But the UTMB isn't doing nothing

This is where the debate gets interesting. The UTMB has said for several years that it's working on its environmental impact. For 2026, the organization notably strengthened its mobility policy. Runners can get a 30% boost to their odds in the race-entry lottery if they commit to following certain lower-carbon travel rules. The organization has also introduced a mandatory carbon contribution for participants and various stakeholders.

The organization also says it has invested more than €500,000 a year since 2023 in its mobility setup, with 120 buses, 15 routes and 28 stops.

That doesn't mean the UTMB has become an "ecological" event. And that's not really the point either. An event that generates a significant carbon footprint remains an event whose impact deserves to be questioned. But you have to be able to hold two ideas at once: the UTMB's impact deserves to be questioned, and the actions it has put in place also deserve to be looked at. That's exactly what a non-binary approach allows.

What if we asked the same questions of every sport?

This is where Mathieu's point interested me in particular. He was pointing out that we focus a lot of attention on the UTMB, while international sport is full of events whose format also raises questions about travel and environmental impact.

The comparison with football is interesting. The 2026 World Cup was organized across three countries, the United States, Canada and Mexico, and 16 host cities. FIFA presents this edition as the first World Cup held in three countries and the biggest in its history, with 48 teams.

FIFA also has a sustainability strategy, which includes plans to measure and reduce emissions linked to the tournament, work on travel, and limit environmental impacts.

Again, this isn't about saying "the World Cup pollutes more, so the UTMB is fine". That would be falling right back into the binary reasoning I'm trying to avoid. The better question is: why do we accept certain travel models in one sport, while immediately considering a different model absurd in another sport?

Maybe the problem isn't the event, but the model

A sporting event doesn't only have an environmental impact. It can also have economic, social and local benefits. A race can bring business to accommodation providers, restaurants, shops, service providers and volunteers. It can help put a region on the map and create local momentum.

But these benefits shouldn't become an excuse to ignore the negative externalities. Conversely, carbon footprint shouldn't be the only metric used to judge an event. That's probably the whole difficulty: how do you fit environmental impact, economic benefits, local life, the participant experience, the organization's business model and the reality of professional athletes into the same equation? There's probably no simple answer.

So what should we ask of sporting events?

Maybe not to be perfect. But to be able to measure their impact, make it transparent, and show what they're actually trying to improve. We can then discuss whether the proposed solutions make sense. Is it enough? Is it too slow? Are certain measures actually effective? Should we go further?

These questions are legitimate. But they become much more interesting when they're based on data rather than on an opposition between "responsible event" and "irresponsible event".

That's ultimately what I take away from that evening with Blandine L'Hirondel. She wasn't trying to present a perfect position. She simply acknowledged that she was part of a system whose contradictions she was also aware of. And Mathieu's sentence sums up the idea pretty well: it's not binary.

Ecology in sport probably shouldn't be a contest to name the good student and the bad one. It should be a reflection on what we're doing today, what we can change tomorrow, and the compromises we're genuinely willing to accept. Because, fundamentally, the question might not be "is the UTMB ecological?", but rather: what should a major trail running event look like in a world that needs to reduce its environmental impact?