As the foremost sporting event in the world, the Olympic Games aim to inspire people to better themselves across the board — sustainability included. Surprisingly, the Summer and Winter Olympic Games have escaped scrutiny so far when it comes to thoroughly evaluating their carbon footprint.

About half of the world’s population is expected to tune into the Tokyo Olympics, which are just around the corner. But while all eyes are on the athletes, researchers from Switzerland looked behind the scenes and conducted a systematic evaluation of the sustainability of the Olympic Games — not just for Tokyo but also for all the summer and winter games since 1992 — based on nine indicators.

The model showed that over the course of the last 16 editions of the Summer and Winter Olympic Games, the events have become increasingly expensive and less sustainable.

“The Olympic Games put sustainability at the core of their mission, but no-one ever bothered to conduct an independent, comparative study over time to see how different Games measure up against that claim,” Martin Müller, lead author of the new study and a professor in the Department of Geography and Sustainability at the University of Lausanne, told ZME Science.

Müller and colleagues were struck by two findings:

1. The sustainability of the Games has declined over time, although sustainability has become more important as a principle in the Olympic Games.
2. The most sustainable Games are not those that shouted the loudest about sustainability: Vancouver 2010 and London 2012 made much of their sustainability agendas, but do not rank among the top 5. By contrast, Salt Lake City 2002 is leading the pack, although sustainability did not play a major role in their Games communication.

Across the Olympic Games editions, the researchers found the average sustainability performance was 48 out of 100 points, which is disappointingly average for an event that prizes excellence.

This year’s Olympic Games in Tokyo are expected to cost between $12 billion and $28 billion. Yes, with a ‘B’ — and that’s not at all atypical. The final bill for Athens in 2004 is estimated at around $11 billion while Rio 2016 struggled to stick to its budget, closing at $20 billion. The most expensive Olympic Games ever were the pharaonic Sochi Winter Games in 2014, whose tab reached a staggering $55 billion.

Each host city is motivated by the previous host’s extravagance to uphold a standard of appearance, which means building new expensive sports arenas and revamping public spaces and infrastructure.

But despite the huge expenses, the researchers had to do a lot of digging in order to properly keep tabs on the carbon footprint of the games.

“The Olympic Games are among the most expensive projects on Earth. You would think that those billions of dollars spent are well documented. Far from it. It took us a long time to find even the most basic data to populate our indicators, such as the share of public funding of each Games,” said Müller.

With such stupendous expenses, it’s no wonder that the Olympic Games have been responsible for a large carbon footprint. But what was, perhaps, most surprising was the discovery that the games have become increasingly unsustainable, rather than the other way around.

The games following Vancouver 2010 scored particularly poorly. Ironically, this year’s edition of the Summer Games in Tokyo may be one of the most sustainable in recent history due to the coronavirus pandemic, which will see far fewer tourists flock to the arenas.

“The pandemic will likely have the curious, but unintended, effect of making Tokyo more sustainable than originally planned. Lower international attendance will lead to a smaller carbon footprint. My hope is that this could prove a model for organising future Games with less cost and fewer visitors,” said Müller.

But for upcoming editions, which hopefully won’t be disrupted by a new pandemic, the researchers have proposed a number of actions in order to improve sustainability. These include a reduction in the number of in-person spectators that might reduce the venue size, setting up and enforcing new sustainability standards, and rotating the Olympics around a set of cities to reuse venues and infrastructure.

The Olympics never were a matter of sports alone, but an important piece of international power dynamics. In the face of ever-increasing climate change, the Olympics present a unique opportunity by providing a positive example of sustainability. But in order for that to happen, the public must also be aware of what goes behind the scenes.

“I think as sports lovers and Olympics watchers we need to become more critical of the claims to sustainability of these events and not accept them at face value,” said Müller.

The findings were reported in the journal Nature Sustainability.