Every four years the Olympic Games take their place as the most widely watched and most expensive human event on the planet and, like most mega-events, potentially the most wasteful.  Extraordinary political and economic leverage is brought to bear as cities compete for the privilege of hosting the games, communities are transformed to accommodate the needs of the games, sometimes without regard to their incumbent plans and character, and much touted economic and infrastructure benefits seldom live up to the extravagant promises. 

Add to those pressures a new awareness of the climate impact of events on this scale. In its Olympic Agenda 2020, the International Olympic Committee announced sustainability goals for future Games, including reducing the number of new venues created by the host cities and reducing the number of participants and officials. 

Moving beyond a post-Games assessment of the environmental impact of each Olympiad, the new directive asked host countries to proactively plan their games to maximize sustainability. It pledged that the IOC would operate as a “carbon neutral” organization and that the carbon footprint of future Games would be significantly reduced—30 percent by 2030 and 50 percent by 2050.

Initially, there was a lot of talk about a carbon-neutral Olympic Games in Paris, but “carbon neutral” is a catchy phrase with a lot of loopholes; genuine carbon neutrality for Paris was not a feasible goal. What the Paris organizers actually promised was a dramatically lower carbon footprint compared to past Games, especially in London (2012) and Rio de Janeiro (2016), which averaged 3.5 million tonnes of CO2. Paris pledged to cut this impact in half, a commitment that aligns with the 2016 Paris Climate Agreement. That calls for a 50 percent reduction in global emissions by 2030. 

Organizers focused on the construction sector as the best chance to achieve significant greenhouse gas reductions.  They tackled this by using existing venues, through the use of recycled and bio-based low-carbon building materials, and by expanding the city’s innovative cooling district—a closed-loop heat exchanger system built in 1991 that uses water from the Seine to cool more than 2,000 buildings in Paris. It is the largest such system in Europe. 

The Olympic Village was built to a standard higher than France’s already progressive green building standard. Designed to be repurposed as affordable housing after the Games, these apartments are cooled by a separate, newly built cooling district. Heat recovered from a data center is being used to heat the Olympic pool. Olympic venues are powered by 100 percent renewable energy.  

Other strategies include heavy promotion of the city’s extensive public transportation system and a focus on plant-based foods and local sourcing of at least 80 percent of the 13 million meals that will be served to participants at the Games. The organizers established a policy of zero single-use plastics at Olympic events and announced their support for four forestry projects to help offset carbon emissions related to the Games. 

These are all great strategies as far as they go, but critics have been quick to point out that the Olympics are not yet addressing the bigger-ticket problems that require more transformative thinking. First is the problem of emissions from spectators’ air travel to and from the Games, a significant portion of the indirect emissions relating to the event. The IOC could address this by limiting the number of seats available for each event, a change that would certainly be unpopular among the athletes and the general public. Others have proposed that the Games be rotated among a selection of cities that have already successfully hosted in the past. This would alleviate the need to build new facilities and infrastructure specifically for the Olympics, which are often poorly managed or underused after the games, and sometimes result in the wholesale displacement of thousands of residents—as happened in Rio de Janeiro in 2016.

Another concern is the use of Olympic sponsorship to greenwash bad environmental behavior by global corporations. The IOC could address this by setting performance standards for sponsors and dropping or avoiding bad environmental actors.  

The post-Games assessment will measure how close Paris came to balancing their 1.5 million tonnes carbon budget. In the broader picture, Paris has also demonstrated that cities need to plan for the climate realities of the present and near future—a lesson with universal significance for urban planning and public health. Paris invested $1.5 billion in improvements to its stormwater management system to improve water quality in the Seine. The prolonged heavy rainfall that swamped the system and endangered the swimming portion of the triathlon events was unusual but on-trend for a warming planet. Athletes were disgusted, and stormwater management engineers labeled the system as outmoded for present and future conditions. 

Friederike Otto, a climate scientist at the Imperial College of London, summed up the larger imperative: “Olympic games are a great opportunity to change cities, as for some reason people accept that athletes need to have a healthy environment, whereas ordinary citizens should live within pollution, traffic, noise and risk their life and health.”