2024 Olympic Games, gold medal for sustainability?

The organizing committee for the Paris Olympics had initially planned to limit emissions from this event to 1,58 tCO2e, which would more or less halve the carbon footprint of the London Olympics in 2012 (3,3 million tCO2e) and Rio in 2016 (3,6 million tCO2e). Although the real impact can only be truly assessed at the end of the games, the study carried out by Greenly focuses on the emissions avoided by upstream decision-making.

Olympic sites: renovation of existing buildings and sustainable construction

One of the strengths of the candidacy is the use of existing infrastructure, unlike previous host cities, whose buildings erected on this occasion were subsequently under-exploited. The London Olympics had already attempted to respond to this problem, by combining new constructions with the use of existing structures. Paris, for its part, should reuse 95% of existing sites for almost all of the events.

For new construction, developers have shown ambition by trying to adopt a low-carbon strategy by deploying renewable energies and using sustainable materials such as lumber and low-carbon concrete. Thus, the balance per square meter built should be 0,7 tCO2e, compared to 1 tCO2e for average use. This responsible approach was adopted for the construction of the Olympic Village with measures such as the use of timber and low-carbon concrete. All of the measures would have allowed a 30% reduction in emissions compared to an equivalent conventional construction. Especially since once the competition is over, the Olympic Village will become a district hosting housing, shops, public facilities, offices and green spaces which will meet the long-term needs of 6.000 residents, thus extending the duration life of the place.

Other initiatives such as the use of river transport via the Seine - to transport the rubble excavated during the construction of the Olympic Village - should also make it possible to avoid the 3.000 tCO2e which would have been generated by transport by truck.

Rise of renewable energies

Paris 2024 aims to make significant progress in reducing emissions with regard to energy consumption. By promoting renewable energies and the installation of retractable electric billboards, Paris 2024 is counting on a saving of 13.000 tCO2e. “Usually”, sporting and cultural events use diesel generators.

Furthermore, certain key sites such as the Olympic Village and the Aquatics Center have been designed to meet part of their energy needs using renewable energies. Solar panels and a photovoltaic fabric canopy will contribute to local electricity production. There are also plans to install a floating solar power plant on the Seine, equipped with 720 m² of photovoltaic panels to supplement the supply of renewable energy.

Circular and responsible economy

Games organizers have sought to adopt a responsible purchasing strategy to combat unsustainable consumption - a spend estimated at around €2,5 billion on goods and services. All furniture purchased is believed to have been designed with sustainability in mind, to support long-term use and the inclusion of circular economy practices. As such, the 11.000 seats at the Saint-Denis Aquatic Center were, for example, made from recycled materials.

Even if catering represents 1% of the games' total emissions, the organizers wanted to emphasize the importance of applying best practices. Thus, with 13 million meals served during the games, the offer of vegetarian dishes will be reinforced, reaching 50% of the offer offered in total. In addition, 80% of food waste will be composted. The carbon footprint of each meal could be reduced by around 51%, thus emitting 1 kgCO2e compared to 2,04 kgCO2e for the average meal of a French person. In total, this would save more than 13.520 tCO2e.

Between eco-mobility and international flights

The largest carbon footprint will come from spectator transportation. It is estimated that more than 15.000 athletes, 9.000 journalists and 15 million spectators, including 1,5 million from abroad, will travel to the games. Although the attendance figures for the Paris Olympics are not yet known, Greenly based himself on the lessons learned from those in London. During these games, around 471.000 trips were made to the UK - mainly for the games (to Rio it was 410.000).

To calculate emissions linked to spectator travel, Greenly proposed several hypotheses regarding the modes of transport used by visitors from different countries, depending on their distance from Paris. In these hypotheses, spectators from neighboring countries such as the United Kingdom, Germany and Italy would prefer half the train - the other half, the plane, while spectators from the United States, Canada or Japan, would find themselves obliged to take the plane. Based on these assumptions, Greeny estimates transport-related emissions at around 813.000 tCO2e, roughly equivalent to the average annual carbon footprint of 90.333 French people.

Nights in the capital

During the Olympics, the total number of nights attributable to spectators was estimated at 13.657.652. To estimate the environmental impact of these stays, Greenly based itself on the carbon footprint of a night in a room in a 3-star hotel in France (according to the methodology of the Hotel Carbon Measurement Initiative , estimating the emission factor at 6,2 kgCO2e). Greenly therefore estimates emissions linked to spectator accommodation at around 85.000 tCO2e.

Seine cleaning operation

The cleaning of the Seine, a 1,4 billion euro initiative, aims to have a positive impact on the fauna and flora, and allow the reopening of the river to swimming, prohibited since 1923. Each year, more than 360 tonnes of waste would be removed from the river. Over these two decades, however, the improvement of infrastructure would have made it possible to reduce the wastewater discharged into the Seine by 90%. The new reservoir, with a capacity of 45.000m3, located near the Austerlitz station, constitutes a promising solution in the management of excess rainwater. But despite these achievements, problems persist.

Recent research has established that the process of degradation of plastics - particularly when exposed to UV light - could be at the origin of the emission of powerful greenhouse gases such as methane, which contribute to the worsening of climate change. In addition, microplastics dumped into the oceans disrupt the carbon absorption capacities of phytoplankton, while affecting their metabolism and reproduction. With phytoplankton responsible for around 45% of Earth's oxygen production, these disruptions compromise a vital regulation of carbon dioxide levels and oxygen production.

Carbon offset strategy

Despite the numerous measures taken to reduce the carbon footprint of the Olympic Games, certain emissions remain unavoidable. The organizers have also committed to fully offsetting them by supporting carbon offset projects. However, several reservations are expressed regarding the credibility of this strategy.

For Tommy Catherine, Climate Expert at Greenly: “Even if the games committee promises to be meticulous in the choice of projects, they are often criticized for their lack of efficiency and transparency. Unfortunately, uncertainties remain about whether these projects actually neutralize or reduce emissions. There is a certain skepticism, reinforced by the idea that some could seek to evade this approach, and pursue activities harmful to the environment under the cover of so-called “environmental compensation”. This combination of variable accounting methods, lack of standardization in project evaluation and potential for negative impacts on local communities and ecosystems continues to fuel criticism of carbon offsetting. »

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