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The energy transition in transportation is undoubtedly one of the most complex challenges of the century. Where does France stand on this issue? Can we hope to achieve carbon neutrality in transportation by 2050? Will technology be our salvation, and is a “green airplane” really possible? These are all questions to which Aurélien Bigo gave a candid response to Tolt's microphone for our podcast “Want a hit?” (the podcast that gets you hooked on trains), in partnership with SNCF Connect.
Independent researcher engaged in the study of energy transition in transportation, In his dissertation (defended at the Institut Polytechnique in 2020), Aurélien Bigo examined how we could achieve our climate goals in the transportation sector, particularly in France. After working at ADEME to help develop future scenarios Transition 2050, he now focuses on the transitions in our mobility through his two complementary approaches: research and public outreach.
In this article, we'll give you a summary of the key ideas discussed in the episode (but we highly recommend that you listen to the whole thing). Diving into one of the greatest challenges of our time : The Impact of Our Travel on the Climate!
Today, transportation (of passengers and freight) accounts for approximately 30 to 33 percent of greenhouse gas emissions in France. Taking first and second place on the podium: the car and the airplane.
Cars, which dominate two-thirds of trips in France, are the main sources of these emissions. To better understand the current situation, Aurélien Bigo suggests we take a look back:
“In just one century, we’ve gone from from walking to driving as the primary mode of transportation ! This has implications for travel time, the number of trips, and the number of kilometers traveled.”
Today, walking accounts for more than a quarter of our trips, in front of public transportation—including trains—which accounts for only 10 to 15 percent of trips, while bicycles account for only 3 to 4 percent.
Over the course of a century, the French have maintained an average of one hour of commuting per day, but the dramatic increase in transport speed (10 to 12 times faster) now allows them to travel An average of 50 kilometers per day, compared with 4 to 5 kilometers previously. In short, we spend just as much time commuting every day as we did 100 years ago, except that we travel faster and therefore farther.“Back then, we could get from one city to another in 3 or 4 hours. Now, we can travel to another region (by car) or even to another continent (by plane)”.
Right behind cars, airplanes rank second in terms of kilometers traveled and greenhouse gas emissions in France (about one-third for freight transport and two-thirds for passenger transport).
The airline industry thus accounts for 7% of CO2 emissions in France. And on the international level, it's the the only sector that has not begun to reduce its emissions.
Source: CITEPA Secten 2019 / Aurélien Bigo
And despite a slowdown during the health crisis, its use continues to increase.
As Aurélien Bigo points out, "The plane accelerates to a excess mileage". " Although comparable to a car in terms of emissions per kilometer, it allows you to travel much more distance in a short amount of time, drastically increasing overall emissions per trip.
In the Carbone4 article “Common Misconceptions About Aviation and Climate”, we can see the differences in “carbon intensity” by mode of transportation for a 400–1,000 km trip, in the short term (excluding construction) and the long term (including construction):
gCO2e/passenger-km - Source: Carbone4.com - “Common Misconceptions About Aviation and Climate”
The aviation sector is generally credited with 2% of global CO2 emissions. But that figure doubles when you include non-CO2 effects, such as contrails and nitrogen oxide emissions! These impacts, though short-lived, accumulate as air traffic grows and amplify the impact on the climate.
While aviation industry professionals claim to be aiming for carbon neutrality by 2050, Aurélien Bigo has several reservations.
Article
Decarbonization of air transport: when conventional wisdom goes out the window
The idea that technological innovations alone will be enough to achieve carbon neutrality is encouraging. But it is also increasingly contested.
Among the most common ones, there's a lot of talk about the sustainable aviation fuels (SAF). However, according to the researcher, they have obvious limitations:
Biofuels : Although they can reduce emissions, their production requires limited resources. In particular, biomass (all materials derived from plants: wood, vegetable oils such as rapeseed oil in biodiesel…), the use of which often in competition with food uses and biodiversity !
Rapeseed Plantation (rapeseed oil is widely used for biodiesel in Europe)
Synthetic Fuels : They require large quantities of hydrogen and CO2, produced using low-carbon electricity. However, the demand for electricity would be massive: Achieving carbon neutrality with these fuels would require the equivalent of half the current electricity production of a country like Germany or France !
"For cars or road transport, for example, these synthetic fuels are not the preferred choice because it is necessary to It takes 4 to 5 times more electricity to power a car running on synthetic fuels "than for a battery-powered electric car. So if the aviation sector is currently considering these synthetic fuels despite everything, it is solely because there aren't really any other alternatives available for decarbonizing long-distance travel."
As for hydrogen and electric vehicles : These solutions are limited to short trips and remain uncertain for medium- and long-haul flights. They also raise questions about sustainability : “There are several sectors that will need to become more electrified as part of this transition. So setting aside such a massive, significant portion of electricity generation for air travel raises serious questions.” And when it comes to hydrogen, we recommend that you this article to better understand the issues involved.
And if you'd like to learn more, feel free to read our article on Common misconceptions about decarbonizing the aviation sector.
For the researcher, the conclusion is clear. As Tolt summarizes: “ "Believing in green aviation today is like living in a rainbow."
“ The aviation industry has gone from being climate-skeptical to climate-optimistic to tech-solutionist. “But it’s clear that today’s techno-solutionism isn’t going to work.”
"From now on, up to the level of the General Secretariat for Ecological Planning (SGPE) - which reports to the prime minister - projections for air travel are being revised downward more and more. The scenarios don't add up: demand for biomass and electricity is too high compared to the amount of production we can reasonably expect", and we won't be able to achieve carbon neutrality by 2050 this way."
To learn more, we recommend that you this interview with Aurélien Bigo in Polytechnique Insights.
Faced with inadequate technological solutions and energy constraints, a sobriety planning seems essential. Finally, as the Climate Action Network points out, the question is no longer “Should we "reduce air traffic" but " How "How can we reduce air traffic in a fair and effective way?"
Aurélien Bigo presents a key concept here: the fuel efficiency per kilometer, which consists of limiting the distances traveled rather than simply decarbonizing transportation. While air travel encourages excessive travel, choosing not to fly for shorter trips can drastically reduce emissions.
A vision that aligns with that of Jean-Marc Jancovici (who was also a guest on the podcast), who encourages us to rethink the concept of getting away from it all and travel to move toward a lifestyle of simplicity that is chosen (rather than imposed).
In France, trains already account for 10 to 15 percent of trips, And people have never traveled as many kilometers by train in France as they do today (especially since the development of the TGV). But is this a boom in rail travel or a boom in mobility? For Aurélien Bigo, the question is this: "To what extent does this 'more train' mean 'fewer flights' and 'fewer cars'?"
It also encourages “intermodality” (“Personally, I combine taking the train with biking.”) to meet the needs of daily or long-distance travel without having to use a car or plane.
As the researcher reminds us, this transition will require a systemic and collective approach, combining innovation, ambitious policy reforms, and behavioral change. And when it comes to behavior, since the A reduction in air and road traffic seems inevitable To meet climate goals, the train is emerging as a top choice!
And through their stories, the guests of "Want a hit?" ...show us that traveling by train isn't just a sustainable alternative. It's also an adventure in its own right that invites us to rethink the way we travel!
To make sure you don't miss a single episode and get plenty of inspiration from our guests, feel free to Subscribe to the podcast on your favorite streaming platforms. Thanks to our partner SNCF Connect, the leading app for trains and sustainable transportation that helps more than 15 million users plan their trips in France and Europe.
And for follow Aurélien Bigo's work For more information on the changes in our mobility patterns, visit LinkedIn, on its dedicated page on the Energy and Prosperity Chair, or in his book "CARS - Fake or not?" !
Issue du monde de la communication et des médias, Sophie est Responsable éditoriale chez HOURRAIL ! depuis août 2024. Elle est notamment derrière le contenu éditorial du site ainsi que La Locomissive (de l'inspiration voyage bas carbone et des bons plans, un jeudi sur deux, gratuitement dans ta boîte mail !).
Convaincue que les changements d’habitude passent par la transformation de nos imaginaires, elle s’attache à montrer qu’il est possible de voyager autrement, de manière plus consciente, plus lente et plus joyeuse. Son objectif : rendre le slow travel accessible à toutes et tous, à travers des astuces, des décryptages et surtout, de nouveaux récits.
