Riding a Bike Has One-Tenth the Impact of an Electric Car

A full life-cycle analysis shows that EVs still have a significant carbon footprint.

Waiting for the light in Copenhagen
Bikes and buses in Copenhagen.

Lloyd Alter

A recent study with the unexciting title The Climate Change Mitigation Effects of Daily Active Travel in Cities comes to the unsurprising conclusion that "cyclists had 84% lower CO2 emissions from all daily travel than non-cyclists." The lead researcher, Christian Brand, jazzed it up a bit in his summary in The Conversation, titling it, Cycling Is Ten Times More Important Than Electric Cars for Reaching Net-Zero Cities. The main reason that cycling is so much more effective is our old Treehugger standby, the upfront carbon emissions (or embodied carbon) of the materials that go into the cars and batteries. Brand writes:

"The emission savings from replacing all those internal combustion engines with zero-carbon alternatives will not feed in fast enough to make the necessary difference in the time we can spare: the next five years. Tackling the climate and air pollution crises requires curbing all motorised transport, particularly private cars, as quickly as possible. Focusing solely on electric vehicles is slowing down the race to zero emissions."

Brand also recognizes, but doesn't measure, the impacts of carbon-intensive infrastructure, the roads, bridges, and parking, that go along with a car-dependent lifestyle – but notes that "one way to reduce transport emissions relatively quickly, and potentially globally, is to swap cars for cycling, e-biking and walking – active travel, as it’s called."

The study used data from well-known research, the Physical Activity Through Sustainable Transport Approaches study with the ridiculous acronym PASTA; we have written about it previously on Treehugger but you can imagine what comes up in a search. The PASTA study connected the mode of transport to health; the new study connects the data to carbon emissions.

Unlike other research we have discussed, which just looked at the grams of CO2 per kilometer for each of the modes of transport, using the PASTA data lets the researchers determine the cumulative savings from changing modes because they know how far people are going in each city examined. This provides interesting data about why people are traveling: "While travel to work or place of education produced the largest share of CO2 emissions (37%), there were also considerable contributions from social and recreational trips (34%), business trips (11%) and travel for shopping or personal business (17%)."

The savings in carbon emissions from shifting travel modes were significant; going "from car to bike decreased life cycle CO2 emissions by 3.2 kgCO2/day." The study authors conclude with a nod to the pandemic:

"Active travel has attributes of social distancing that are likely to be desirable for some time. It could help to cut back transportation energy use, CO2 emissions and air pollution while improving population health as confinement is eased. Therefore, locking in, investing in and promoting active travel should be a cornerstone of sustainability strategies, policies and planning to meet our very challenging sustainable development goals that are unlikely to be met without significant mode shift to sustainable transport."

The study never actually mentions electric vehicles; Brand infers this in his article in The Conversation, noting that "cycling can be more than 30 times lower for each trip than driving a fossil fuel car, and about ten times lower than driving an electric one."

Lifecycle greenhouse gas emissions for conventional and electric vehicles (by country) in grammes CO2-equivalent per kilometre,
Lifecycle greenhouse gas emissions for conventional and electric vehicles in grammes CO2-equivalent per kilometre,. Carbon Brief

I covered this issue in my book, "Living the 1.5 Degree Lifestyle," albeit with less sophisticated data, and just looking at lifecycle data per kilometer found that "bicycles emit 5 g, e-bikes emit 25 g, buses emit 110 g, and cars emit 240 g CO2e per person kilometer. Clearly, e-bikes emit little more than conventional bicycles and far less than cars and buses, even when considering manufacturing, use, and disposal." Other studies that I have quoted in Treehugger have found that a Tesla Model 3 with batteries made in their most efficient giga-factory had lifecycle emissions of 127 grams per person kilometer, about half of a conventional car. However all of these numbers are such rough estimates; I found others that said a regular bike had a footprint of 20 grams, and an e-bike just 21. The conclusions are similar: bikes and e-bikes have a footprint that is a fraction of a car or an e-car.

I have written in my book that “when you start looking at the world through an upfront carbon lens rather than operating carbon, everything changes.” An electric car is now only half as bad as a gasoline-powered car, and that's not good enough to get us where we have to go to stay under 1.5 or even 2 degrees. So whatever methodology one uses, the conclusion is the same; here is the one from Brand:

"So the race is on. Active travel can contribute to tackling the climate emergency earlier than electric vehicles while also providing affordable, reliable, clean, healthy and congestion-busting transportation."
View Article Sources
  1. Brand, Christian, et al. "The Climate Change Mitigation Effects of Daily Active Travel in Cities." Transportation Research Part D: Transport and Environment, vol. 93, p. 102764, doi:10.1016/j.trd.2021.102764

  2. Brand, Christian. "Cycling is ten times more important than electric cars for reaching net-zero cities." The Conversation, 2021.