Choosing a bike over a car just once a day reduces an average citizen’s carbon emissions from transport by 67%, according to research led by University of Oxford transport professor Christian Brand. 


Firstly we have to consider how much carbon is released into the atmosphere every time someone drives. The average carbon dioxide (CO2) emissions from new passenger cars registered in the European Union (EU) in 2018 increased for the second consecutive year, reaching 121 grams of CO2 per kilometre.



Let's remember that over half of journeys are taken by car (52.6%) in Ireland, either as driver or passenger, whereas for longer journeys of eight kilometres or more, nearly nine out of ten (87.1%) were by car, either as driver or passenger. 



Therefore, even if you drive only 20km (say the distance between Phibsborough and Dundrum), you will emit about 2.5kg of CO2 into the atmosphere, on average. If this is your commute / creche trip / general distance a day, this is a staggering 12kg a week, 630kg a year. And that obviously excludes all other trips.

Let's also remember than carbon stays in the atmosphere for hundreds of years (between 400 and 1000), and that it is the accumulation that causes the heating we are now experiencing. 


During the study mentioned above, around 4,000 people living in London, Antwerp, Barcelona, Vienna, Orebro, Rome and Zurich were obversed. Over a two-year period, participants completed 10,000 travel diary entries which served as records of all the trips they made each day, whether going to work by train, taking the kids to school by car or riding the bus into town. For each trip, the carbon footprint was calculated.

Strikingly, people who cycled on a daily basis had 84 per cent lower carbon emissions from all their daily travel than those who didn’t.


It was also found that the average person who shifted from car to bike for just one day a week cut their carbon footprint by 3.2kg of CO2 – equivalent to the emissions from eating a serving of lamb or chocolate, or sending 800 emails.

Finally, when the researchers compared the life cycle of each travel mode, taking into account the carbon generated by making the vehicle, fuelling it and disposing of it, they found that emissions from 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.

This is partly because electric cars aren’t truly zero-carbon – mining the raw materials for their batteries, manufacturing them and generating the electricity they run on produces emissions. Furthermore, electric cars will not solve the other issues we experience on our roads and our cities: congestion, road deaths, road aggression, footpath parking etc. 

We knew all this already, but quantifying the carbon saved is very important. Our daily choices have an impact on the general well being of the Earth. Active travel is cheaper, healthier, better for the environment, and no slower on congested urban streets. Active travel can contribute to tackling the climate emergency earlier than electric vehicles while also providing affordable, reliable, clean, healthy and congestion-busting transportation.






We also estimate that urban residents who switched from driving to cycling for just one trip per day reduced their carbon footprint by about half a tonne of CO2 over the course of a year, and save the equivalent emissions of a one-way flight from London to New York.