The figure for the amount of CO2 saved by cycling on this website relates to cycle trips that have been logged for transport purposes only. The statistic relates to the total amount of CO2 released by an average car, of unknown fuel type, which roughly estimates of the amount of CO2 saved by cycling instead of driving. It is calculated as follows
Total units travelled x kg CO2 per unit = total kg CO2
This calculation is the total distance of trips logged for transport purposes times the amount of CO2 released by an average car, which equals the total kilograms of CO2 per mile.
DEFRA's carbon conversion factor for an average car fuel unknown was used. This is 0.29143kg CO2 per mile (0.18109kg of CO2 per kilometre) is provided in 'Greenhouse gas reporting: conversion factors 2017’.
- The carbon calculations on Love to Ride are rough estimates only - there are a whole host of factors that would go into calculating a more accurate figure of CO2 saved from a particular bike trip, e.g. size of car, fuel type, age of car, where the fuel is sourced from, hilly vs flat terrain, the amount of starting and stopping the vehicle would do at traffic lights, etc, etc.
- Producing fossil fuels and cars also uses energy and produces CO2 which is not factored into these calculations. For example, it takes energy to extract crude oil, transport it, refine it, transport it to petrol stations, etc. These additional CO2 emissions have not been included into the calculation, and the amount of CO2 will likely be underreported for most people.
- Other pollutants from cars which pollute the air and are damaging to both the environment and our health are not factored into these calculations (e.g. nitrogen oxides).
- Some people who ride bikes might eat more food as fuel for their riding. Production of food also uses energy and can result in CO2 emissions which vary based on the food (for example, most meat uses a lot more energy and results in more CO2 and methane gas emissions in its production than growing beans does). We have not factored this into the calculation. For human health, we need to exercise. If people didn’t burn calories on their ride to work then they’d work out some other way and burn the calories in any case. We recommend where you can ride your bike, it makes a lot of sense as you can get your recommended level of physical activity, while you get places, enjoy the journey and being outside, save money, save time, and help reduce the amount of greenhouse gases which are warming our planet, changing weather patterns and rising sea levels.
In a nutshell - Riding a bike for transportation does use less energy and emits less CO2 than driving an average car would for the same trip. The figures on Love to Ride give an approximate CO2 figure to represent this saving.