>>1404788>>1404817>>1404818The key point on environmental impact is that burning fossil fuels releases trapped CO2 while growing crops and burning them (metabolism) is a renewable cause of CO2 emission.
(assuming that the driver and rider are vegetarians)
This means that the CO2, which gets released by metabolising crops, was taken out of the air before during the growth phase of the crop. So its no additional CO2 load on the atmosphere.
This whole discussion starts to get interesting when the car is powered from renewal energy sources such as bio-ethanol made from crops.
There are other important things to consider here: The driver also metabolises while driving, so its the drivers emission + the vehicles emissions for the driving.
The cyclists metabolism and emission footprint is not much above normal considering a casual rider (like 95% of riders)
The question should not be projected on a pro racer with 3x the metabolism and calorie intake compared to a casual rider.
