A bicycle will have a smaller carbon footprint when it's made (reduction of material etc) than a car, and lower carbon emission costs as it's used. A car in the

A bicycle will have a smaller carbon footprint when it's made (reduction of material etc) than a car, and lower carbon emission costs as it's used. A car in theory if it's well taken car of can be used for decades, as can a bike. A car will need regular oil changes, new fluids (brakes, etc), new components as parts fail, more equipment is required to work on it. A bike will require cleaning, oiling and maintaining, new tyres as and when needed (probably about the same time scale as a car), but has less components than a car and generally requires fewer tools. Overall whilst a bike isn't carbon neutral to make, it'll produce less over it's life time.