Bicycle: Walking 1 km by bicycle requires an additional 20-25 calories of food, while the production of 1 calories of food requires an equivalent amount of carbon dioxide emissions of 1.5g-2.5g, so the carbon footprint of bicycling by manpower is 30-60g/km.
Electric bicycle: At present, on average, the carbon emission of every 1kwh of electricity generated in the world is about 400g, so the carbon footprint of electric bicycle is about 3g/km. If the carbon emissions of the battery itself in the whole life cycle of the electric bicycle are considered, the carbon footprint of the electric bicycle should be close to 10g/km.
The conclusion of this question is: the carbon footprint of cycling is higher! Even in China, the current carbon emission of power generation is about 800g/kWh, so the carbon footprint of electric bicycles is about 20g/km, which is still lower than that of bicycles.