A carbon footprint is primarily based around the means you use to travel and the resources you use to exist yeah? I can only imagine he plans to camp a lot, walk a lot and basically all hippy on us. From what I know he'll be attending some very high caliber events next year and while it may be a little less flying and driving, he'll still be flying and driving.
Travelling might be part of it. However it could be more based around the effect the world cup has overall. Everything that is manufactured or consumed by the team, individual, event, etc will contribute to the carbon footprint he is, was or thinks he is associated with. I don't know how many are used per event or season but I could imagine that it could start to add up if you are using many frames, wheels, brakes, tyres, over a season. These parts probably don't get a full life on the bike either, where we might use something until it requires replacing, they cant risk doing a race run with parts that are 60% worn and might let them down.(maybe the get reused for training). Its not just his own foot print either as if he goes to an event that means that his mechanic, coach, phisio, fans, or whatever support goes with him and all of or part of their footprints are added to his own. (They are there because he is there.)
Even by him retiring all of those things will still happen, just for whichever rider fills his spot, but his own footprint or wastage could be significantly reduced. If he now travels to do something maybe it is now on a smaller scale and less frequency that he feels better about his impact.
Still the whole thing pales in comparison to say the footprint of a Formula 1 driver.
