I meant "walking TO a foreign city".

For example, imagine that I am taking an intercontinental flight in 8 hours:

- I spend 8 hours flying from London to Mumbai. The majority of my CO2 emissions come from the plane jet engines.

- I spend a month walking between London and Mumbai. The majority of my CO2 emissions come from the food I consume.

Note if I DID fly I would not have spent that 1 month eating, BNBing, using Air Con for a month. Which means that is the CO2 cost of my month-length walk.