Unless you are walking from country to country, you are using fossil fuels.
Many people don’t have the “privilege” to trek the world doing nothing.
It is more realistic and less environmentally destructive to do nothing locally and think globally.
You might want to consider the lobster:
“To be a mass tourist, for me, is to become a pure late-date American: alien, ignorant, greedy for something you cannot ever have, disappointed in a way you can never admit. It is to spoil, by way of sheer ontology, the very unspoiledness you are there to experience, It is to impose yourself on places that in all non-economic ways would be better, realer, without you. It is, in lines and gridlock and transaction after transaction, to confront a dimension of yourself that is as inescapable as it is painful: As a tourist, you become economically significant but existentially loathsome, an insect on a dead thing.”