A thermal engineer might tell me there are too many variables to be able to answer the question I'm asking, but I'm just looking for a rough estimate, an educated guess. Here's my question:
How much heat is transferred to the ground from human-built structures including artificial landscapes such as cities?
Another way to put the question is to ask what the estimated difference is between the amount of heat generated by the Earth's surface on its own and the amount transferred to the ground by human-built structures.
See also: How much are oceans warmed by ships, underwater pipelines and cables, and submarines? (December 13, 2018; Pundita)