Comment by rcxdude

Cities probably have a significantly larger effect on the way that energy flows around the earth than renewable power generation does. It's relatively easy to change how much a very large amount of heat moves in comparison to how easy it is to harness energy into usable work. (See also why the greenhouse effect from CO2 emissions is such a big deal in comparison to basically any other thing that humans have done, as far as the energy balance of the earth is concerned. CO2 is responsible for about 20 times more energy being absorbed by the earth than humanity uses in total, from any source)