The third major cause of UHIs has very different science than CC, and is a local rather than a global phenomenon. Humans convert fuel into work, with heat as a byproduct. We have gotten ever more efficient at burning fuel, especially hydrocarbons, but the amount of combustion has increased with the size and progress of civilization. A study has shown that in some American cities, waste heat likely accounts for a third of the UHI effect. Conventional suburban development in America does not compare well to compact, walkable, bike-able, mixed-use and transit-oriented neighborhoods, which reduce travel distances, miles driven and fuel burned. The ubiquitous glass skyscraper takes a great deal of energy to heat and cool. It is clear that global demand for air conditioning will continue to grow for several decades. A building’s physical size is very consequential, not only in terms of energy to heat, light and cool it, but also the energy that goes into its materials and erection – all of which produce waste heat. Renewable energy systems, which don’t combust fossil fuels to produce electricity, are a key component of reducing waste heat. Jevons Paradox is explained.