Climate scientists evaluate urban growth (and thus UHIs) only on increases in fossil fuel use (and thus greenhouse gas emissions), and not on heat increase. If DHE has ever been considered in the past from the global warming perspective, it has usually been estimated as unimportant. At most, one calculated (also because one strictly limited that estimation to the heat effect of the primary energy use, and did not include fires, volcanoes, underground coal and peat fires, scorching, and nuclear waste heat) a global average effect between 0.02 and 0.04 W m-2, so well, what does that really mean considering the solar input that can be 1000 W m-2 during the day, and the approximately 2.83 W m-2 (well-mixed greenhouse gas ERF) anthropogenic radiative forcing due to greenhouse gases.