Vertical molar fraction of the gases on Uranus (left) and Neptune (right) used by the model. Collision-induced absorptions and emissions of H₂ and He contribute to radiative heating and cooling throughout the entire atmospheric column, as absorption and emission by methane (except on Uranus, where its abundance becomes insignificant at pressures below ~10 Pa). The other hydrocarbons are active only in the stratosphere for pressures between ~1 hPa and ~7 Pa on Uranus and below than ~10 hPa on Neptune.