Glossary

Radiative forcing refers to a change in the net energy balance (incoming energy minus outbound energy; expressed in watts per square metre: Wm^-2) at the tropopause (border between the troposphere and stratosphere) due to changes in an external forcing factor affecting the climate system, e.g. a change in the concentration of carbon dioxide or solar radiation. Radiative forcing is calculated by keeping all tropospheric qualities constant at their steady-state values and after the stratospheric temperatures, if they change, have adapted to the radiative equilibrium. Radiative forcing is referred to as “direct” when no change is observed in the stratospheric temperatures. Radiative forcing should not be confused with cloud (radiative) forcing, a similar term used to describe clouds’ influence on incoming radiation at the outer limit of the atmosphere.