In
climate science,
radiative forcing or
climate forcing is defined as the difference of
insolation (
sunlight) absorbed by the Earth and energy radiated back to space. Typically, radiative forcing is quantified at the
tropopause in units of
watts per square
meter of the Earth's surface. A positive forcing (more incoming energy) warms the system, while negative forcing (more outgoing energy) cools it. Causes of radiative forcing include changes in insolation and the
concentrations of
radiatively active gases, commonly known as
greenhouse gases and
aerosols.