The temperature of the earth's surface is a variable that is constantly changing in response to variations in solar radiance, reflectivity, emissivity and other factors that vary on a daily basis. However, it is possible to calculate an estimate of the overall temperature (T) of the surface by the solar radiation (S), reflectivity (α), and emissivity (ε) (see figure to the left).
QSW = Short wave visible radiation = (1 - α) S / 4
QLW = Long wave infrared radiation = ε σ T 4
α = Reflectivity ; ε = Emissivity
σ = Stefan-Boltzmann constant ; S = Solar Irradiance
The climate change can be determined by the climate sensitivity according to Hansen et al. (1988) and the radiative forcing. The radiating forcing depends on the greenhouse gas concentration.
Reference: Hansen et al., Global climate change as forecast by the GISS's three-dimensional model. J. Geophys. Res. 93, 9341-9364.