[29] calculated based on eight natural experiments a ? of 0.1 °C/(Wm?2) resulting in a climate sensitivity of only 0.4 °C for a doubling of the concentration of CO2 in the atmosphere

Does this imply that   of 

climate sensitivity is usually used in the context of radiative forcing by carbon dioxide (CO2), it is thought of as a general property of the climate system: the change in surface air temperature (?Ts) following a unit change in radiative forcing (RF), and thus is expressed in units of °C/(W/m2).

The equilibrium climate sensitivity (ECS) refers to the equilibrium change in global mean near-surface air temperature that would result from a sustained doubling of the atmospheric (equivalent) carbon dioxide concentration (?Tx2).

It is interesting to note that the equilibrium temperature does not depend on the size of the planet, because both the incoming radiation and outgoing radiation depend on the area of the planet.

Because of the greenhouse effect, planets with atmospheres will have temperatures higher than the equilibrium temperature [in the atmosphere component].

The equilibrium temperature is neither an upper nor lower bound on actual temperatures on a planet.

An estimate of the equilibrium climate sensitivity may be made from combining the transient climate sensitivity with the known properties of the ocean reservoirs and the surface heat fluxes; this is the effective climate sensitivity. This “may vary with forcing history and climate state”

The Effective Sensitivity, in degrees per watt per sq meter, is given by:

ES = ?T/(F – A)      (eq. 1)
















 \Delta T_s = \lambda \cdot RF
The terms represented in the equation relate radiative forcing (RF)
 to linear changes in global surface temperature change (?Ts)
 via the climate sensitivity ?.