The IPCC Trick 6

The variation of the Earth surface temperature over day and night (shown in the above picture) with its diurnal temperature range DTR and phase lag L, can be used to determine the heat capacity C and damping A in the following simple model of the Earth-atmosphere system:

• C dT/dt + A T = F sin(t),

where T(t) is the Earth surface temperature deviation from its mean as function of suitably scaled time t, and F = is the mean radiative forcing of the Earth-atmosphere system. Fitting this model to the data DTR = 20 C, F = 240 W/m2 and L = 3 h, we obtain

• A ~ C ~ 0.7 x 240/10 ~ 16 .

An additional forcing of 4 W/m2, by IPCC attributed to doubled CO2, could thus be estimated to require an increase of the mean temperature of 4/16 = 0.25 C, to restore heat balance.

In other words, the observed diurnal temperature variation suggests a climate sensitivity of 0.25 C.

We have now seen two different arguments based on simple models and observation, indicating that climate sensitivity is smaller 0.3 C.

We compare with the climate sensitivity of IPCC of 3 C underlying CO2 climate alarmism obtained by a clever use of the IPCC Trick, which is 10 times larger.