claim: Elementary radiative-transfer calculations demonstrate that a natural surface global brightening amounting to ~1.9 Wm–2 over the 18-year period of study would be expected – using the IPCC’s own methodology – to have caused a transient warming of 1 K (1.8 F°).
evidence: Solar irradiance is about 0.9 W/m2 brighter during solar maximum than during solar minimum, which correlated in measured average global temperature over the period 1959-2004.
category: Climate sensitivity