This final part of the series explores the issue of regulation of Earth’s climate in light of a small, continuing imbalance between energy input from Sol, and outgoing LWIR – the so-called Earth Energy Imbalance (EEI). To reiterate important points from Parts I and II, we are told there is a small imbalance of magnitude 0.76 W/m2, but the certainty of this number appears too optimistic. Even by the estimation of its proponents it doesn’t include all sources of bias. The so-called components of feedback into the climate system, which are responses to this imbalance, may not be any better known or understood than EEI itself; the list of likely responses is possibly incomplete.