Observational evidence that a Gaia-type feedback control system with proportional-integral-derivative characteristics is operating on atmospheric surface temperature at global scale

Abstract: The Gaia hypothesis (Lovelock and Margulis, 1974) proposes that there is a control system operating at global level that regulates climate and chemistry at a habitable state for the biota. Here we provide statistically significant observational evidence that a feedback control system moderating atmospheric temperature is presently operating coherently at global scale, that is to say, observational evidence for Gaia. Further, this control system is of a sophisticated type, involving the corrective feedback not only of a linear error term but also its derivative and its integral. This makes it of the same type as the most commonly used control system developed by humans, the proportional-integral-derivative (PID) control system.