Isoprene and Evapotranspiration Time Series Provide Further Empirical Evidence for a Natural Global Atmospheric Temperature Control System

There is evidence that an increase in plant-emitted isoprene causes an increase in cloud condensation nuclei, and is one way in which an increase in cloud cover occurs. Similarly, an increase in plant-emitted water vapour from transpiration can cause an increase in wind speed, which can transfer more heat out of the atmosphere into the ocean. Each of these pathways can reduce global atmospheric surface temperature. With this background, we investigated whether there was empirical evidence that isoprene and transpiration were components of the natural atmospheric temperature control system for which we have previously provided empirical evidence[1][2]. Using the statistical hypothesis test of Granger causality as well as autoregressive distributed lag (ARDL) modelling we found generally very highly statistically significant evidence that isoprene and transpiration are components of the control system, and that they are placed in the early part of the control system chain immediately after the lead element, the global biota. Prior evidence[1][2] indicates that the information used by the control system to detect a disturbance to the setpoint of its outcome – global surface temperature – is a combination of the level of atmospheric CO2, its integral, and its first and second derivatives. Evidence is presented that this information pattern is created in each plant that participates in the control system and is impressed on isoprene and water vapour before they are emitted from the stomata of leaves to enter the atmosphere.