The Rule of Climate Change.
It seems, to this non-expert, that a simple rule has been forgotten, even by the supposed 'experts' on the climate, that, if we reproduce the atmospheric chemistry of the past, other things being equal, we will reproduce the climatic conditions of the past. This rule deserves, and needs , to be reiterated, and emphasised, in all the introductory textbooks on climatology. So it is that the atmospheric chemistry of the Mid-Piacenzian Warm Period (MPWP) of the Pliocene Epoch, 3.35-3.15 million years ago (Mya) is being reproduced in this decade, with the orbital configuration of the Earth no different to then (or, at any rate, insufficiently different to have any appreciable impact) and the Sun's luminosity actually brighter by between 0.0286-0.0345% (the gain in luminosity being 0.01% every 1.1 My). See: de la Vega, et al (2020) ; Schr รถ der and Smith (2008) , p.157 (p.3, pdf.). If the maximum atmospheric CO2 level in the MPWP was 428 ppm, and the mean annual global near-sur