Statistical analysis of the connection between geomagnetic field reversal, a supernova, and climate change during the Plio–Pleistocene transition

A significant change in the Earth’s climate occurred during the Pliocene–Pleistocene transition. Different external and internal forcings were interrelated in such a way that they promoted the cooling of the climate and environmental changes. We analyzed these changes using a mathematical and statistical approach based on a new algorithm combining Artificial Intelligence and the new multiple cross-wavelet analysis. Although the geomagnetic field (GF) paleointensity showed oscillations over time and not a uniform decay, the results of the Radial Basis Function Artificial Neural Networks showed a long periodicity oscillation with a downward trend practically throughout the Plio–Pleistocene transition. A weakened GF could have allowed an increase in the flux of galactic cosmic rays (GCR) penetrating the Earth’s atmosphere. This led us to hypothesize that, during the Plio–Pleistocene transition, the increase in GCR could have induced a gradual increase in clouds and, therefore, the albedo intensified, causing a progressive decrease in the Earth's surface temperature, as recorded in different paleoclimatic reconstructions of the Plio–Pleistocene. In addition to the known variations in orbital parameters, the GF behavior (the Gauss–Matuyama reversal) and a feasible influence of a coetaneous near supernova event (at less than 100 pc), could have reinforced the climatic forcings towards glacial conditions during the Plio–Pleistocene transition (~ 2.5 Ma).