To the theory of the Pliocene – Pleistocene and Holocene climate

Abstract

In this paper, an attempt to explain the main features of the planetary climate dynamics over the past ~5 Myr is made. In particular, a general cooling from the Pliocene to the Pleistocene, predominant climate variations with periodicities of 100, 41, 2319 thousand years and the continuous nature of the spectrum are discussed. As a result, it was shown that the decrease in temperature is due to a monotonous decrease of the CO2 concentration during the Cenozoic era. This led to glaciations and restructuring the predominant climate rhythmicity of from 41ka to 100 ka years cycles with an increase in the amplitude of fluctuations. 41 ka, 23 ka and 19 ka year cycles are associated with variations in the position of the planet in its orbit and the elongation of its orbit. 100 ka rhythms exists due to the stochastic resonance of internal variability and eccentricity variations. The continuous spectrum of oscillations reflects the transfer of energy along the spectrum from the energy-carrying range due to the direct cascade, which has a Kolmogorov character. At the same time, energy transfer to the low-frequency region (inverse cascade) is also possible and associated with the effect of the Brownian process. Climate change on a century scales is associated with the inflow of energy from two sides, from long-term and short-term processes. In the first case, it is transfer from the energy-carrying Milankovitch cycles, and in the second case, it is pumping from high frequencies. Therefore, these variations, in a certain sense, are the most difficult for causal analysis. The DansgaardOeschger and Heinrich oscillations, which are included in the range of centenary variations, stand apart, having a specific oceanic-glacial nature.