Chaotic response of global climate to long-term solar forcing variability

TL;DR

This paper demonstrates that global climate responses to long-term solar forcing are chaotic, with power spectra showing exponential decay rates matching solar activity cycles, revealing the influence of solar variability on climate over millennia.

Contribution

It provides evidence of chaotic climate responses to solar forcing across various timescales and links spectral decay rates to specific solar periodicities, advancing climate modeling.

Findings

Climate exhibits chaotic response to solar forcing across timescales.

Power spectrum decay rates match solar activity periods (11 and 41,000 years).

Results clarify solar variability's role in long-term climate dynamics.

Abstract

It is shown that global climate exhibits chaotic response to solar forcing variability in a vast range of timescales: from annual to multi-millennium. Unlike linear systems, where periodic forcing leads to periodic response, nonlinear chaotic response to periodic forcing can result in exponentially decaying broad-band power spectrum with decay rate T_e equal to the period of the forcing. It is shown that power spectrum of a reconstructed time series of Northern Hemisphere temperature anomaly for the past 2,000 years has an exponentially decaying broad-band part with T_e = 11 yr, i.e. the observed decay rate T_e equals the mean period of the solar activity. It is also shown that power spectrum of a reconstruction of atmospheric CO_2 time fluctuations for the past 650,000 years, has an exponentially decaying broad-band part with T_e = 41,000 years, i.e. the observed decay rate T_e equals the period of the obliquity periodic forcing. A possibility of a chaotic solar forcing of the climate has been also discussed. These results clarify role of solar forcing variability in long-term global climate dynamics (in particular in the unsolved problem of the glaciation cycles) and help in construction of adequate dynamic models of the global climate.