Nonadditive Tsallis entropy applied to the Earth’s climate

The concepts of nonextensive statistics, which has been applied in the study of complex systems, are used to analyze past records of the Earth’s climate. The fluctuations within the record of deuterium content (hence temperature) in the last glacial period appear to follow a q-Gaussian distribution. Analyses of the time-dependent nonadditive entropy indicate transitions between different complexity levels in the data prior to the abrupt change in the system dynamics at the end of the last glaciation. Different fluctuation regimens are evidenced through wavelets analysis. It is also suggested that time-dependent entropy analysis could be useful for indicating the approach to a critical transition of the Earth’s climate for which theoretical models are in many cases not available.