Abstract
The results of the analysis of time lags between variations in the global near-surface temperature T and the atmospheric CO \({}_{2}\) content q, obtained using numerical simulations with the IAP RAS–MSU Earth System model for the period 2020–3000 AD, are presented. In these simulations, variations in the energy flux into the climate system associated with natural climate variability, in particular with a period of about 60 years, were taken into account, as well as changes in anthropogenic CO \({}_{2}\) emissions into the atmosphere in accordance with the SSP1-2.6 scenario, extended up to the year 3000 and supplemented with 50-year periodic variations simulating Kondratiev’s economic cycles. It is found that changes in T may both lead and lag behind changes in q, depending on the time interval over which the time lag between T and q is investigated. The results depend on the ratio of the amplitudes of the variations in anthropogenic CO \({}_{2}\) emissions and the variations in the energy flux into the climate system associated with natural variability. The effects observed under their comparable contribution to changes in T are explained using analytical solutions of a system of equations that describe in simplified form the dynamics of the Earth system. The results obtained indicate that, in general, it is not possible to infer the nature of the cause-and-effect relationship between the variables based solely on the time lag between changes in them, without involving physical concepts concerning the nature of their interaction.
