The phase shift between the global surface temperature and the CO<SUB>2</SUB> content in the atmosphere according to simulations with an ensemble of CMIP6 models

The phase shifts between the global surface temperature T and the carbon dioxide content in the atmosphere q obtained in numerical experiments with models of the Earth climate system of the CMIP6 project (Coupled Models Intercomparison Project, phase 6) for the period 1850–2014 are analyzed. It was found that the sign of the phase shift between q and T depends not only on the analyzed time interval, but also on the method of processing the initial series. The initial q series (with a filtered annual cycle) leads in phase the corresponding T series for most models and time intervals. The first differences (inter-monthly increments) for the q series lag in phase the corresponding first differences for the T series by about 10 months with an adequate reproduction of the results obtained by analyzing observational data for recent decades. This means that such delay cannot be an argument against the generally accepted theory of global warming, which links the current increase in temperature with the dominant influence of anthropogenic greenhouse gas emissions into the atmosphere.