Climate prediction for the extratropical northern hemisphere for the next 500 years based on periodic natural processes

Five paleoclimatic reconstructions for the extratropical Northern Hemisphere are decomposed into quasiperiodic variations using the spectral analysis methods. The existence of ∼1000-, ∼500-, ∼350-, and ∼200-year periodicities is established which define the climatic variability over the past four millennia. Based on the identified quasiperiodicities, the climate forecast for the Northern Hemisphere extratropical zone is obtained. The forecast demonstrates that the currently observed warm climate will generally be kept for 500 years. However, the strongly pronounced trend towards the gradual cooling is expected in the 22nd century.