The modern climate is the climate of the current century with its characteristic features. The ocean and the atmosphere, however, are considered as two of the most important components of the climate system. The dynamics and thermodynamics of these spheres reflect the current perturbations of the planetary environment on intra-decadal (2–8 years) and multi-decadal (20– 60 years) time scales. Quasisynchrony and globality of the phenomena occurring in the modern climate system are provided and accompanied by planetary scale structures identified both in the atmosphere and in the ocean: respectively, the Global Atmospheric Oscillation (GAO) and the Multi-decadal Oscillation of the Heat content in the Ocean (MOHO). A characteristic feature of the modern climate dynamics is its observed multidecadal rhythm with a period of about 60 years. The rhythm of 1940–1999 was a two-phase structure, in which the initial phase (1940–1974) was essentially continental, and the final one (1975-1999) was relatively wet. The transition of the climate from the continental phase to the humid phase in the mid-1970s turned out to be “sudden” and was recognized as a climate shift. The search for the source of the observed variability of the modern climate made it possible to establish that the heat content of the active upper layer (AUL) of the World Ocean (WO) demonstrates multidecadal phases of heat accumulation and heat discharge, consistent with multi-decadal phases of climate disturbances. It should be noted that the heat accumulation phase of the WO AUL corresponds to a continental climate, and its thermal discharge corresponds to a relatively humid one. The mechanism of the observed multidecadal phase variability of the modern climate is the planetary intrasystem redistribution of heat between WO and continents, in which the general circulation of the atmosphere plays the role of a mediator.