2400-year solar cycle ascertained by us in the long-term series of various natural characteristics (e.g. the radiocarbon content in samples of well-known ages, oscillations of the sea and ocean levels etc.) includes three parts roughly equal in duration: a phase of high activity, a phase of depression and a phase of moderate activity. In climate oscillations, which are connected with this cycle, the next phenomena are established: a little climatic optimum, a little Ice Age, and a temperate climate epoch.