Analysis of the sun's varying activity in the last two millennia indicates that contrary to the IPCC's speculation about man-made global warming as high as 5.8°C within the next hundred years, a long
period of cool climate with its coldest phase around 2030 is to be expected. It is shown that minima in the secular Gleissberg cycle of solar activity, coinciding with periods of cool climate on Earth,
are consistently linked to an 83-year cycle in the change of the rotary force driving the sun's oscillatory motion about the centre of mass of the solar system. As the future course of this cycle and its
amplitudes can be computed, it can be seen that the Gleissberg minimum around 2030 and another one around 2200 will be of the Maunder minimum type accompanied by severe cooling on Earth. This forecast should
prove 'skilful' as other long-range forecasts of climate phenomena, based on cycles in the sun's orbital motion, have turned out correct, as for instance the prediction of the last three El Niños
years before the respective event.