Abstract

Since 1990, the Sun has been in the declining phase of the quasi-bicentennial variation in total solar irradiance (TSI). The decrease in the portion of TSI absorbed by the Earth since 1990 has remained uncompensated by the Earth's long-wave radiation into space at the previous high level because of the thermal inertia of the world's oceans. As a result, the Earth has, and will continue to have, a negative average annual energy balance and a long-term adverse thermal condition. The quasi-centennial epoch of the new Little Ice Age has started at the end 2015 after the maximum phase of solar cycle 24. The start of a solar grand minimum is anticipated in solar cycle 27 ± 1 in 2043 ± 11 and the beginning of phase of deep cooling in the new Little Ice Age in 2060 ± 11. The gradual weakening of the Gulf Stream leads to stronger cooling in the zone of its action in western Europe and the eastern parts of the United States and Canada. Quasi-bicentennial cyclic variations of TSI together with successive very important influences of the causal feedback effects are the main fundamental causes of corresponding alternations in climate variation from warming to the Little Ice Age.