The Sun experienced a period of very, perhaps exceptionally high activity during the 20th century, now called the Grand Modern Maximum (GMM). However, the relative height of the GMM with respect to the solar activity maxima in the previous centuries still remains under debate. Little is known yet about the causes of long-term solar activity variability in general, or on the detailed processes related to the evolution of solar magnetic fields during the GMM. However, it is known that the GMM has dramatically affected the condtions in the heliosphere, including the Earth.
This session gives a framework for studies on the many aspects of long-term solar activity (sunspots, TSI/SSI, coronal holes etc), especially to those related to the GMM, the different changes and phenomena taking place in the Sun over the GMM period, as well as their consequences in the heliosphere and in the near-Earth space. Effects of this variability to the Earth’s atmosphere and climate are also welcome, as well as studies of other grand maxima and minima, and considerations about the future of the solar-terrestrial environment after the GMM.