25th European Research Course on Atmospheres (ERCA) school was organized from 11th January to 9th February 2017 by Universite Joseph Fourier and CNRS in Grenoble, France. ERCA is a high level international course on the Physics and Chemistry of atmospheres, the climate system and climate change, atmospheric pollution at different scales and the human dimensions of environmental changes. The course also covers the solar influences on Earth's atmosphere and climate. This year, altogether 35 students were selected from all around the world to participate in ERCA. Jaša Čalogović was invited to give students two lectures ("Solar variability influences on the climate and cosmic ray - cloud link" and "A critical look at cosmic ray - cloud link: Forbush decreases and cloud cover"). Aim of lectures was to present the influences of solar activity on climate and the possible mechanisms linking solar activity with climate. The cosmic - ray hypothesis was also presented in detail with aim to show several potential problems in present and past studies analyzing geophysical data using correlations.