  In recent months the figure of Greta Thunberg and the theme of climate
changings quickly became the focus of the debate. This has lead to a
polarization effect in opinion forming about the climate subject. Starting from
the analysis of this phenomenon, we develop an opinion dynamics model in which
several types of contrarians agents are considered. Each agent is supposed to
have an opinion on several topics related to each other, thus the opinions
being formed on these topics are also mutually dependent. The aim of the paper
is to investigate the indirect effects of contrarians agents on the collective
opinion about these topics. Several numerical tests are presented in order to
highlight the main features of the model.
