The individual can do a lot to save CO2. But what should we do? And when have we done "enough" personally? The philosopher Prof. Bernward Gesang comes to a conclusion that may be surprising for many: We should primarily donate. About 4% of our income and 1% of our time. Because donations are the most effective measure that individuals can contribute to climate protection. We took a closer look and talked to the philosopher, who teaches at the University of Mannheim, about his latest book, "Mit kühlem Kopf: Über den Nutzen der Philosophie für die Klimadebatte.