In this conversation, Nobel Prize winner Mario J. Molina reflects on the ethical side of science. He explains how several decades ago, together with the scientist F. Sherwood Rowland, he predicted that human activity was endangering the ozone layer. They discovered the mechanisms which could bring about the destruction of the layer due to the continuous release of industrial compounds, such as the so-called chlorofluorocarbons (CFCs), into the atmosphere. Professor Molina relates how the issue with the ozone layer was the first example of a problem on a truly global scale for science and, as such, had to be tackled, because without the ozone layer, life on our planet would not have evolved as we know it. Education and training are proving a great help with how the present challenge of stopping or mitigating the daunting problem of global warming should be approached. In the dialogue, different courses of action for persuading both decision-makers and the public are proposed. It is however proving rather difficult to achieve and something which, according to Professor Molina, is also related to education.