**2. Material and methods**

Except for Introduction, Discussion and Conclusions, this is a review paper based on relevant scientific literature, as well as a number of books and articles which illustrate the debate about sustainability. The review part has been structured into four topics:

*Development of concepts.* Here, the gradual refinement of the sustainability concept has been summarized. Since its "foggy" presentation in 1987 [1], the concept has been vividly discussed, and a number of new concepts have evolved in order to analyse and implement it. We shall also study the rise of applied ecological thinking, how global warming has triggered new concepts, and the difficulty of expressing the value of nature as a source of life quality.

*Development of attitudes.* While concepts can be adopted, attitudes have to be personally developed. The process of developing attitudes is exemplified.

*Rhetoric matters.* Here, selected citations are presented to illustrate the power of language.

*Our ability to deny or suppress environmental threats.* This is a summing up from Jared Diamond's book "Collapse – How societies choose to fail or succeed" [2].

In the Discussion, we are reminded that concepts, attitudes and rhetoric must have the necessary quality. In debates, we must be ready to argue against misuse of concepts, unsus‐ tainable attitudes, "greenwashing" of unsustainable activity, and a "counter-rhetoric" which defends "business as usual".
