The COP26 UN climate change summit that brings together most of the world’s leaders in Scotland this month should represent the end of rhetoric and the beginning of strong and effective action. The summit, one of the most consequential climate events since the negotiation of the Paris Agreement in 2015, aims to “build a more sustainable, resilient and zero-carbon future”. However, it will not be easy for the COP26 to represent a major breakthrough for the planet, because two of the most polluting powers in the world, China and Russia, are not participating. And because part of the world’s population no longer gives any credibility to governments that have been making empty promises for too many years, but have not been able to reduce global warming at all. The young Swedish activist Greta Thunberg, who has become an international reference point for the generation most sensitive to the negative effects of climate change, defined the failure of states in a very graphic way when she accused them of achieving nothing more than “blah, blah, blah”. Scientific evidence is accumulating and the trends threatening the planet are accelerating, but none of the commitments made so far have been of much use. The short-term prospects are already worrying, and real catastrophes are looming and about to threaten our way of life as we know it if big changes do not happen before it’s too late. Either we implement radical change now, or future generations will be the innocent victims of our abuses, excesses and mistakes. That is why there is growing concern among the young, because they see their future seriously threatened by behaviours for which they are not responsible. We will soon see whether a new list of the usual promises and declarations emerges from the Glasgow summit, or it becomes known as the moment when the world stopped all the “blah, blah, blah” and finally started to act decisively.