A Climate or Carbon Club has been proposed as a form of cooperation which could be established between like-minded countries sharing ambitious climate policies to encourage all others to follow suit and embark on equally grand climate measures. For the time being, this is a rather amorphous idea which needs to be converted into an effective instrument of the global climate transition. It remains unclear who could form a club, how its members could organise cooperation, what conditions would be expected from those willing to join, and what kind of instruments members could use to achieve their club’s aims. This In Brief seeks to shed some light on the concept.