The past decades have been characterized by a growing number of nonstate actors (NSAs) involved in global governance. However, despite this growth, only a small number of NSAs have been able to maintain a prolonged global presence over a substantial period of time. To explain why some NSAs are more active, we rely on resource dependence theory. We demonstrate that sustained advocacy over time can be explained by a density dependence mechanism, namely the more NSAs mobilize, the lower the chance that individual NSAs will prolong their global advocacy efforts. Analysis of data stemming from a unique data set of 5,627 NSAs active at the global climate conferences demonstrates that much advocacy in this field is indeed of an incidental nature, namely a large number of groups attend once and never return.