Not all environmental problems attract the same public attention. Some, such as sewage overflow into urban waterways, remain well out of the public eye while steadily increasing in severity. Others, notably the new global environmental problems such as biodiversity loss, global warming, ozone depletion and tropical deforestation, achieve international prominence despite conflicting scientific opinion. This work argues that society's willingness to recognize and solve environmental problems rests primarily upon the claims-making activities of a number of issue entrepreneurs in science, mass media and politics.