Advertising is tied to global warming through an endogenous growth model. The model allows for the possibility that the environment can become a source rather than a sink for greenhouse gases. Optimal control analysis of the model shows that a feasible steady state is possible for which the environment remains a sink, and identifies a sufficient condition for such to be the case. Comparative-static analysis shows that, for sufficiently small values of steady-state anthropogenic greenhouse gas concentration, global surface temperature and advertising in steady state are negative functions of parameters that measure the damaging effects of global warming.