Product service systems (PSS) are an example of a novel business model billed as having the potential to significantly reduce the environmental burdens of production and consumption processes. However, despite widespread interest in PSS, consensus regarding their actual environmental impacts, particularly with regard to salient issues such as global warming, is lacking. Hence this paper explores existing research to investigate the state of the art regarding the climatic impacts of PSS, alongside the set of factors that influence climatic impacts. The paper comprises a systematic review of peer-reviewed academic literature, quantifying the extent to which different types of PSS have the capacity to reduce greenhouse gas emissions across multiple product categories. Our study shows that significant reductions in climatic emissions are possible, but PSS are in many cases associated with more modest reductions and, in some cases, increased emissions. Further, we observe no clear differences in climatic impacts according to the type of PSS model that is deployed. Rather, differences in climatic impact are influenced by factors such as production and design alongside use-phase impacts and contextual factors such as transportation and the energy mix. The study argues that further research is needed to establish a more robust baseline upon which to draw conclusions regarding the sources of climatic impacts, and outlines fruitful ways for companies to tackle the complexities of climatic emissions that are beyond their control.