Climate change is of great concern to all age groups but in particular to children. "Simple" climate models have been in place for a long time and can be used effectively with post-16 students. For younger children, modifications are required, and we describe in this paper the development and use of two such models. The first (the Granny Model) is a pictorial version of the model that has been used extensively with primary and early secondary school aged children (14 and younger). The second is an online version of the simple climate model that can be used without recourse to the underpinning mathematics and science but allows children to experiment with changing variables and how these changes affect the average surface temperature of the Earth.