Earth System Physics (ESP) was established at ICTP in 1998. It's initial focus was research and training activities in the development and testing of limited area climate models and the refinement and verification of a simplified atmospheric general circulation model. The research of the group has contributed and continues to contribute extensively to the IPCC research on climate change. The activity now includes areas of solid earth geophysics, aerosols and chemistry and climate impacts modelling in addition to climate change and climate variability and predictability research.