The Earth System Grid Federation (ESGF) is a globally distributed e-infrastructure for the hosting and dissemination of climate-related data. ESGF was originally developed to support the community in the analysis of CMIP5 (5th Coupled Model Intercomparison Project) data in support of the 5th Assessment report made by the IPCC (Intergovernmental Panel on Climate Change). Recognising the challenge of the large volumes of data concerned and the international nature of the work, a federated system was developed linking together a network of collaborating data providers around the world. This enables users to discover, download and access data through a single unified system such that they can seamlessly pull data from these multiple hosting centres via a common set of APIs. ESGF has grown to support over 16000 registered users and besides the CMIPs, supports a range of other projects such as the Energy Exascale Earth System Model, Obs4MIPS, CORDEX and the European Space Agency’s Climate Change Initiative Open Data Portal.