Cirrus clouds are an integral part of the climate system and play a key role in the Earth's energy budget. However, many aspects of the formation of cirrus and its wider impacts on the Earth system are not well understood. Some of the outstanding issues in this field were addressed at the Royal Meteorological Society meeting on Cirrus and the Earth System on 22 April 2015 at Imperial College London. The interdisciplinary event was organised and introduced by Marcus Köhler (University of Birmingham) and co‐organised by Anthony Baran (Met Office). Topics covered in the meeting, which was chaired by Rob MacKenzie (University of Birmingham), ranged from the development and application of new measurement techniques to observations and modelling of cirrus in global‐scale models