This video focuses on how ESA's new Earth Observation satellite Envisat, which was to be launched at the end of the month that this aired, will contribute to monitoring the atmosphere. The programme focuses on Envisat's SCHIAMACHY instrument, which will build on the atmosphere monitoring data provided by the GOME instrument on ERS-2, as well as on the GOMOS and MIPAS sensors. Envisat data will be be more accurate and will help scientists to further understand such phenomena as global warming and ozone depletion. The contribution of satellite data in helping ensure international treaties, such as Kyoto, is highlighted. Prof Paul Crutzen, Nobel Prize Winner in Chemistry, gives soundbites on SCHIAMACHY, the evolution of knowledge on the atmosphere and how satellites have superceded expectations. Prof Dr. John Burrows, University of Bremen, provides soundbites on GOME data, using satellites to determine the budget of human activity in the atmosphere and the role of Envisat in atmospheric studies.