Current scientific studies of global change, based on existing data sets and models, have shown that human activities have an enormous potential for producing climatic and biological consequences. Unfortunately, given the observational limitations researchers now face, even the most comprehensive models produce results with large uncertainties that prevent the accurate prediction of Earth system changes due to human activities and natural variations. Scientists need long-term, consistent measurements of the key physical variables to advance the understanding of Earth system processes and improve model predictions. The EOS Program is based on 24 measurement categories that include the highest priority observations needed for studying each of the Earth system componentsΓÇôthe atmosphere, the land, the oceans, the cryosphere, and the solar radiative driving forceΓÇôand the interactions between these components.
