Understanding the dynamics of the Earth surface system in response to ongoing changes in the global environment is a major scientific challenge.
The development and calibration of models that predict how soil formation and degradation rates, surface hydrology, weathering reactions, export of organic carbon in rivers, and landscapes will respond to forcing in the next centuries, relies crucially on long term observations and times series measurements of chemical, physical, organic parameters. We invite contributions on chemical and physical monitoring, and modelling of geochemical, pedogenic, surface and groundwater hydrological, geomorphic, meteorological and biological processes in the "critical zone". We hope to highlight strategic activities in different settings and observatories, undertaken by diverse communities ranging from geomorphology and soil sciences, through geochemistry to meteorology.