Earth Science involves the study of a single system and cannot progress through controlled experiments. There is no other planet earth to use as a control. This leads to the requirement that all observations be associated with a place and time – when and where were data collected.
For these data to form integrated pictures of Earth, the observations must be intercomparable over space and time. This requires that fixed measurement procedures are followed consistently and that instruments are calibrated by comparison to standards. Having measurement protocols and instrument specifications enables data from citizen scientists around the world, collected over years, to provide an coherent view of the environment and how it is changing. By comparing such data over space and time, patterns and trends are revealed, such as where are there deserts, savannahs, and forests and how are surface air temperatures changing.
Understanding the Earth system benefits from every well-made measurement provided it can be integrated with all the others by knowing when, where, and how it was taken.
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