Earth’s spheres: conceptual and definitional debates

Eduard Suess’s invention of the word ‘biosphere’ sparked a trend of coining sphere-words, which has since evolved into something of a craze. Some of these words, such as atmosphere and hydrosphere, are simply name tags for their respective Earth spheres. Others, such as geosphere, are also used mainly as names but they carry more than one meaning. However, many sphere-words, including pedosphere, biosphere, ecosphere, anthroposphere, sociosphere, and technosphere, are far more than just names, bearing as they do, weighty conceptual connotations that fuel considerable debate. At a time when Earth and life scientists are attempting to understand the workings of the planet as a whole by modelling the interaction of its component spheres, and when they are collaborating with sociologists, anthropologists, and members of other human sciences to tackle current environmental challenges, it seems an opportune moment to probe the origin and meaning of words for the Earth spheres they investigate. To be sure, Earth System modelling is helping understand changes resulting from the interaction of all the Earth’s spheres, including the anthroposphere, over various time and space scales, while multidisciplinary, interdisciplinary, and transdisciplinary research is helping to address such global problems as sustainable development, climate change, water supply, and biodiversity loss. An awareness of the origin, development, and disputed meanings of many sphere-words that these approaches employ should prove salutary for their multifarious practitioners.