Soils are complex ecosystems intrinsically interwoven with the surrounding environment. Local conditions such as topography, geomorphology, drainage, parent material, and microclimate are well-established drivers of soil formation, development, and function. Contemporary climate change constitutes a major global threat to soil functionality, although climatic variability has influenced pedogenesis throughout Earth history. Over millennia, and increasingly since the advent of mechanized agriculture and the widespread use of synthetic fertilizers and pesticides, agricultural intensification has become a dominant force shaping soil ecosystem processes. These transformations have degraded ecosystem integrity and functioning in many regions; within the European Union, an estimated 60–70% of soils are considered to be in poor health.
This article argues that understanding soil function and defining soil health must begin from two complementary perspectives: first, recognizing the hierarchical organization of patterns and processes operating both within soils and in relation to the broader environment; and second, applying a thermodynamic framework. The spatial scales relevant for soil ecosystem analysis span more than 50 orders of magnitude, from elementary particles to the observable universe, while temporal scales range from instantaneous radiation–matter interactions to the persistence of Precambrian paleosols. Across these spatial and temporal dimensions, soils have evolved through Darwinian selection favoring thermodynamically efficient dissipative systems capable of building internal organization while converting, regulating, and redirecting external energy and matter flows into negentropy. To improve the understanding, management, and optimization of soil health and ecosystem services, this article presents a conceptual framework linking soil functions to the spatial and temporal scales at which soils operate, together with the observational approaches required to assess relevant indicators across these scales.