1143 Human Reconfguration of the Biosphere Mark Williams, Jan Zalasiewicz, and Julia Adeney Thomas Abstract The biosphere coevolves with the atmosphere, hydrosphere and litho- sphere to maintain a habitable space on Earth. Over billions of years – and despite periodic setbacks – it has evolved increasing complexity, from its microbial begin- nings to the complex interactions between animals, plants, fungi and unicellular microscopic life that sustain its present state. Recently, the biosphere has been pro- foundly changed by humans. In part, this includes increased rates of extinction that are reminiscent of past fundamental perturbations to life. But the change is even more profound, resulting from a combination of marked translocations of species beyond their indigenous ranges, overt concentration of biomass in humans and their farm animals, reconfguration of landscape habitats and over-utilisation of ocean life, excessive appropriation of energy from the biosphere (including its fossilised component), and increasing interconnectivity between technology and life. The biosphere is a fundamental component of the Earth System, existing for billions of years, and co-evolving with the atmosphere, lithosphere and hydrosphere to maintain a habitable space for life (Vernadsky, 1998). It is ubiquitous at the Earth’s surface, extending several kilometres into the lithosphere, where its subsurface mass alone is considered to be ≈15% of the total carbon in the biosphere (Bar-On et al., 2018). It also extends high into the atmosphere, where microbes are important for atmospheric processes such as cloud formation (e.g., DeLeon-Rodriguez et al., 2013). The total mass of carbon in the biosphere is of the order of ≈550 gigatons (Gt, a gigaton = one billion metric tonnes), with plants accounting for ≈450 Gt: by comparison, animals are ≈2 Gt. Before widespread deforestation by humans, the M. Williams (*) · J. Zalasiewicz University of Leicester, Leicester, UK e-mail: mri@le.ac.uk; jaz1@le.ac.uk J. A. Thomas University of Notre Dame, Notre Dame, IN, USA e-mail: jthomas2@nd.edu © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 N. Wallenhorst, C. Wulf (eds.), Handbook of the Anthropocene, https://doi.org/10.1007/978-3-031-25910-4_187