2016, Steffen, Will, Leinfelder, Reinhold, Zalasiewicz, Jan, Waters, Colin N., Williams, Mark, Summerhayes, Colin, Barnosky, Anthony D., Cearreta, Alejandro, Crutzen, Paul, Edgeworth, Matt, Ellis, Erle C., Fairchild, Ian J., Galuszka, Agnieszka, Grinevald, Jacques, Haywood, Alan, do Sul, Juliana Ivar, Jeandel, Catherine, McNeill, J.R., Odada, Eric, Oreskes, Naomi, Revkin, Andrew, deB. Richter, Daniel, Syvitski, James, Vidas, Davor, Wagreich, Michael, Wing, Scott L., Wolfe, Alexander P., Schellnhuber, H.J.

Stratigraphy provides insights into the evolution and dynamics of the Earth System over its long history. With recent developments in Earth System science, changes in Earth System dynamics can now be observed directly and projected into the near future. An integration of the two approaches provides powerful insights into the nature and significance of contemporary changes to Earth. From both perspectives, the Earth has been pushed out of the Holocene Epoch by human activities, with the mid‐20th century a strong candidate for the start date of the Anthropocene, the proposed new epoch in Earth history. Here we explore two contrasting scenarios for the future of the Anthropocene, recognizing that the Earth System has already undergone a substantial transition away from the Holocene state. A rapid shift of societies toward the UN Sustainable Development Goals could stabilize the Earth System in a state with more intense interglacial conditions than in the late Quaternary climate regime and with little further biospheric change. In contrast, a continuation of the present Anthropocene trajectory of growing human pressures will likely lead to biotic impoverishment and a much warmer climate with a significant loss of polar ice.

2020, Zipper, Samuel C., Jaramillo, Fernando, Wang‐Erlandsson, Lan, Cornell, Sarah E., Gleeson, Tom, Porkka, Miina, Häyhä, Tiina, Crépin, Anne‐Sophie, Fetzer, Ingo, Gerten, Dieter, Hoff, Holger, Matthews, Nathanial, Ricaurte‐Villota, Constanza, Kummu, Matti, Wada, Yoshihide, Gordon, Line

The planetary boundaries framework defines the “safe operating space for humanity” represented by nine global processes that can destabilize the Earth System if perturbed. The water planetary boundary attempts to provide a global limit to anthropogenic water cycle modifications, but it has been challenging to translate and apply it to the regional and local scales at which water problems and management typically occur. We develop a cross-scale approach by which the water planetary boundary could guide sustainable water management and governance at subglobal contexts defined by physical features (e.g., watershed or aquifer), political borders (e.g., city, nation, or group of nations), or commercial entities (e.g., corporation, trade group, or financial institution). The application of the water planetary boundary at these subglobal contexts occurs via two approaches: (i) calculating fair shares, in which local water cycle modifications are compared to that context's allocation of the global safe operating space, taking into account biophysical, socioeconomic, and ethical considerations; and (ii) defining a local safe operating space, in which interactions between water stores and Earth System components are used to define local boundaries required for sustaining the local water system in stable conditions, which we demonstrate with a case study of the Cienaga Grande de Santa Marta wetlands in Colombia. By harmonizing these two approaches, the water planetary boundary can ensure that water cycle modifications remain within both local and global boundaries and complement existing water management and governance approaches. © 2020 The Authors.

2020, Donges, Jonathan F., Heitzig, Jobst, Barfuss, Wolfram, Wiedermann, Marc, Kassel, Johannes A., Kittel, Tim, Kolb, Jakob J., Kolster, Till, Müller-Hansen, Finn, Otto, Ilona M., Zimmerer, Kilian B., Lucht, Wolfgang

Analysis of Earth system dynamics in the Anthropocene requires explicitly taking into account the increasing magnitude of processes operating in human societies, their cultures, economies and technosphere and their growing feedback entanglement with those in the physical, chemical and biological systems of the planet. However, current state-of-the-art Earth system models do not represent dynamic human societies and their feedback interactions with the biogeophysical Earth system and macroeconomic integrated assessment models typically do so only with limited scope. This paper (i) proposes design principles for constructing world-Earth models (WEMs) for Earth system analysis of the Anthropocene, i.e., models of social (world)-ecological (Earth) coevolution on up to planetary scales, and (ii) presents the copan:CORE open simulation modeling framework for developing, composing and analyzing such WEMs based on the proposed principles. The framework provides a modular structure to flexibly construct and study WEMs. These can contain biophysical (e.g., carbon cycle dynamics), socio-metabolic or economic (e.g., economic growth or energy system changes), and sociocultural processes (e.g., voting on climate policies or changing social norms) and their feedback interactions, and they are based on elementary entity types, e.g., grid cells and social systems. Thereby, copan:CORE enables the epistemic flexibility needed for contributions towards Earth system analysis of the Anthropocene given the large diversity of competing theories and methodologies used for describing socio-metabolic or economic and sociocultural processes in the Earth system by various fields and schools of thought. To illustrate the capabilities of the framework, we present an exemplary and highly stylized WEM implemented in copan:CORE that illustrates how endogenizing sociocultural processes and feedbacks such as voting on climate policies based on socially learned environmental awareness could fundamentally change macroscopic model outcomes. © Author(s) 2020.