Non-Technical Summary. We are in a polycrisis – the entanglement of crises across multiple, interconnected global systems such as climate, health, and finance – that interact to produce harms significantly greater than the sum of their parts. We propose that, to mitigate and adapt to this polycrisis, strong systemic risk governance is required, and that just and effective governance requires principles. Principles help us to identify common values, provide a framework for decision-making, and lead the necessary societal change towards a shared vision, taking on increasing importance in an ever more complex and fragile world. Technical Summary. We are facing multiple crises, from risks across systems that are central to the safety and prosperity of humanity and ecosystems. Traditional planning and implementation have been based on command-and-control approaches with narrow objectives formulated within a constrained logic model. However, the polycrisis and addressing systemic risk require multiple objectives beyond narrow ones, which cannot address large-scale initiatives in complex, dynamic environments aimed at systems transformation. This requires a deep consideration of what objectives societies and organizations have and how they should meet them. The notion of utilizing a set of guiding principles is critical. Principles are becoming ever more prominent in considerations around the different ways in which societies, organizations, and individuals operate. Principles take on increasing importance in an ever more complex world where our effectiveness depends on adapting to context, guiding adaptation, and facilitating dialogue on options, trade-offs, and choices. We propose a set of 10 principles to guide the development of the field of systemic risk assessment and response within and across multiple domains. These principles – developed to meet the needs of the field of systemic risk – provide a complete set of operating guidelines to drive towards safety, equity, and security for human and ecological systems. Social Media Summary. This article proposes 10 principles for systemic risk governance to navigate the polycrisis and ensure a safe future.

Human societies and ecological systems face increasingly severe risks, stemming from crossing planetary boundaries, worsening inequality, rising geo-political tensions, and new technologies. In an interconnected world, these risks can exacerbate each-other, creating systemic risks, which must be thoroughly assessed and responded to. Recent years have seen the emergence of analytical frameworks designed specifically for, or applicable to, systemic risk assessment, adding to the multitude of tools and models for analysing and simulating different systems. By assessing two recent global food and energy systemic crises, we propose a methodological framework applicable to assessing systemic risks in a polycrisis context, drawing from and building on existing approaches. Our framework’s polycrisis-specific features include: exploring system architectures including their objectives and political economy; consideration of transformational responses away from risks; and cross-cutting practices including consideration of non-human life, trans-disciplinarity, and diversity, transparency and communication of uncertainty around data, evidence and methods.

The stability of the Greenland Ice Sheet under global warming is governed by a number of dynamic processes and interacting feedback mechanisms in the ice sheet, atmosphere and solid Earth. Here we study the long-term effects due to the interplay of the competing melt-elevation and glacial isostatic adjustment (GIA) feedbacks for different temperature step forcing experiments with a coupled ice-sheet and solid-Earth model. Our model results show that for warming levels above 2 C, Greenland could become essentially ice-free within several millennia, mainly as a result of surface melting and acceleration of ice flow. These ice losses are mitigated, however, in some cases with strong GIA feedback even promoting an incomplete recovery of the Greenland ice volume. We further explore the full-factorial parameter space determining the relative strengths of the two feedbacks: our findings suggest distinct dynamic regimes of the Greenland Ice Sheets on the route to destabilization under global warming - from incomplete recovery, via quasi-periodic oscillations in ice volume to ice-sheet collapse. In the incomplete recovery regime, the initial ice loss due to warming is essentially reversed within 50000years, and the ice volume stabilizes at 61-93 of the present-day volume. For certain combinations of temperature increase, atmospheric lapse rate and mantle viscosity, the interaction of the GIA feedback and the melt-elevation feedback leads to self-sustained, long-term oscillations in ice-sheet volume with oscillation periods between 74000 and over 300000 years and oscillation amplitudes between 15-70 of present-day ice volume. This oscillatory regime reveals a possible mode of internal climatic variability in the Earth system on timescales on the order of 100000years that may be excited by or synchronized with orbital forcing or interact with glacial cycles and other slow modes of variability. Our findings are not meant as scenario-based near-term projections of ice losses but rather providing insight into of the feedback loops governing the "deep future"and, thus, long-term resilience of the Greenland Ice Sheet.

Collective behavior provides a framework for understanding how the actions and properties of groups emerge from the way individuals generate and share information. In humans, information flows were initially shaped by natural selection yet are increasingly structured by emerging communication technologies. Our larger, more complex social networks now transfer high-fidelity information over vast distances at low cost. The digital age and the rise of social media have accelerated changes to our social systems, with poorly understood functional consequences. This gap in our knowledge represents a principal challenge to scientific progress, democracy, and actions to address global crises. We argue that the study of collective behavior must rise to a “crisis discipline” just as medicine, conservation, and climate science have, with a focus on providing actionable insight to policymakers and regulators for the stewardship of social systems.