SAFETY & SECURITY | COVER STORY


Systemic risk and polycrisis


The potential for novel risks to impact the nuclear industry both now and in the future is significant. What actions might the industry need to take to further understand the risks and develop appropriate responses?


By Nick King, Principal Environmental Consultant, AtkinsRéalis Nuclear


Below: Systemic risks could apply through a large range of direct and indirect vectors operating at different scales. Source: WHO


OVER RECENT DECADES HUMAN societies at global scale have been increasingly characterised by ever-greater size, interconnectedness and complexity. This ‘direction of travel’ for the world is commonly described positively in terms of technological gains, economic growth and general progress, but an alternative and more cautionary perspective recognises that it may also introduce risk. This is because increasing rates of change and interconnectedness, along with growing and evolving hazards, stressors and threats of different types, are driving a generalised increase in ‘systemic risk’. Systemic risks are defined as those which may arise


from the unique features and behaviours characteristic of ‘complex systems’. These types of systems differ from simple and complicated systems in that they comprise very large numbers of deeply networked actors or ‘nodes’ (for example people, companies, species) which interact through phenomena such as feedback loops and emergence, and produce characteristic nonlinear, dynamic and unpredictable behaviours and outputs. Complex systems are widely distributed in both natural and human contexts, such as the climate system and ecosystems, and the internet and the global economy. They in turn drive a range of phenomena we are familiar with in everyday life such as the weather and the viral spread of ‘memes’. Any disruptions to a given complex system that affect the function and operation of that system may be described as


28 | February 2026 | www.neimagazine.com


a ‘crisis’. The capacity and tendency for crises to grow and spread within and/or between different systems is central to ‘systemic risk’. Where crises may interact in time and space to generate rapidly escalating and cascading effects greater than their contributing parts , this may be labelled as a ‘polycrisis’. This concept, which has seen increasing use in recent years, has no singular definition but the specialist research body The Cascade Institute (based at Royal Roads University) suggests: “A global polycrisis occurs when crises in multiple global systems become causally entangled in ways that significantly degrade humanity’s prospects. These interacting crises produce harms greater than the sum of those the crises would produce in isolation, were their host systems not so deeply interconnected” Systemic risk and polycrisis differ in that the former describes the potential for crises to occur, and the latter the realisation of that risk. Polycrisis also describes the tendency for disruptions to ‘spill over’ within and between systems. which ‘activates’ the properties of systemic risk and generates characteristic escalatory and spreading effects. Where this occurs, a crisis may cause cascading ‘layers’ of first, second and nth order effects. Taking the example of human greenhouse gas emissions, increasing storm frequency/intensity in a given region may be the first order effect of these accumulated emissions; the resultant damage to infrastructure the second order effect; the breakdown of supply chains from this damage the third; and all other consequent societal disruptions – such as shortages of goods – the nth order effects. Modern complex societies have become wholly reliant on multiple extensively interlinked systems. Examples include energy, food/agriculture, water, finance, and their interlinking supply chains. Such systems acquire, process, distribute and make use of stocks and flows of essential commodities, materials and data to keep everything continuously operational. These key supporting systems have become increasingly densely interconnected and interdependent in the characteristic manner of complex systems. They therefore foster the ideal conditions for the development of systemic risk and therefore crises and nth order impacts, which could potentially evolve into a polycrisis if disruptions become ‘runaway’. The range of potential hazards sources (or vectors) which may cause crises and drive systemic risk in the contemporary world is very large. These may be biophysical/natural phenomena or socio-economic and/or technological in nature and may occur at different scales of time and space. Some of the key hazard vectors in the


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