Lower magnitude volcanic eruptions as Global Catastrophic Risks

Large-magnitude volcanic eruptions have long been considered to pose a threat to the continued flourishing of humanity. The dominant narrative focuses on the nuclear-winter climatic scenarios that may develop as a result of a large-magnitude eruption (magnitudes 7+ on the Volcanic Explosivity Index (VEI)) propelling large quantities of ash and gas into our upper atmosphere and devastating global crop production. However, the probability of such an event remains rare, and this narrative fails to fully consider the vulnerability component of the risk equation. We propose that volcanic eruptions of even moderate magnitudes (VEI 3-6) could constitute a global catastrophic risk (events that might inflict damage to human welfare on a global scale) where the impacts of the eruption are amplified through cascading critical system failures.

Increased globalisation in our modern world has resulted in our overreliance on global critical system – networks and supply chains vital to the support and continued development of our societies (e.g. submarine cables, global shipping routes, transport and trade networks). We observe that many of these critical infrastructures and networks converge in regions where they could be exposed to moderate-scale volcanic eruptions (VEI 3-6). These regions of intersection, or pinch points, present localities where we have prioritised efficiency over resilience, and manufactured a new GCR landscape, presenting a scenario for global risk propagation. We present seven global pinch points, including the Strait of Malacca and the Mediterranean, which represent localities where disruption to any of these systems can result in a cascade of global disruptions. This is exemplified by the 2010 Eyjafjallajökull VEI 4 eruption which resulted in the closure of European airspace and cascaded to cause global disruption to just-in-time supply chains and transportation networks.

We suggest that volcanic risk assessments should incorporate interdisciplinary systems thinking in order to increase our resilience to volcanic GCRs.