Assessing natural global catastrophic risks

Extinction of the human species: What could cause it and how likely is it to occur?

The possibility of human extinction has received growing academic attention over the last several decades. Research has analysed possible pathways to human extinction, as well as ethical considerations relating to human survival. Potential causes of human extinction can be loosely grouped into exogenous threats such as an asteroid impact and anthropogenic threats such as war or a catastrophic physics accident. In all cases, an outcome as extreme as human extinction would require events or developments that either have been of very low probability historically or are entirely unprecedented. This introduces deep uncertainty and methodological challenges to the study of the topic. This review provides an overview of potential human extinction causes considered plausible in the current academic literature, experts' judgements of likelihood where available and a synthesis of ethical and social debates relating to the study of human extinction.

The Fragile State of Industrial Agriculture: Estimating Crop Yield Reductions in a Global Catastrophic Infrastructure Loss Scenario

Modern civilization relies on a complex, globally interconnected industrial agriculture system to produce food. Its unprecedented yields hinge on external inputs like machinery, fertilizers, and pesticides, rendering it vulnerable to disruptions in production and international trade. Such a disruption could be caused by large-scale damage to the electrical grid. Solar storms, nuclear detonations in the upper atmosphere, pandemics, or cyber-attacks, could cause this severe damage to electrical infrastructure. To assess the impact of such a global catastrophic infrastructure loss on major food crops (corn, rice, soybean, wheat), we employ a generalized linear model. The predictions show a crop-specific yield reduction between 15% and 37% in phase 1, the year after the catastrophe, assuming rationed use of fertilizers, pesticides, and fuel stocks. In phase 2, when all stocks are depleted, yields decrease by 35%-48%. Soybean is less affected in phase 1, while all crops experience strong declines in phase 2. Europe, North and South America, and parts of India, China, and Indonesia face major yield reductions, potentially up to 75%, while most African countries are less affected. These findings underscore the necessity for preparation by highlighting the vulnerability of the food system.