When Communication Enables Catastrophe: Nuclear Risk and the Short Lifetimes of Technological Civilizations

The Fermi paradox may partly reflect technological self-destruction acting as a Great Filter during post-industrial development. Because the empirical record consists of a single civilization observed over an eighty-year nuclear age, the exercise reported here is best understood as a structured, historically anchored scenario analysis rather than a data-driven statistical estimate. We develop a time-varying hazard model to estimate civilizational survival under nuclear risk, using Earth's documented close calls as an illustrative case. A Bayesian survival-analysis framework with regime-switching hazards captures temporal non-stationarity between Cold War and post-Cold War periods and propagates parameter uncertainty. Under high-alert nuclear postures, estimated annual hazards range from roughly 0.1% to 2%, implying median survival times on the order of decades to millennia conditional on institutional configuration. These hazards plausibly exceed natural extinction risks but may decline substantially with improved governance and control systems. The results bound detectable civilizational longevity and offer conditional implications for existential-risk prioritization and SETI expectations under deep uncertainty.