Nuclear War

Current geopolitical instability—marked by escalating tensions among nuclear powers, dismantled arms control treaties, and proxy conflicts—has elevated the risk of large-scale nuclear exchange. A full-scale war involving the U.S., Russia, China, or regional powers like India and Pakistan could trigger nuclear winter, collapsing global agriculture and causing cascading societal collapse. Unlike slow-onset threats such as climate change, nuclear war offers no recovery window; its immediate and irreversible consequences could render large portions of Earth uninhabitable. The erosion of diplomatic safeguards and the proliferation of advanced delivery systems further heighten this existential risk above other plausible threats.