Survivalism is a commonly used term for the preparedness strategy and subculture of individuals or groups anticipating and making preparations for future possible disruptions in local, regional, national, or international social or political order. Survivalists often prepare for this anticipated disruption by learning skills (e.g., emergency medical training), stockpiling food and water, preparing for self-defense and self-sufficiency, and/or building structures that will help them to survive or "disappear" (e.g., a survival retreat or underground shelter). The specific preparations made by survivalists depend on the nature of the anticipated disruption(s), some of the most common scenarios being: The roots of the modern Survivalist movement in the United States and Britain can be traced to several sources, including government policies, threats of nuclear warfare, religious beliefs, writers warning of social or economic collapse, apocalyptic and post-apocalyptic fiction and climate change.