Global catastrophe scenarios

Scenarios in which a global catastrophic risk creates harm have been widely discussed. Some sources of catastrophic risk are anthropogenic (caused by humans), such as global warming, environmental degradation, and nuclear war. Others are non-anthropogenic or natural, such as meteor impacts or supervolcanoes. The impact of these scenarios can vary widely, depending on the cause and the severity of the event, ranging from temporary economic disruption to human extinction. Many societal collapses have already happened throughout human history.