I. Man-made - involves every hazard introduced into the general macro-system of the natural world that is a result of human actions. It includes things such as pollution (including accidents such as nuclear reactor meltdowns), wasteful behaviour, and deforestation.
- Depletion of natural resources
II. Natural – involves natural disasters that are not attributable towards human actions. They are a result of natural cycles.
- Biological (disease and epidemics)
III. Socioeconomic - involves problems that arise due to societal and economic shortcomings.