Environmental migration is a form of migration which happens because the environment changes where people live. These changes can be sudden (such as floods, droughts, earthquakes or volcanic eruptions), or they can happen over longer periods of time. An example of changes that occur only slowly are those of desertification or the rise of the sea level.
Despite problems in formulating a uniform and clear-cut definition of environmental migration, such a concept has increased as an issue of concern in the 2000s as policy-makers, environmental and social scientists attempt to conceptualize the potential societal effects of climate change and general environmental degradation. "Unless it is assumed" in order to consider a person a climate refugee, nature or the environment could be considered the persecutor.