Defining ‘environmental migration’

There is currently no consensus on definitions in this field of study. The resulting variety of terms is not just confusing but unhelpful.

Terms and concepts such as environmental migration, climate change-induced migration, ecological or environmental refugees, climate change migrants and environmentally-induced forced migrants are found scattered throughout the literature. The main reason for the lack of definition relating to migration caused by environmental degradation or change is linked to the difficulty of isolating environmental factors from other drivers of migration. Another major hindrance lies in the confusion of forced versus voluntary migration. Is environmental migration inherently a form of forced displacement? Can it take the form of voluntary relocation? What about government resettlement schemes in anticipation of or following an environmental disruption? Does the distinction between forced and voluntary matter? These questions impact on typologies of environmental migration and cannot be easily circumvented.

Aside from clear cases where sudden-onset environmental changes such as those resulting from earthquakes or floods lead to forced displacement, the problem is that environmental migration commonly presents itself where there is a slow-onset environmental change or degradation process (such as desertification) affecting people who are directly dependent on the environment for their livelihood and causing them livelihood stress. When environmental degradation is a contributing but not major factor, it becomes questionable whether such migration can be called environmental migration. The increased complexity of current migration patterns also contributes to the difficulty of finding a consensus over definitions.

Since the 1970s, a clear divide has existed between those forecasting waves of ‘environmental refugees’ and those adopting a more sceptical stance. Generally speaking, the former, who tend to isolate environmental factors as a major driving force of migration, can be described as ‘alarmists’ and the latter, who tend to insist on the complexity of the migration process, as ‘sceptics’. Interestingly, alarmists usually come from disciplines such as environmental, disaster and conflict studies, while sceptics belong almost exclusively to the field of forced migration and refugee studies. Unsurprisingly, reports linking climate change with security issues usually side with alarmists.

Just as most classical theories on migration tend to ignore the environment as a driver of migration, most theories on environmental governance ignore migration flows. Bridging this gap should be the first priority of a research agenda in this field.

Making progress

For academic purposes the interest in developing a definition lies in understanding the factors underlying migration decisions. While this is also of interest and concern to policymakers, they have an additional need to know what rights such a person is afforded. Without a precise definition, practitioners and policymakers are not easily able to establish plans and make targeted progress. Migrants and displaced persons falling within the definition are not clearly recognisable and may thus not receive appropriate assistance. In this sense, while much of the scholarly debate and policy recommendations to date have rightly cautioned against mixing those displaced by environmental causes with those defined as refugees by the 1951 Geneva Convention, there are many helpful elements of the process of defining someone under the Geneva Convention that can contribute to defining people displaced by environmental change.

With respect to the question of environmental migration, the focus to date has been on somehow proving that environmental factors can be a single major cause for displacement and migration. However, it is interesting to note that in determining whether or not someone is a ‘Convention refugee’ it is not necessary to determine whether or not the reason leading to persecution (political opinion, race, nationality, religion or membership of a particular social group) is the main reason for displacement but whether or not it happened. Once this link is established then the decision maker can grant the person refugee status without considering whether or not the reason was the main cause leading to the persecution. Could/should the same be done for people displaced by environmental factors? Is it enough to prove the causal relationship between environment and displacement or should the causal relationship result in a certain degree of hardship or breach of human rights before there can be some form of long-term international protection?


The need for a definition is a crucial step in the conceptualisation of environmental migration, and the development of policy responses to address these flows. However, two main factors driving the need for a definition could hinder its development.

Firstly, many scholars would like to establish environmental migration as a specific field within migration studies. There is a tendency to fence off this area and consider it apart from classical migration theories, as if environmental migration were of another kind. More would be gained by trying to integrate environmental factors into existing migration studies.

Secondly, there is a widespread appetite for numbers and forecasts amongst journalists and policymakers. In order to make their research policy-relevant, many feel compelled to provide some estimation of the number of those who are or may become ‘environmentally displaced’. These numbers, obviously, need to rely on a clear definition of who is an environmental migrant. Larger definitions draw bigger numbers; there is a tendency to enlarge the definition so as to encompass as many people as possible. However, defining environmental migration too widely would be damaging for those in need of the most protection.


Olivia Dun ( is a Research Associate at the United Nations University Institute for Environment and Human Security (UNU-EHS) ( in Bonn, Germany and a PhD Candidate of the University of Sydney, Australia ( François Gemenne ( is a FNRS Research Fellow at the Centre for Ethnic and Migration Studies of the University of Liege ( and at the Centre for International Studies and Research (CERI) of Sciences Po Paris ( Both are involved in the EU’s Environmental Change and Forced Migration Scenarios project (EACH-FOR

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