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10.9.2013 | Von:
Jochen Oltmer

Which Effects Do Global Environmental Changes Have for Migration Relations?

Ein Hirte läuft über ein trockenes Feld des Himayatsagar Reservoir, das zweite große Reservoir in Hyderabad, der Hauptstadt des südindischen Bundesstaat Andhra Pradesh am Dienstag, 3. Mai 2005. Beamte warnen davor, dass Hyderabad eine ernste Wasserknappheit droht, sollte es in den nächsten Wochen nicht regnen.Extreme drought in Hyderabad, India. (© AP)

Volume of environmental migration

It is indisputable that the extent of ecologically unstable regions is growing year after year due to salinization, erosion, flooding and pollution, and desertification, that is, the expansion of deserts [1]. Despite the reality of the problem and the many debates on the reach of global climate change, our knowledge is still relatively limited regarding the meaning environmental determinants have on migration movements and, conversely, the role of migration flows in global environmental changes. The differing assessments on the scope of environmentally determined global migration alone show this. At the beginning of the 21st century the United Nations High Commissioner for Refugees (UNHCR) estimated that 24 million people were forced to move due to growing environmental degradation. In contrast, the International Committee of the Red Cross estimates the number at 500 million. Most recent estimates by the German government’s scientific advisory board on "Global Environmental Changes" refer to 25 to 60 million people so far that have had to leave their region of origin because of climate change. The UN-Framework Convention on Climate Change (UNFCCC) predicts that this number will climb to 150 million by the year 2050 [2].

Lack of a standard definition of the term "environmental refugee"

The wide range of different estimates leads back to a lack of clarity in definition [3]. The use of the definition "environmental refugee" or "climate refugee" for the various forms of environmental migration rather obscures the complexity of the underlying causes and motivations to migrate because it does not evaluate environmental and other determining factors. The environmental strain on one’s place of origin is rarely the only cause for emigration, but generally works in cooperation with other economic, social, cultural and political factors.

Table 3: Selected Estimates and Projections on the Extent of Environmental Migration Worldwide
SourceEstimations on the number of "envrionmental refugees" at time of publicationProjections of the number of future "environmental refugees"
Source: Aufenvenne/Felgentreff [2013].
Global Humanitarian Forum 2009: The Anatomy of a Silent Crisis. Geneva, pp. 48-4926 million "climate refugees"72 million "climate refugees" by 2030
Environmental Justice Foundation (EJF) 2009: No Place Like Home. Where Next for Climate Refugees. London, p. 4200 million "environmental refugees", which 150 million are "climate refugees" by 2050
United Nations University - Institute for Environment and Human Security 2007: Control, Adapt or Flee. How To Face Environmental Migration? Bonn, pp.15-1810 million "environmental refugees"50 million "environmental refugees" by 2010
Friends of the Earth 2007: A Citizen´s Guide to Climate Refugees. Amsterdam, p. 8200 million "climate refugees" by 2050
Greenpeace 2007: Klimaflüchtlinge. Die verleugnete Katastrophe. Hamburg, pp. 1-2, 2720 million "climate refugees"150-200 million "climate refugees" in the course of the next 30 years
Nicholas Stern 2007: The Economics of Climate Change. The Stern Review. Cambridge, pp. 128-130 150-200 million "climate refugees" by 2050
Christian Aid 2007: Human Tide: The real Migration Crisis. London, p. 5-625 million "environmental refugees"50 million "environmental" and 250 million "climate" regufees by 2050; plus a possible 645 million more people displaced by development projects like dams
United Nations 2005: Millennium Ecosystem Assessment Report. Washington.20 million "environmental refugees"50 million "environmental refugees" by 2050
United Nations High Commissioner on Refugees (UNHCR) 2002: Environmental Migrants and Refugees. Refugees No.127. Geneva, p. 1224 million "environmental refugees"
International Federation of Red Cross and Red Crescent Societies: World Disaster Report 2001, Focus on recovery. Geneva, p.1125 million "environmental refugees"
WorldWatch Institute 1988: Environmental Refugees: A Yardstick of Habitability. Washington, p. 3810 million "environmental refugees"
United Nations Environmental Program (UNEP) 1985: Environmental Refugees. Nairobi, p. 830 million refugees, of which many are "environmental refugees"

Affected regions

Climate changes take effect immediately where areas are threatened because of rising sea levels due to flooding or salinization [4]. Climate research assumes that the sea level rose a total of 15 to 20 centimeters in the 20th century. Since the beginning of the 1990s, it has risen about 3 centimeters per decade. Current model calculations predict a rise of one meter by the year 2100 [5]. A large portion of the world population is distributed across the edges of the continents. Around two-thirds of all people currently live in zones that are within 100 kilometers from the ocean [6]. Of the 50 largest cities of the world, 30 are located on the ocean. In the Pacific, around 7 million people live on islands that are threatened by a rise in sea level, among which are the "Sinking Islands" such as the Maldives, the Marshall Islands, Palau and the Salmon Islands, among others. Low-lying regions on the Gulf of Bengal, which in the past have already been confronted year after year with extensive flooding, are likewise endangered. This is also the case, for example, for the coastal zone in Bangladesh, where the rise in sea level due to climate change can reach between 1.44 and 2.09 meters by 2050. This would result in a reduction of the residential area by 16 to 18 percent, in which 13 to 15 percent of the population lives. Against this backdrop, apart from movement within the country, emigration from Bangladesh to India could increase. India is already the most significant destination of migration from Bangladesh. India’s present efforts to secure the border to Bangladesh against migrants have thus far shown limited effectiveness, despite great effort and expense in the erection of a strongly secured fence stretching almost 3,500 kilometers [7]. For Egypt, estimates for 2050 show an increase in sea level between 1.01 and 1.44 meters which will result in a 15 to 19 percent loss of possible livable surface area and could affect 14 to 16 percent of the total population. The largest proportion of those affected may be able to relocate inside the county [8].

The rise in sea level leads not only to a loss in potential residential surface area, but also to a loss of farmland. This in turn has effects for food security. Many of the low-lying coastal regions of Asia are "granaries" of the world in so far as a large share of the global rice production is concentrated there, on which millions of people are directly or indirectly dependent. Estimates are that the rice supply of around 200 million people is immediately threatened by the rise in sea level.

Effects of environmental crises

Environmental crises usually worsen already precarious economic structures, so that the temporary or permanent emigration appears to offer an improvement in living conditions. They often also appear at the same time to be culture crises, and are often politically exploited or lead to political conflicts, which in turn causes migration. In regions where there is little political stability, weakly developed state problem-solving capacities, and economies prone to crisis and social unrest, environmental crises will only increase the vulnerability of the region. They could even act in this regard as a catalyst and initiate a collapse of an already unstable political, social and economic order. On the other hand, it can be that stable political, social and economic systems develop reaction patterns that raise expectations of a more or less conflict-free resolution of the effect of environmental crises [9].

Yet looking at environmental migration also raises the question of potential migration destinations and with that also of the areas that could profit from climate change. The increased weight of environmental determinants in global migration is not expected to lead to trans- or intercontinental mass migration. The long history of avoiding famines and migration reactions to "failed states" makes it clear that due to limited resources of many of those affected, the reactions to climate and environmental change will especially influence the local and regional migration movements in areas of the world particularly at risk. According to estimates by the German government’s scientific advisory board, "Global Environmental Changes", the rich "North" will, as a main contributor to climate change, likely be affected little or not at all by migration in the "Global South" due to environmental changes because the largest part of these movements will remain on a small-scale or occur as "South-South migration".

Political and legal treatment of environmental migrants

Various aid organizations call for an extension of the Geneva Convention on Refugees and the recognition of the effects of climate change as grounds for protection. This request has thus far been rejected because the various overlapping motives those persons affected have for migrating make environmental causes almost impossible to determine. Moreover, the expansion of the right to asylum leads to the strengthening of restrictive asylum policies of some states that wish to limit immigration opportunities [10]. The majority of those affected do not cross national borders anyway and thus are categorized under "internally displaced persons" (IDPs), a group of people who do not fall under the protection of the Geneva Convention on Refugees [11]. Until now only Sweden and Finland have created a legal framework in the context of environmental migration. In Finland those affected can receive humanitarian protection and receive a temporary residency permit e.g. in the case of an environmental catastrophe, whereas asylum or subsidiary protection is not granted.

This text is part of the policy brief on "Global Migration in the Future".


For a short overview: Latif (2010).
Wissenschaftlicher Beirat der Bundesregierung "Globale Umweltveränderungen" (2008); further estimates are summarized in Hummitzsch (2009); McLeman/Brown (2011, pp. 175-177).
White (2011, pp. 20f.).
Oliver-Smith (2011).
Rahmstorf/Schellnhuber (2012); Latif (2012).
Small/Nicholls (2003); McGranahan et al. (2008).
N.N. (2010, p. 411); Arnold (2012, pp. 217f.).
On Bangladesh and Egypt see Jacobson (1988, pp. 32-35).
Concerning this see e.g. McDowell/Morell (2010, pp. 117-136).
McAdam (2011, p. 56).
Guidelines on dealing with internally displaced persons: www.idpguidingprinciples.org
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