The Impact of Climate Change: Migration and Cities in South America

By Elizabeth Warn1, Susana B. Adamo2

Cities – particularly megacities – are becoming focal points for climate change impacts. Rapid urbanization, accelerating demand for housing, resource supplies and social and health services, place pressure on already stretched physical, social and regulatory infrastructure, heightening risks and vulnerability. In South America, internal migration flows – as well as immigration – are mostly to cities. Migrants, notably those of low socioeconomic status, are often particularly vulnerable as they are more likely to reside in areas at risk of environmental hazards. They are also likely to lack local knowledge, networks and assets, and are, therefore, less prepared to cope with, and avoid, the impacts of these hazards.

The impact of climate change and environmental degradation on migration and cities is not fully known. Sea level rise, land degradation and desertification, as well as changes in water availability, including glacial melt, are three important factors in the interplay of migration drivers and environmental change. Additional migration to cities is likely to exacerbate pre-existing vulnerabilities related to inequality, poverty, indigence and informality (informal work and settlements), and worsen the situation of those exposed to environmental risk factors. This places further stress on the ability of cities to adapt to climate change. At the same time, migration and other forms of mobility are common responses for coping with and adapting to environmental hardship, stress and risks. Migrants make important contributions to the cities that they live in, and migration to cities should, therefore, be appropriately managed and planned for.

Understanding the dynamics between migration and cities is an important priority of the International Organization for Migration (IOM). The Organization´s 2014 World Migration Report and upcoming Ministerial-level conference will be devoted to migrants and cities.3 This article highlights some of the recent processes linking population mobility, urban settlements and environmental change, including climate change in South America.

Cities and urban growth in South America

South America and the Caribbean is the most urbanized of the developing regions and one of the most urbanized in the world. In 2010, 83% of the population of South America resided in cities – it will be 86% by 2020. While the Southern cone has some of the lowest population densities in the world, a high proportion live in one or two very large cities per country.

More than 20% of the population of Latin America is concentrated in the largest city of each country. With total populations in excess of 10 million, Buenos Aires, Rio de Janeiro, Sao Paulo, and Belo Horizonte already count as megacities. While Bogota, Lima and Santiago are approaching the 10 million mark. These cities make up social, economic and, in many cases, political hubs, being home to a major share of urban dwellers in the region.

In the last decades, urban growth within South America has been less rapid in large cities and megacities than nticipated. Instead, growth is concentrating in mid-size or small cities and urban centres or in the margins of metropolitan regions. Cities are spreading out further and further over large metropolitan urban areas, across municipal, regional and even national borders.

Migration, immigrants and cities in South America

In terms of internal mobility, cities are important recipients of predominately urban-urban, rural-urban and intra-urban flows. There are also flows of urban-rural, seasonal and temporary migration, which remain difficult to quantify. Within the region, Chile and Colombia have some of the highest rates of lifetime internal migration intensity with far higher rates of internal compared to international migration.

Immigration flows are generally directed to major cities. In Argentina, Chile and Brazil, most immigrants are concentrated in large cities. In Argentina, 70% of migrants are thought to reside in the Metropolitan Area of Buenos Aires, in Chile 65% reside in the Metropolitan Area of Santiago, while the majority of those in Brazil live in São Paulo and, to a lesser extent, Rio de Janeiro and Paraná. Migration from lesser developed to more prominent cities has gained importance in recent years but is still vastly understudied. Recent international immigration in South America originates from within the region. Nevertheless, immigration remains a small percent of migration in the majority of the region. There are also important numbers of internally displaced persons due to conflict or natural hazards, predominately in Peru and Colombia. Urban displaced persons converge on capitals and megacities, but also on peri-urban areas and secondary cities, for example Santa Marta in Colombia.

Estimates of the number of immigrants in cities in South America remain imprecise primarily due to a lack of data,4 but also due to levels of irregularity. There are few studies that specifically assess the conditions of migrants vis-à-vis native-born populations. Migration is mainly driven by the search for better opportunities, including employment and higher salaries, but also by poverty in the areas of origin. Immigrants and migrants usually derive from lower ocioeconomic groups, experiencing greater levels of poverty, delayed social mobility and precarious social conditions.

Cities, in particular capitals, are perceived to be centres of economic growth and employment opportunities for migrants. Conflict and generalized violence drives migration in certain areas, from rural to urban areas and between and within urban areas. Environmental factors including land egradation and desertification may also play a role as a migration driver. For example, a significant proportion of the population of the landslide and flood susceptible favelas of Rio de Janeiro are migrants from the dryland areas in northeast Brazil.

 A favela on the outskirts of Salvador de Bahia, Brazil / © Scott Wallace, World Bank

The interrelationship between climate change, urban risk, migration and cities

Migration patterns are modified or exacerbated by climate events and trends rather than solely caused by them, making the impact of environmental or climate change dynamics hard to predict. Urban areas and cities are affected by slow-onset events, changes in water availability and the general scarcity of natural resources, which may also be linked with potential migration.

Low-level coastal zones will be affected by a rise in sea level, changes in rainfall regimes and the ocean chemistry. Degradation of coastal/marine ecosystems will affect areas that are considered among the most important in terms of urbanization and economic change. Sea level rise in South America is more likely to affect urban rather than rural dwellers – 77% of those considered to be in at risk areas live in cities. Small and medium-sized cities could become destinations for migration flows from larger cities as sea level rise and water scarcity hit large coastal metropolitan areas.

Access to, and use of water, is likely to be one of the greatest challenges to cities in South America. Greater urban growth implies increased water use in cities, and the possible need to divert water to these cities to meet demands. Glacier retreat and melt can exacerbate current water resources-related vulnerability, affecting water availability and impacting on large cities and urban settlements, notably La Paz, El Alto, Lima, Arequipa, and Quito.

Agricultural production in the outskirts of large cities and urban zones requires intensive water use. Diverting water to cities can undermine the viability of local agriculture, particularly in dry climates, which may also have migration implications. “In Bolivia, decreasing water availability [partially due to glacial melt] could lead to changing land use, an accelerated rate of depopulation and further migration towards cities”.5 Studies that have linked projected impacts of water availability on agriculture, and the corresponding economic impacts, suggest that full-scale migration could occur from Brazil´s northeast.

Cities: environmental hazards, vulnerability and heightened risks

The increase and intensity of sudden onset natural hazards such as droughts, extreme temperatures and heavy rains are likely to be the most immediate impacts of climate change on cities, linked with mobility. The urban population in South America is concentrated in areas of high vulnerability to environmental and climate hazards. Cities located in areas at high risks of droughts, earthquakes and loods, such as Quito and Santiago, are facing multiple hazards. Quito is also vulnerable to landslides and a volcano.

Examples of how environmental hazards have affected cities in South America are numerous, and are likely to increase as the impacts of climate change intensify and urban populations grow and concentrate. In Quito, during the winter of 2010, excessive rainfall contributed to a landslide in a marginal area, killing five people and forcing the relocation of at least 130 families. In Bogota, in 2011, rainfall was 300% higher than normal, triggering the evacuation of 711 buildings and the displacement of thousands. In Rio de Janeiro, in 2013, excessive rainfall caused flooding and mudslides in metropolitan areas.

Additionally, a large proportion of urban expansion is taking place in areas exposed to environmental hazards such as low-lying deltas and, low-lying plains, coastal zones, stepped slopes and drylands. There is an increasing concentration of population on potentially hazardous locations in coastal megacities, especially in informal ettlements. These areas are ill-suited to settlements as they are particularly prone to flooding and seasonal storms, and risks are amplified due to lack of essential infrastructure and services or inadequate provision for adaptation. For example, in Buenos Aires, informal settlements can be found in low-lying areas prone to flooding, while in Rio de Janeiro they are located on hilly areas prone to landslides and mudslides. 

The individuals that are most at risk from the likely impacts of climate change come from lower income groups. They face the greatest risks when environmental hazards occur, are less able to put into place short term measures to limit impacts, such as moving family members or assets, and least likely to be able cope with the impacts – health, injury, loss of property, etc – and to adapt – building better homes, disaster preparedness. Hazardous locations are more likely to lack infrastructure and services because they are not intended for settlement. Women, children, the health compromised, the elderly, those with disabilities and recent migrants are particularly vulnerable.

Cities located in areas at high risk of droughts, earthquakes and floods, such as Quito (above) and Santiago, are highly vulnerable to multiple climate hazards. / © Government of Equador

Migrants may face additional challenges, such as language barriers, lack of community participation, discrimination and prejudice, and difficulties in accessing health services, housing and land tenure as well as social protection mechanisms in the areas in which they reside. Internally displaced persons also face additional protection concerns. In Colombia, they were found to have lower labour outcomes, higher levels of unemployment and more limited access to financial capital and risk coverage than local communities.

Unlike locals, migrants and displaced persons may lack knowledge regarding previous disasters or environmental conditions and remain uninformed and unaware of risks, because of lack of exchange with local, better informed communities. Migrants from the northeast of Brazil living in Rio de Janeiro do not have personal experience with mudslides, which may account for their precarious building practices on slopes above the favelas.

Immigrants from South America are more likely to reside in informal settlements. Although figures are highly disputed, a considerable number of the inhabitants of informal settlements in Buenos Aires are believed to be immigrants, mainly from neighbouring countries.6 Cities with large informal settlements are likely to face challenges in protecting incoming populations, resulting in the paradoxical situation of populations migrating into more vulnerable areas as far as climate change effects are considered.

Recommendations to harness the positive impact of migrants’ contribution to cities and to adaptation

Despite their vulnerability, migrants play a significant economic, social and cultural contribution to the countries and cities in which they reside. They provide skilled and unskilled labour and create new enterprises. They also contribute to their communities of origin through transfer of remittances.

The measures suggested below could reduce the vulnerability and impact of hazards, and increase the adaptive capacities of migrants:

  1. Generate further data, studies and information regarding the complex interlink between cities, migration and the environment, including climate change
  2. There is a need to address gaps in scientific and empirical knowledge to better understand the level of vulnerability of cities to weather variability and climate change in order to build resilience to environmental hazards and implement adaptation strategies. While regional and national data may exist, comparable measurements at the local level do not. More research is also required to address certain gaps in the understanding of the impact of environmental change on cities in particular in relation to migrants and other vulnerable groups. The implication of climate change, exposure and vulnerability on health and migrants is a particular area that warrants further research.
  3. Develop and strengthen policy measures, legislation and infrastructure at the municipal level to increase the adaptive response of migrants and cities
  4. Further measures are required to address irregularity and inequality between migrants and non-migrants through social inclusion and promotion of human rights. Several countries in South America have introduced changes to the domestic legislation on migration towards facilitating entry and residence of citizens from within the region, thus reducing irregularity. The recent Brazilian initiative for the creation of a Municipal Coordination Office for Migrant Policies7 is an important step toward addressing the vulnerabilities of migrants at the city level. Legislative provisions that facilitate migrants´ community participation at the municipal level8 could also be used to develop migrants´ adaptive capacity through building local knowledge. For example, awareness of risk factors, improved local environmental knowledge and an understanding of slope dynamics might cause Brazilian favela dwellers to reconsider where they settle. In recent years, Bogotá, Buenos Aires, Esmeraldas, Quito, and São Paulo have adopted metropolitan level adaptation plans. Such plans could also be developed to factor migration and particularly recent migrants as part of these cities adaptive response.
  5. Increase the capacity and knowledge of migrants to contribute to adaptation and to mitigate hazards in origin areas
    Migrants can also reduce their vulnerability and contribute to adaption by creating new livelihood opportunities and diversifying income streams. Knowledge and understanding will permit them to mitigate hazards in the places they have moved to as well as in those that they left behind. In the suburbs of Buenos Aires, migrants from Peru have savings groups that contribute funds to help recovery in areas back home hit by disaster.

Strengthening of infrastructure and policies

As the vector of economic growth and employment creation in many cities, migrants can act as a powerful source of innovation, income generation and experience that an be harnessed to reduce the impact of hazards and foster adaptation. South America will continue to be affected by humanitarian disasters intensified by climate change, such as intense rainfall, flooding, drought and hailstorms, with stressors becoming more pronounced due to the effects of population growth and redistribution, especially where infrastructure and regulations require further strengthening.

Residents of Amauta-B shantytown in Peru band together to build a restraining wall / © Scott Wallace, World Bank

Cities and urban areas in South America will require complex policy and operational responses to address the effects of climate change and to include migration into national and local development plans, adaptation planning and disaster risk reduction. In certain circumstances, institutional frameworks to ensure clearly defined competencies between local and national government may also be required.

A number of cities already have in place disaster risk reduction mechanisms for fast onset disasters. Greater coordination between sectorial policy and operational responses; improving land security and tenure, human security, access to housing, education, as well as portable social protection health, social services, will contribute to reducing the impact of environmental hazards and pave the way for factoring migration into responses to climate change. These responses will need to include increased city planning that is more responsive to migration-led growth and analysis of urban developments in the context of social and health impacts of climate change. In short, “Facing a new climate system and, in particular, the exacerbation of extreme events, will call for new ways to manage human and natural systems for achieving sustainable development” (IPCC, 2014).


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1 Senior Regional Specialist in Migration and Development for South America, International Organization for Migration (IOM)

2 Associate Research Scientist at CIESIN (Center for International earth Science Information Network), Co-coordinator of PERN (Population- Environment Research Network) and Adjunct Assistant Professor at Columbia University. This article draws on her presentation “Migration, cities and climate change in Latin America” for the Hamburg Conference Actions for the Climate-Induced Migration, Hamburg, 16-18 July 2013 jul2013.pdf. Ms Adamo is also a member of ALAP (Latin American Association for Population). In 2015 IOM and ALAP will organize a joint workshop for academics on Migration, Environment, Climate Change and Development.

3 Forthcoming in 2014.

4 Data regarding foreign-born individuals are scarce, and are normally taken from census data, and at times from household surveys, both sources which have their limitations.

5 Hoffmann, D. (2008) Consecuencias del Retroceso Glaciar En La Cordillera Boliviana. Pirineos, 163, 77-84

6 In Buenos Aires, migrants from Bolivia, Paraguay and Peru tend to concentrate in areas where the access to housing is cheaper and where living conditions are comparatively worse. They cluster in the south and southwest (where large informal settlements are located) and to lesser extent in the center-south of the city. In all the informal settlements, migrants from these countries are over-represented. For example, in the Villa 31 (Retiro), they represent 11.3% of the population.

7 In Brazil in May 2013, the Secretary for Human Rights and Citizenship of the city announced the creation of a Municipal Coordination Office for Migrant Policies. Addressing migration at the Municipal level is extremely new.

8 In Argentina in 2010, the National Government approved a Decree regulating the Migration Act of 2003. Under this new legislation, municipalities are obliged to create spaces for migrant participation, consultation, information and counselling and for channelling proposals and demands to the authorities. At State level, in 2001 the Brazilian State Parliamentary Council for Root Communities and Foreign Cultures was established by Bureau of the Legislative Assembly of the State of São Paulo (Resolution Nº 817, of 22 of November) with the objective of supporting the social integration of the various communities of foreign descent living in the State of São Paulo.

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