Tacoli, C.: Migration, climate change and the multiple drivers of mobility, 2012

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What we know (and what we don’t know) about the links between migration and climate change

For many years, there have been polarised views on the impacts of climate change on population movements. For some, climate change would result in hundreds of people moving away from their home areas and making their way from worst affected poor countries in the Global South to rich industrialised nations. This view has been disputed on the basis that it is based on a simplified view of migration that assumes that migrants are all the same and respond in the same way to emergency situations.

But perhaps the most important difference is that between those who view migration as a failure to adapt to environmental change (and therefore resulting in masses of migrants), and those who see migration as a key adaptive response to environmental, but also socio-economic, cultural and political change (and thus resulting in a complex range of migration flows with differences in terms of destinations, duration and composition)

There is now a broad consensus on the fact that climate change will result in increases in the numbers of people who move – but only as a contributing factor in the context of socio-economic and political transformations. There is also a better understanding of the need to consider the differences between displacement, voluntary (economic) mobility and distress migration.

Displacement is in many cases the result of extreme weather events such as typhoons and floods which force people to leave their homes. One of the impacts of climate change is the increase in the number and intensity of these extreme events.  Displacement is not necessarily a permanent move, however: whether people are able to return and reconstruct their homes within the same area depends largely on the support they get from local and national institutions, both governmental and non-governmental.

Voluntary migration needs to be distinguished from distress migration – the latter is more frequent in areas affected by both environmental change and conflict (which implies a lack of functioning local institutions). Voluntary migration, on the other hand, is an economic strategy increasingly used by rural and urban residents to diversify their income sources and reduce their vulnerability. It is thus a key adaptation strategy that responds to both environmental change and other transformations. What is important about voluntary migration is that it is extremely diverse, and includes seasonal movements between rural areas, temporary movements between rural areas and towns and between towns, and long-term movements to cities and across borders. Different durations and destinations also involve different socio-economic groups, with poor rural residents more likely to move between rural destinations where they can work as agricultural labourers, and wealthier and better educated groups, on the other end of the spectrum, more likely to move to urban centres where there are more employment opportunities.

The broader picture: urbanization, climate change and policy-makers’ perceptions of rural-urban migration

It is important to situate migration and climate change-related migration in the wider context of rapid urbanization. In the next 40 years, the world’s population is projected to increase by about 2.3 billion. Virtually all these people will live in cities and towns in Asia and Africa, reflecting relatively high levels of fertility as well as rural-urban migration driven by economic growth and the transformation of economies, from agriculture to industry and services.

Many of the rapidly growing urban centres that will absorb the world’s growing population are located in areas at risk – for example low elevation coastal zones susceptible to sea level rise. It is currently estimated that at least 900 million people live in ‘slums’ , and since these are located in the same rapidly growing cities in Africa and Asia, their numbers are also likely to rise.  Slums and informal settlements are disproportionately exposed to flooding and landslides, and often lack basic infrastructure such as water and sanitation. This increases risks for their residents, and are exacerbated by the impacts of climate change.

Most policy-makers have a negative view of rural-urban migrants, often on the assumption that they hold responsibility for the growth of urban poverty. However, migration is not the main reason for the growth of urban populations: natural population growth (the numbers of excess births over deaths) is the main reason for it. There is also another important reason why rural-urban migrants should not be penalised: urban centres, especially when they are relatively densely built, offer many more opportunities for the sustainable use of natural resources and better provision of basic infrastructure and services than dispersed rural settlements and populations. Despite this, a growing proportion of nations undergoing processes of rapid urbanization have policies that try and stop rural-urban migrants. These policies miss the point: they do not reduce urban growth, are likely to contribute to urban poverty by limiting migrants’ access to services and housing, and divert attention from what is instead really necessary – better capacity, resources and accountability for local governments.

Transformations in agriculture and access to natural resources

Changes in agricultural production systems and in access to natural resources, especially land and water, also have an important impact on how people respond to climate change, and whether such responses include migration. Climate change does affect farmers through desertification and increasingly irregular rainfall patterns. But access to land is also affected by the growing appropriation of land by large investors, frequently foreign, in what are often called ‘land grabs’. These are in many cases driven by the growing production of biofuels and biomass as alternative sources of energy that contribute to mitigation efforts, but which in many cases reduce the availability of land to smallholders and to pastoralists.

Access to water by these groups can also be reduced by the construction of infrastructure related to mitigation, such as the construction of hydroelectric dams, and to adaptation to climate change, such as the construction of water reservoirs and infrastructure to protect against floods and sea level rise and storm surges.

But in many cases the key factor that compels people to move elsewhere is the lack of alternative local sources of income-generation and employment. For the poorest and least skilled farmers, seasonal movement to areas with irrigated agriculture provides opportunities for waged agricultural labour. For better educated people, or those who can count on the support of relatives and friends, towns and cities provide employment opportunities in construction, domestic service and small-scale trade.

Mobility linked to the diversification of income sources has long been recognised as a key strategy of the rural and urban poor to make ends meet and, in some cases, move out of poverty.  As the impacts of climate change will increase the need to engage in seasonal migration and non-farm work, it is ever more important for policy-makers to support migrants rather than attempt to stop them from moving.

Migration as adaptation: poverty, vulnerability and the use of remittances

Recent research in environmentally fragile areas of Bolivia, Senegal and Tanzania shows that migration and short-term mobility are becoming essential elements of the livelihoods of poor and less poor people alike. In all three countries, environmental change has been particularly harsh in the past two decades. In all three countries, however, it is the combination of environmental change with other socio-economic events that has triggered larger-scale mobility.

In Bolivia, the extensive closure of small-scale mines in the highlands has taken away what used to be a traditional alternative income-generating occupation for local farmers which helped them make it through periods of drought.  In the aftermath of the catastrophic El Nino of 1982, they were left with few alternatives other than moving to other parts of the country. In Senegal, the collapse of international cash crops in the traditionally dry groundnut basin has forced farmers to look for work elsewhere. And in Tanzania, pastoralists affected by floods and animal diseases find it increasingly difficult to access pasture land as this is defined as ‘unused’ and rights sold to large investors; this helps explain the influx of young Maasai pastoralists looking for jobs as watchmen in Tanzania’s towns and cities.

In all three countries, the most vulnerable households are those who do not receive remittances, underscoring the importance of migration. In the poorer areas, remittances are in fact essential for survival, and are often send, or spent, on food.  But remittances can also be used for investment. Some of it may be in agriculture, although this is usually only the case in areas of commercial agriculture and much less so in areas with limited potential, due for example to poor soils and lack of water.

International migrants, on the other hand, prefer to invest in buildings and enterprises in smaller towns, where land is cheaper than in the cities. This is one important reason for the rapid growth of smaller urban centres in many low and middle-income nations. Despite this, small towns often have local governments that do not have the technical capacity, resources and accountability needed to manage sustainable growth that does not compromise natural resources and marginalise poorer groups.

Implications for policy choices

This note has summarised some of the main aspects that need to be taken into account for a better understanding of links between environmental change and migration. From a policy perspective, the key challenge is how to ensure that mobility contributes to adaptation to climate change, while at the same time supporting mitigation efforts.

Attention is needed to address the non-environmental factors that make people more vulnerable to the impacts of climate change. These factors include the management of urbanization to accommodate growing urban populations and avoid the increase of urban poverty and the numbers of people living in areas with high levels of environmental hazards. In rural areas, there is a need to assess and address the impacts of transformations in agricultural production systems and the construction of infrastructure (in many cases and increasingly related to climate change) on the poorest groups. In most instances, these are also the ones who have least representation in policy debates.

Finally, while this note explores mainly internal migration and national and local policy issues, there is clearly a responsibility on the part of high greenhouse gas emitters and industrialised nations to support wide-ranging adaptation efforts in the Global South, and especially community-based initiatives. At the same time, there is a duty to ensure that mitigation initiatives do not result in increased vulnerability and displacement and/or distress migration due to the construction of infrastructure and the expulsion of smallholder farmers from land used for biofuels and biomass.


Final final report of the UK government’s Foresight project on migration and environmental change: http://bis.gov.uk/assets/bispartners/foresight/docs/migration/11-1116-migration-and-global-environmental-change.pdf 

International Institute for Environment and Development: Publications on rural-urban linkageshttp://pubs.iied.org/search.php?tdB=1&k=rural-urban&s=HSWP&w=HS&p=1

Tacoli, Cecilia: ‘Crisis or adaptation?’ published in "Environment and Urbanization", 2009: http://eau.sagepub.com/content/21/2/513.full.pdf+html 

Cecilia Tacoli, International Institute for Environment and Development, London, 2012