UKCCMC report summaries synthesise key documents on the topic of climate change and migration. They do not intend to provide analysis. For analysis on current issues and policy see the Blog section of this website. 

Migration and global environmental change is the first major study by the UK government into the topic of climate change and migration. One of the key findings of the report is that climate change could make migration harder. The authors argue that the effects of climate change could leave some of the most vulnerable people “trapped” and unable to move out of high risk areas. As climate change begins to negatively impact livelihoods many people will find themselves poorer and without the resources to move. Findings also suggest that people are migrating into areas of high risk, for example towards coastal cities and into river deltas. 


Summary: Migration and Global Environmental Change, BIS Foresight Programme

  • It is very difficult to distinguish “environmental migrants” from other migrants as the factors that cause migration are complex and interact with each other in unexpected ways.
  • However we do know that people are moving into areas of high risk (towards coasts and deltas) and that environmental change could cause economic changes that could “trap” some people and prevent them from moving.
  • Policies are needed that will a) reduce the risk of displacement by increasing resilience b) protect potential migrants using existing legal frameworks, good urban planning and policies to reduce the risk of conflict c) allow people to migrate as a way of adapting to change.

The relationship between global environmental change and migration

Identifying a group of people as “environmental migrants” is difficult or nearly impossible. This is because identifying environmental change as a sole or key factor in a migration decision is very difficult now, and may become even harder in the future. But environmental change will influence migration through existing migration drivers. For example, economic and social factors are known key factors in migration and we can expect that environmental change will influence a number of economic and social drivers. But environmental change will influence some of these drivers more than others.

Several areas of environmental change will influence these drivers: climate related (sea level, storm intensity, rainfall change, temperature change, change is atmospheric chemistry, glacial melt) and non-climatic (land degradation, marine degradation). However there is a lot of uncertainty here, this comes from uncertainly in the modelling of climate impacts and uncertainty around policy response to these threats.

Other drivers will mean that migration will continue regardless of climate change, but the changing climate will expose new people to new risks from natural hazards – the response to which may be migration. This migration can be planned or forced, but planned migration may be one of the best solutions to increased exposure to risk. There is a level uncertainty here, but broad trends and patterns in migration have been identified and modelled.

In spite of this uncertainty two key risks are clear:

  • Climate change may make migration harder. As livelihoods are affected, migrating (which can be expensive) becomes harder. This may result in people becoming “trapped” in high risk areas. Policy needs address people not moving as much as it needs to address people moving.
  • Environmental change is likely to cause people to move towards areas of high risk – e.g towards coastlines and into deltas. Existing rural to urban migration also means people are moving towards coastal areas.

Several areas are especially at risk. 1) dry lands 2) coastal zones and 3) mountain regions. The report looks at these risks through the a lens of possible future scenarios. The scenarios have different levels of economic growth and governance. This creates four scenarios: a) high growth / low governance b) high growth / high governance c) low growth / low governance d) low growth / high governance. The risks and possible migration patterns differ greatly between regions and which scenario is assumed. It is also clear that there is not a straightforward relationship between environmental change and migration.

This complexity is particularly apparent with the example of mountain regions. Livelihoods in mountain regions are very dependent on ecosystem services, making them vulnerable. However people are already leaving these areas in large numbers. Research indicates this is mainly to find work, but slow and rapid onset environmental hazards are the second and third most common reason stated. Environmental change is also causing migration into, as well as out of, mountain regions. Similar complexities exist in coastal zones,  where economic factors are causing people to move into those areas. Dry lands are more clear cut: there are clear examples of large numbers of people leaving areas as a result of environmental change, for example 100,000 people moved as the Aral sea desiccated. However there is still a complex interaction of factors:  dry lands have particularity high levels of temporary season migration and it is hard to disentangle this from other factors.

The volume and pattern of people migrating is likely to change in the future. Even though it is difficult to pick apart which of these changes are caused by environmental change, it is still clear that these changes will present a mixture of familiar and unfamiliar policy challenges. The report divides policy challenges into:

  • operation challenges: practical, on the ground responses. For example impacts on the economy, human security and social protection. How will cities protect increasing numbers of vulnerable people? How will a region adapt for increased flood risk?
  • geopolitical challenges: difficulties that might result between governments at an international level. For example how would governments respond to a large, unplanned migration across an international border? How might governments respond to a migration across a border if it becomes impossible for people to return?

The report argues that most of the measures needed to respond to operational challenges already exist, however governments might well not implement them properly. They do not represent entirely new problems. Some, but not all, of the geopolitical challenges are new and may represent unfamiliar territory to policy makers and diplomats.

The report identifies three broad areas of policy response.
1. Measuring and reducing environmental change. Policies that aim to reduce environmental change, like the UNFCCC regime and various international frameworks on land degradation, have had a limited or unclear impact on levels of migration. More promising are policies and practices that try to deal with rapid onset events, such cyclone forecasting and flood protection. However the affect of these polices is still not well understood. The most important polices will focus on building long term resilience. Examples include subsided insurance against rapid onset events and long term agricultural development.

2. Planning and responding. There are legal “gaps” in the protection of people displaced by environmental change. However a new legal framework to protect “climate refugees” is unlikely to be the answer. Instead existing international frameworks such as the Guiding Principles on Internal Displacement and other existing policies should be adapted.

3. Cities are in a difficult “double jeopardy” situation. Rural to urban migration means city populations are rising. But cities (especially coastal and delta cities) are particularly at risk. However the report cautions against restricting further rural to urban migration, as this may leave people trapped in rural areas exposed to other serious risks. Therefore cities must: 1. plan for future climate change risks, for example flood defence plans need to stretch 50-60 years ahead and accommodate predicted levels of sea level rise. 2) Fresh water plans need to be put in place, these plans must account for likely hydrological changes and increasing population. The report argues that technical and engineering solutions to these already exist. 3) Planning and zoning policy must prevent “sprawl” into  high risk areas 4) Migrants are often the most vulnerable people in cities. Policies that will reduce this vulnerability include job creation programmes and good urban governance.

Policies also need to be put in place in advance to tackle conflict and unrest that could result from changing migration patterns. This means building additional physical infrastructure – especially housing and access to fresh water. Evidence indicates these are often causes of tension between existing a new residents. “Informal urban housing” has been shown to create no-go-zones and crime hotspots. Building housing with good access to transport, services and water has been shown to reduce these problems.

4. Planned migration as adaptation. Facilitating people to move out of areas of high risk should become a key response to environmental change. It is effective for a number of reasons: some people leaving reduces pressure on resources allowing other people to stay, it diversifies household income reducing other economic risks, new labor can aid economic growth in destination countries. However there are social and emotional costs to this kind of migration which should not be ignored.  A carefully planned movement is better than hasty one, moving predominantly agricultural populations to new areas of fertile land is especially difficult. Facilitating future rural to urban migration should also considered part of adaptation strategies.

The financial cost of inaction is likely to be far higher than the cost of implementing the policy recommendations contained in the report. All of the above policy responses need to be begin now. Most them require years (or decades) to deliver.

UKCCMC report summaries synthesise key documents on the topic of climate change and migration. They do not intend to provide analysis. For analysis on current issues and policy see the Blog section of this website. 

Migration and global environmental change is the first major study by the UK government into the topic of climate change and migration. One of the key findings of the report is that climate change could make migration harder. The authors argue that the effects of climate change could leave some of the most vulnerable people “trapped” and unable to move out of high risk areas. As climate change begins to negatively impact livelihoods many people will find themselves poorer and without the resources to move. Findings also suggest that people are migrating into areas of high risk, for example towards coastal cities and into river deltas. 


Summary: Migration and Global Environmental Change, BIS Foresight Programme

  • It is very difficult to distinguish “environmental migrants” from other migrants as the factors that cause migration are complex and interact with each other in unexpected ways.
  • However we do know that people are moving into areas of high risk (towards coasts and deltas) and that environmental change could cause economic changes that could “trap” some people and prevent them from moving.
  • Policies are needed that will a) reduce the risk of displacement by increasing resilience b) protect potential migrants using existing legal frameworks, good urban planning and policies to reduce the risk of conflict c) allow people to migrate as a way of adapting to change.

The relationship between global environmental change and migration

Identifying a group of people as “environmental migrants” is difficult or nearly impossible. This is because identifying environmental change as a sole or key factor in a migration decision is very difficult now, and may become even harder in the future. But environmental change will influence migration through existing migration drivers. For example, economic and social factors are known key factors in migration and we can expect that environmental change will influence a number of economic and social drivers. But environmental change will influence some of these drivers more than others.

Several areas of environmental change will influence these drivers: climate related (sea level, storm intensity, rainfall change, temperature change, change is atmospheric chemistry, glacial melt) and non-climatic (land degradation, marine degradation). However there is a lot of uncertainty here, this comes from uncertainly in the modelling of climate impacts and uncertainty around policy response to these threats.

Other drivers will mean that migration will continue regardless of climate change, but the changing climate will expose new people to new risks from natural hazards – the response to which may be migration. This migration can be planned or forced, but planned migration may be one of the best solutions to increased exposure to risk. There is a level uncertainty here, but broad trends and patterns in migration have been identified and modelled.

In spite of this uncertainty two key risks are clear:

  • Climate change may make migration harder. As livelihoods are affected, migrating (which can be expensive) becomes harder. This may result in people becoming “trapped” in high risk areas. Policy needs address people not moving as much as it needs to address people moving.
  • Environmental change is likely to cause people to move towards areas of high risk – e.g towards coastlines and into deltas. Existing rural to urban migration also means people are moving towards coastal areas.

Several areas are especially at risk. 1) dry lands 2) coastal zones and 3) mountain regions. The report looks at these risks through the a lens of possible future scenarios. The scenarios have different levels of economic growth and governance. This creates four scenarios: a) high growth / low governance b) high growth / high governance c) low growth / low governance d) low growth / high governance. The risks and possible migration patterns differ greatly between regions and which scenario is assumed. It is also clear that there is not a straightforward relationship between environmental change and migration.

This complexity is particularly apparent with the example of mountain regions. Livelihoods in mountain regions are very dependent on ecosystem services, making them vulnerable. However people are already leaving these areas in large numbers. Research indicates this is mainly to find work, but slow and rapid onset environmental hazards are the second and third most common reason stated. Environmental change is also causing migration into, as well as out of, mountain regions. Similar complexities exist in coastal zones,  where economic factors are causing people to move into those areas. Dry lands are more clear cut: there are clear examples of large numbers of people leaving areas as a result of environmental change, for example 100,000 people moved as the Aral sea desiccated. However there is still a complex interaction of factors:  dry lands have particularity high levels of temporary season migration and it is hard to disentangle this from other factors.

The volume and pattern of people migrating is likely to change in the future. Even though it is difficult to pick apart which of these changes are caused by environmental change, it is still clear that these changes will present a mixture of familiar and unfamiliar policy challenges. The report divides policy challenges into:

  • operation challenges: practical, on the ground responses. For example impacts on the economy, human security and social protection. How will cities protect increasing numbers of vulnerable people? How will a region adapt for increased flood risk?
  • geopolitical challenges: difficulties that might result between governments at an international level. For example how would governments respond to a large, unplanned migration across an international border? How might governments respond to a migration across a border if it becomes impossible for people to return?

The report argues that most of the measures needed to respond to operational challenges already exist, however governments might well not implement them properly. They do not represent entirely new problems. Some, but not all, of the geopolitical challenges are new and may represent unfamiliar territory to policy makers and diplomats.

The report identifies three broad areas of policy response.
1. Measuring and reducing environmental change. Policies that aim to reduce environmental change, like the UNFCCC regime and various international frameworks on land degradation, have had a limited or unclear impact on levels of migration. More promising are policies and practices that try to deal with rapid onset events, such cyclone forecasting and flood protection. However the affect of these polices is still not well understood. The most important polices will focus on building long term resilience. Examples include subsided insurance against rapid onset events and long term agricultural development.

2. Planning and responding. There are legal “gaps” in the protection of people displaced by environmental change. However a new legal framework to protect “climate refugees” is unlikely to be the answer. Instead existing international frameworks such as the Guiding Principles on Internal Displacement and other existing policies should be adapted.

3. Cities are in a difficult “double jeopardy” situation. Rural to urban migration means city populations are rising. But cities (especially coastal and delta cities) are particularly at risk. However the report cautions against restricting further rural to urban migration, as this may leave people trapped in rural areas exposed to other serious risks. Therefore cities must: 1. plan for future climate change risks, for example flood defence plans need to stretch 50-60 years ahead and accommodate predicted levels of sea level rise. 2) Fresh water plans need to be put in place, these plans must account for likely hydrological changes and increasing population. The report argues that technical and engineering solutions to these already exist. 3) Planning and zoning policy must prevent “sprawl” into  high risk areas 4) Migrants are often the most vulnerable people in cities. Policies that will reduce this vulnerability include job creation programmes and good urban governance.

Policies also need to be put in place in advance to tackle conflict and unrest that could result from changing migration patterns. This means building additional physical infrastructure – especially housing and access to fresh water. Evidence indicates these are often causes of tension between existing a new residents. “Informal urban housing” has been shown to create no-go-zones and crime hotspots. Building housing with good access to transport, services and water has been shown to reduce these problems.

4. Planned migration as adaptation. Facilitating people to move out of areas of high risk should become a key response to environmental change. It is effective for a number of reasons: some people leaving reduces pressure on resources allowing other people to stay, it diversifies household income reducing other economic risks, new labor can aid economic growth in destination countries. However there are social and emotional costs to this kind of migration which should not be ignored.  A carefully planned movement is better than hasty one, moving predominantly agricultural populations to new areas of fertile land is especially difficult. Facilitating future rural to urban migration should also considered part of adaptation strategies.

The financial cost of inaction is likely to be far higher than the cost of implementing the policy recommendations contained in the report. All of the above policy responses need to be begin now. Most them require years (or decades) to deliver.

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