The movement of people has traditionally been part of the social organisation and experiences of many communities around the world. Generally, people move for various reasons and there are many modes and categories of human mobility. While conflicts, persecution and disasters (natural, climate-related or development-induced) have been major causes of displacement and migration, other people move as labour migrants or in response to changing environmental conditions. Migration and displacement are therefore complex phenomena driven by many different interlinked factors. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) confirms that climate change will have significant impacts on human mobility. Increasingly intense and frequent extreme weather events and disasters such as typhoons, floods, droughts and heatwaves as well as slow-onset events like rising sea levels and increasing temperatures all have long-term effects on the health, safety and economic situation of affected people.

The relationship between climate change and human mobility is complex. In the face of gradual shifts in the climate, some people may choose to migrate as a way of adapting. Extreme weather events could force people to move within their own country or flee across borders, while others who feel the need and desire to migrate but do not have the possibility to do so can become ‘trapped’ in vulnerable areas. Climate-induced human mobility functions as an umbrella term that refers to all aspects of movements of people by sudden or slow-onset events related to climate change. In the context of the United Nations Framework Convention on Climate Change (UNFCCC), three types of climate-induced human mobility are differentiated: migration, displacement and planned relocation.

While the exact extent of climate change impacts on migration remains a subject of ongoing debate, there is widespread consensus that climate change has already had – and will undoubtedly continue to have – adverse effects on socio-economic conditions and thus undermines individuals’ and societies’ capacity to manage or adapt to the risks of climate change. Specifically, resilience is reduced as livelihoods are compromised, with adverse impact on food, water and economic security. It is projected that in the near future, growing numbers of people are likely to be displaced or to decide to migrate or relocate as a response. Potential competition for scarce resources in host regions for displaced persons and migrants may heighten the risk of violent conflict, with implications for human security.

What influences a human mobility decision?

The factors influencing a migration decision are complex and climate change has an effect on multiple drivers of migration at different levels. Climate change-related impacts, such as rising sea levels, changing rainfall patterns and increasing temperatures, intersect with existing constraints such as socio-economic, political, demographic and environmental issues, further aggravating existing vulnerabilities and pressures. There may also be other intervening obstacles and facilitators such as political and legal frameworks or social networks on the meso level, and personal and household characteristics such as age, education, and preferences that may influence the decision to move on a micro level (see figure below).

Own diagram based on Foresight Report 2011, p. 21

In addition to their interaction with existing drivers and vulnerabilities, climate change impacts can also be the critical factor in influencing the movement of people. Rising sea levels are making low-lying coastal areas uninhabitable and can lead to loss of territory, which will make moving inevitable. In the case of disaster-induced displacement, movement can often be attributed to a particular disaster, such as a typhoon, as the primary trigger.

In addition to being a catalyst for human mobility, climate change can also prevent it by undermining people’s livelihoods. Many people, particularly those already vulnerable due to existing economic, political or demographic factors, may be unable to migrate due to insufficient financial means, absence of networks of support, social exclusion, limited political rights, conflict or geographic isolation. These ‘trapped populations’ become increasingly vulnerable, as climate change-related harms continue to undermine their livelihoods.

Forecasts: Can we predict how many people will move in the future?

While there is a significant relationship between human mobility and climate change, it is difficult to make reliable estimates. Projections of future numbers vary widely, due to the complexity and multi-causality of human mobility and the uncertainty of the extent of future climate change impacts. There is, however, a general consensus that the number of people moving will likely rise over the coming decades.

Most climate-induced human mobility has until now mainly taken place within national borders and it is likely that this will continue to be the case in the future. The Groundswell Report anticipates that without ambitious global and national action to reduce greenhouse gases and to mitigate the effects of climate change, sub-Saharan Africa, South Asia and Latin America could see more than 140 million people migrating within the borders of their countries by 2050. The majority of internal migration is temporary, and it is likely that people will return to their homes as soon as possible, as is often the case after extreme weather events and natural disasters.

Migration is often assumed to represent a failure to adapt to a changing environment. However, it can also be used as a proactive strategy to cope with climate change. In fact, migration has been a traditional adaptation strategy for centuries and people have engaged in long-term and short-term migration as an adaptive response to climactic stress. For example, the livelihoods of nomadic pastoralist societies have always included mobility as a tool to deal with climactic variability. To understand climate-induced migration as a strategy to prevent and reduce climate risks, it should thus be considered as part of migration processes that have always existed.

Migration should not always be seen as a last resort in the face of negative climate impacts; it can also be a deliberate decision that will enable migrants to reduce their vulnerability to the impacts of climate change. It can be a way to diversify traditional agricultural-based livelihoods: It gives an individual or household a chance to diversify their income source, spread risks and send back remittances to family members, which would, in turn, increase resilience back home.

Managed in the right way, voluntary migration holds great potential as a successful adaptation strategy. Policymakers could consider how they can improve the adaptive capacity of vulnerable households and communities, for example through education and information programmes to allow for migration as an informed choice.

Planned relocation efforts should only be conducted voluntarily and are to be considered as a last resort when safe in situ adaptation or other options have been exhausted. Where it is found to be necessary, planned relocation processes should be designed and implemented with the close involvement of the community and careful attention to community needs, rights and aspirations in order to achieve reduced vulnerability and increased resilience.

Generally speaking, international policy has long given only limited recognition to migration and displacement induced by climate change, disasters and other environmental causes.

However, renewed international efforts have culminated in the recognition of climate change impacts on human mobility under the Cancun Adaptation Framework in 2010.

Specifically, the Cancun Adaptation Framework emphasised the need for critical understanding of and coordination and cooperation on issues of climate change-induced displacement, migration and planned relocation at national, regional and international levels. In 2015, at COP21 in Paris, the Task Force on Displacement was created under the Warsaw International Mechanism for Loss and Damage associated with Climate Change Impacts (WIM) to formulate recommendations for addressing the adverse effects of climate change on displacement.

Other frameworks aimed at strengthening the resilience of people and reducing the adverse effects of climate change on development include:

The Sendai Framework for Disaster Risk Reduction (2015–2030), formulated with the assistance of the United Nations Office for Disaster Risk Reduction (UNDRR, formerly UNISDR) is a non-binding agreement that seeks to tackle disasters and their impacts, including displacements. It aims to do so by minimising climate and disaster impacts in vulnerable countries. In particular, the Sendai Framework recognises migrants and displaced persons as key stakeholders in planning disaster risk reduction.

The 2030 Agenda for Sustainable Development also highlights the management of displacement and migration as crucial for the achievement of the Sustainable Development Goals (SDGs) but makes no direct connection to climate change-induced migration. While SDG 13.1 on climate action calls for strengthening of resilience and adaptive capacity to climate-related hazards and natural disasters in all countries, it does not mention migration or displacement. Despite their recognition of and calls for safe, orderly and regular migration, the SDGs do not explicitly connect migration and climate change.

The Nansen Initiative and the subsequent Platform on Disaster Displacement (PDD) are non-binding, state-led international processes that address the lack of protection for those displaced across borders by climate change-related disasters. The Nansen Initiative was a bottom-up consultative process involving diverse stakeholders in developing recommendations and led to the development and endorsement of the Agenda for the Protection of Cross-Border Displaced Persons (Protection Agenda). The Platform on Disaster Displacement (PDD) has a coordinating function in assisting states to tackle knowledge gaps, promote policy coherence and mainstream human mobility within policy formulation. As the follow-up process to the Nansen Initiative, it is also tasked with implementing the recommendations of the Protection Agenda. The Protection Agenda identifies three priority areas for future action: collecting data and enhancing knowledge; enhancing the use of humanitarian protection measures; and strengthening the management of disaster displacement risks in the country of origin (e.g. through facilitating migration with dignity as a potentially positive way to cope with disasters and climate impacts and improving the use of planned relocation as a preventative or responsive measure to disaster displacement risks).

The Global Compact for Safe, Orderly and Regular Migration (GCM) is rooted in the 2030 Agenda and the New York Declaration for Refugees and Migrants and is perhaps the most comprehensive intergovernmental framework that covers all dimensions of migration, including climate-induced migration. Although the GCM is voluntary and not legally binding, its objectives recognise changing socio-economic and environmental conditions and the implications they may have for migration.

On behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ), the GIZ Global Programme on Human Mobility in the Context of Climate Change (GP HMCCC) is working to support its partners in addressing and better understanding the complex, multi-causal interrelations between different forms of human mobility and climate change, especially in small atoll and island states in the Pacific and Caribbean regions and in the Philippines, but also in sub-Saharan Africa. In collaboration with national and regional partners, non-governmental organisations and universities, the GP HMCCC promotes exchange between all the actors involved. It aims at improving applied knowledge relating to the sustainable management of human mobility in the context of climate change in its partner regions.

With its increasing adverse effects, climate change will continue to have significant impacts on human mobility and be a major influencing factor in people’s decisions to leave their homes. Impacts will include loss of land and livelihoods, and heavy and recurring damage to infrastructure. In some cases, they may involve the loss of territorial integrity, sovereignty, identity and culture. While the negotiations under the United Nations Framework Convention on Climate Change recognises climate-induced migration as an effective adaptation strategy in the Cancun Adaptation Framework, existing international policy frameworks do not provide sufficient assistance and protection for people moving due to the effects of climate change. For example, the 1951 Geneva Refugee Convention and its 1967 Protocol do not recognise climate change as a reason for granting refugee status. Also at national level, there are very few examples of legal frameworks that grant protection to ‘climate migrants’ and support their relocation in line with their needs. At present, most governments and regional organisations in the countries most affected by climate change, as well as international development cooperation, do not have sufficient knowledge and experience to shape a development-oriented approach towards human mobility in the context of climate change. One of the main concerns is a lack of empirical evidence that can explain how much, where, why and over what timeframe human mobility will take place and what future scenarios could look like. Most existing research methodologies fall short of accurately accounting for the complexity of migration decisions. Better and more comprehensive climate migration models are needed to fill this gap. To develop such climate-induced migration scenarios, collecting data on past and current migration patterns is crucial.

More research and better modelling in order to gain an understanding of different mobility patterns and the ways in which they relate to climate-induced shocks and stressors will be critical to planning for the future and for developing strategic and effective policy responses and adaptation measures.

More information on practical examples of activities related to migration and climate change and various publications can be found on this website. See also the following key publications and websites for further reading:

• The Atlas of Environmental Migration
• Groundswell: Preparing for Internal Climate Migration
• Foresight Report: Migration and Global Environmental Change
• Environmental Migration Portal