Climate mobility, explained

Climate immobility describes people who stay in places exposed to climate risk, either because they cannot leave or because they choose not to.

• Trapped populations: people who do not move, yet live in areas under threat, and who are at risk of becoming “trapped” or having to stay behind, where they are more vulnerable to environmental shocks and impoverishment (IOM, 2019). This applies in particular to poorer households, who may lack the money, documents, health or social networks they would need to move. It can include older people, people with disabilities, and people who depend on the land for a living.
• Voluntary immobility: people who choose to stay because of their ties to land, culture, community or identity, such as ancestral links with their land, even when the risks are high.

Good policy considers both groups. It makes staying safer through adaptation, and makes moving possible for those who need or want to.

Climate migration is one form of climate mobility.

IOM defines climate migration as the movement of people who, mainly because of sudden or progressive change in the environment due to climate change, are obliged to leave their usual home, or choose to do so, either temporarily or permanently, within a country or across an international border. “Climate mobility” is a broader, umbrella term. Like “human mobility”, it also covers displacement, planned relocation of whole communities, temporary and circular movement, and people who cannot or do not move. The Institute uses “mobility” because policies that look only at migration can miss many of the people affected.

Because framing climate mobility as migration alone can leave out many of the people affected.

Public discussion often presents climate mobility either as a large movement of people across borders, or as a humanitarian emergency to be dealt with once people have been displaced. Both frames focus attention on movement, and on the moment at which it becomes visible. They can leave out people who stay, people who cannot leave, and the communities that receive newcomers.

The Institute therefore approaches climate mobility through the lens of habitability: whether places, and the people in them, can continue to sustain a safe and dignified life and livelihoods as the climate changes. The question for policy becomes: what will it take for people to continue to live a safe and dignified life, whether they stay or move?

Seen this way, climate mobility calls for two linked pillars of policy response that operate together: helping people to stay safely where they are, and making movement safe, lawful and dignified when it happens. Choice is the measure of success: people should be able to remain in safety or move in safety, on terms they have a part in deciding.

No. The Climate Migration Council and others distinguish four situations, each of which may call for a different response.

• Migration as adaptation: people move, often temporarily, to reduce risk and, in some cases, to diversify income.
• Forced displacement: people are forced or obliged to leave their homes.
• Trapped populations: people remain in high-risk places because they cannot move.
• Politically exploited movement: movement, or stories about it, used by others for strategic, criminal or political ends.

Because it is already happening, and governments that plan ahead are generally better placed than those that only react.

The main risk is not movement itself, but the strain on the systems that allow people to stay safely, adapt locally or move by choice. Without planning, that strain can fall on housing and services, test social cohesion, and create openings for smuggling and exploitation. Well managed, climate mobility can be a form of adaptation. It can help meet labour shortages, support regional stability and protect lives. Many of the tools governments need already exist, and need coordinating and adjusting rather than reinventing. Acting early can also cost less: studies find that investment in resilience typically returns between two and ten times its cost.

One approach is to use published indicators applied to whole countries or regions, rather than detailed assessments of individual people.

Established indices such as the Notre Dame Global Adaptation Initiative (ND-GAIN) Country Index and the EU's INFORM Climate Change Risk Index rank countries on exposure, sensitivity and capacity to adapt, and are updated regularly. Governments can combine these with their own foreign ministry country assessments and with data from national weather and emergency authorities.

Assessing whole countries or regions, rather than each individual, can be quicker, cheaper and more consistent. It also avoids asking people to prove that climate change alone caused them to move, which is very difficult to do.

Planned relocation should be a last resort, carried out with communities rather than imposed on them.

Human rights law protects freedom of movement and choice of residence, and protects people against arbitrary displacement and forced eviction. Under the UN Declaration on the Rights of Indigenous Peoples, Indigenous peoples should not be relocated from their lands without their free, prior and informed consent. Fiji’s national guidelines, for example, provide for communities to be consulted and involved throughout.

This is different from a short-term emergency evacuation, where there is an immediate risk to life. Long-term relocation rarely succeeds without the community’s agreement, so meaningful participation matters both legally and in practice.

The legal risk is generally thought to be lower than often feared, but the practical risks are real.

Rising seas have raised questions about the future of low-lying island states. No state has yet ceased to exist because its territory was submerged. Pacific Islands Forum leaders declared in 2023 that statehood and sovereignty will continue despite sea-level rise, Tuvalu has written this into its constitution, and the International Court of Justice’s 2025 advisory opinion indicated that a state would not necessarily lose its statehood if one of its elements, such as territory, disappeared.

The more immediate risk is practical. People who lose their identity documents in a disaster may be unable to prove their nationality, and regional free movement agreements often do not cover stateless people and non-nationals. Reissuing documents quickly after a disaster is an important protection.

All of them, in different ways.

• National governments have the primary responsibility to protect and assist people displaced within their own borders, as reflected in the UN Guiding Principles on Internal Displacement.
• Local and city governments are often the first to respond and the places that host newcomers, so they need funding and plans in place.
• Destination countries are bound by obligations they already have, including not returning people to serious harm, and decide on their own admission routes.
• The international community shares responsibility through climate finance, development cooperation and regional agreements.

Within any one government, responsibility is usually spread across many ministries. For that reason, the Institute recommends that the centre of government (the Cabinet Office or equivalent) adopt a working definition of climate mobility and assign responsibilities across departments, so that each is clear about its role. This is best done early, well before a crisis.

When a state is unable or unwilling to protect people from serious and foreseeable harm.

This can happen suddenly, when a disaster overwhelms the state’s ability to respond, or gradually, as slow onset change affects water, food, income or safety. It can also happen selectively, when some groups are left out of protection or adaptation support.

In assessing a person’s situation, decision-makers can ask whether the country of origin has provided protection or adaptation support that is meaningful in that person’s own circumstances. A national plan on paper may not be enough.

There is no single agreed measure, but there are useful indicators.

Physical indicators include extreme heat and humidity, freshwater availability and salinisation, how often coastal flooding and erosion happen, and changes in crop yields. Social indicators matter just as much: whether people have access to income, services, housing and safety.

Because habitability is a matter of degree rather than a threshold, no single measure will show when a place has become uninhabitable. For deciding who is eligible for support or a pathway, the Institute suggests that governments use a transparent set of criteria, such as a country falling below a set vulnerability score, or a national climate agency designating an area as facing “serious and reasonably foreseeable uninhabitability”. Waiting until a place has become uninhabitable would be too late.

It can start alone, but it can achieve more with partners.

Much of what the Institute recommends is within the UK’s own control: guidance for decision-makers, adapting existing visa routes, domestic housing and funding reform, and building climate mobility into intelligence and development planning.

Results are likely to be stronger with partners, for example through bilateral labour agreements, support for regional free movement agreements, multilateral climate finance and the Platform on Disaster Displacement.

Several bodies of law can apply together, depending on where a person moves and why.

• Domestic immigration law covers visas, leave to remain and temporary protection. This is where most decisions are made.
• International human rights law includes the right to life and the prohibition on returning people to serious harm (non-refoulement), under the International Covenant on Civil and Political Rights (ICCPR) and the European Convention on Human Rights. It protects everyone who moves in the context of environmental change.
• Internal displacement frameworks include the UN Guiding Principles on Internal Displacement, which cover people displaced by disasters, and, in Africa, the binding Kampala Convention.
• Regional and bilateral agreements include free movement protocols and treaties such as the Falepili Union.

“Climate migrant” is not a recognised legal term.

A person’s right to enter or stay is decided under domestic law. In the UK, the Home Office makes these decisions, subject to appeal to the immigration tribunals and higher courts, as it does now. The question for those courts is whether a person qualifies for leave to enter or remain in the UK under an existing route or form of protection, not whether they are a “climate migrant”.

International bodies play a more limited role. The European Court of Human Rights hears individual cases under the European Convention on Human Rights. The views of the UN Human Rights Committee, such as in Teitiota v New Zealand, and the International Court of Justice’s 2025 advisory opinion are influential, but they are not binding judgments in individual cases.

No. Existing protections still apply, but they are uneven and were not designed with climate change in mind.

In Teitiota v New Zealand, the UN Human Rights Committee recognised that the effects of climate change may expose people to a real risk to their right to life, which could prevent a state from returning them. The International Court of Justice indicated in 2025 that non-refoulement obligations can apply in this context.

But the bar is high, slow onset harm is difficult to prove, and protection may come only at a very late stage. For this reason, the Institute recommends clear guidance for decision-makers, and planned routes that do not depend on people reaching a point of crisis.

More than many people think. Most were not designed for climate mobility, but they can be adapted.

• Labour migration routes: potentially one of the most promising tools for safe movement at scale, especially where routes deliberately include people from climate-vulnerable regions.
• Humanitarian visas: for example, Argentina's proposed visa for people displaced by disasters.
• Temporary protection: for example, US Temporary Protected Status, which has been designated after disasters such as Hurricane Mitch.
• Free movement agreements: for example, in the Caribbean, West Africa and East Africa, where eligibility depends on nationality, not on the reason for moving.
• Bilateral treaties: for example, the Australia–Tuvalu Falepili Union.

“Habitability” has no set definition in law. It is usually understood through human rights.

• In law: the question is whether people can enjoy the right to life with dignity, including access to water, food, housing and health. In Teitiota, the UN Human Rights Committee accepted that a country could become unfit to live in, and that returning people before that point could still breach their rights.
• In policy: governments may use risk criteria, land-use designations such as “no-build” zones, managed retreat decisions and vulnerability indices.
• In practice: communities often reach their own conclusions first, as they see water turn salty, harvests fail and homes flood repeatedly. Policy should take account of those signals.