What counts as migration?

Migration is the movement of people to live in a new place, usually crossing a defined boundary. Geographers classify it along several axes:

• Voluntary vs forced — voluntary migrants choose to move (usually for work or family); forced migrants are compelled to move by war, persecution or disaster.
• Internal vs international — internal migration stays within a country (e.g. rural to urban); international migration crosses a national border.
• Permanent, temporary or seasonal — a permanent move is intended to last; temporary and seasonal moves (e.g. agricultural labour) are time-limited.

Key distinction: a migrant is someone who changes their usual place of residence. The UN commonly counts a long-term international migrant as a person who moves country for at least one year.

Migrants, refugees, asylum seekers & IDPs

These terms have precise legal meanings under UN and UNHCR definitions and must not be used loosely:

• Economic migrant — a person who moves voluntarily mainly to improve their living or working conditions.
• Refugee — a person forced to flee across an international border owing to a well-founded fear of persecution, conflict or violence (1951 Refugee Convention). They are recognised and protected in international law.
• Asylum seeker — someone who has applied for refugee protection in another country and is awaiting a decision.
• Internally displaced person (IDP) — forced to flee their home but who has not crossed a border and so remains within their own country.

Why it matters: refugees and asylum seekers have specific rights (including non-refoulement — not being returned to danger). Economic migrants do not have those protections, which is why the categories are politically contested.

Which category?

Migration within global systems

Migration is one of the great flows — alongside trade, capital and information — that bind places into a single, interdependent global system. Movements of people create ties of interdependence between source and host areas:

• Labour moves from areas of surplus to areas of shortage, helping to balance the global economy.
• Remittances and skills flow back to source areas, so both ends of the flow depend on the movement continuing.
• Flows are uneven and switchable: policy, conflict or economic shocks can redirect them, and disruption at one end has consequences at the other.

Systems thinking: treat migration as inputs (drivers), flows (movement and networks) and outputs (impacts and feedback). This helps you evaluate how a change in one place ripples through the whole system.

Push-pull, Lee's model & Ravenstein

Migration decisions are shaped by push factors at the origin, pull factors at the destination, and intervening obstacles in between:

• Ravenstein's laws (1885) — early generalisations: most migrants move short distances; migration proceeds in steps; each flow produces a counter-flow; long-distance migrants head for large centres; economic motives dominate.
• Lee added that migration also depends on intervening obstacles and on personal factors (age, education, perception).

Reading Lee's model

Push, pull or obstacle?

Tap a factor, then tap the box it belongs in within Lee's model.

The gravity model, corridors & chain migration

Flows are not random. Some routes carry huge numbers of people and become established migration corridors.

• Gravity model — predicts that the flow between two places is larger when the places are more populous, and smaller when they are further apart. Interaction is proportional to size and inversely related to distance.
• Chain migration — early migrants establish a foothold, then relatives and neighbours follow along the same route, reinforcing a corridor over time.
• Migrant networks — social ties of information, money and support that lower the cost and risk of moving, so networks tend to make migration self-sustaining.

Link to Lee: networks act like a negative intervening obstacle. By supplying jobs, housing and information they reduce the friction of distance, which is why established corridors persist even when original push factors fade.

Why corridors persist

Remittances & development

Remittances are the money that migrants working abroad send back to their families in the source area. They are one of the largest financial flows reaching lower-income countries.

• Household level — remittances raise incomes, fund schooling, healthcare and housing, and can lift families out of poverty.
• National level — they bring in foreign currency and can exceed aid flows, but they are unevenly distributed and can create dependency.
• Feedback — a strong remittance flow can encourage further migration from the same community, reinforcing the corridor.

Evaluate: remittances support development but rarely transform an economy alone; losing skilled workers (a brain drain) may offset the gains, though returning migrants can bring back skills and capital (a brain gain).

Your turn — net migration

Your turn — net migration rate

Impacts on source & host areas

Migration reshapes both ends of the flow across several dimensions. Impacts can be positive or negative depending on scale, rate and management:

• Demographic — source areas lose young adults (ageing left behind); host areas gain working-age people and often a higher birth rate.
• Economic — hosts fill labour shortages and gain taxes and skills; sources gain remittances but may suffer a brain drain.
• Social & cultural — greater diversity and cultural exchange in host areas, but potential pressure on housing and services, and risk of tension or segregation.
• Political — migration can dominate debate, shape immigration policy and strain international relations.
• Environmental — rapid urban in-migration can strain water, land and infrastructure at the destination.

Exam tip: always split impacts source vs host and short vs long term, and note that the same flow can be beneficial and harmful at once.

Demographic dividend & ageing

Migration changes the age structure of populations, with major economic consequences:

• Demographic dividend — when a large share of the population is of working age relative to dependents, a country can enjoy faster economic growth. Immigration of young workers can boost this ratio in the host.
• Ageing — many high-income countries face ageing populations and shrinking workforces; inward migration of young adults can help support pensions and services.
• Source-area ageing — losing young adults can leave the origin with a higher proportion of elderly and children (a higher dependency ratio).

Nuance: a demographic dividend is not automatic. It only pays off if there are enough jobs, education and investment to employ the working-age population productively.

Your turn — foreign-born share

Age structure effects

Match the term to its meaning

Tap a definition on the left, then its matching term on the right.

Managing migration & sovereignty

States try to manage migration to balance economic needs, security and public opinion:

• Border and visa policy — points-based systems, quotas, work permits and border controls regulate who may enter and stay.
• National sovereignty — states have the right to control their own borders and decide who enters their territory.
• International obligations — but they are also bound by agreements such as the 1951 Refugee Convention, including non-refoulement.

Core tension: managing migration means reconciling sovereignty (the right to control borders) with international obligations to protect those fleeing danger. This tension runs through nearly every migration policy debate.

The big ideas to know

You have covered the whole of Global Migration within Global Systems. Press Finish to see your score.