What is migration?
The relationship between the numbers of births and deaths (natural change) is not the only factor in population change. The balance between immigration and emigration (net migration) must also be taken into accont, The relative contributions of natural change and net migration can vary both within a particular country and between groups of countries. Migration tends to be subject to distance-decay – the number of migrants declines as the distance between origin and destination increases. Refugees tend to move only short distances; economic migrants travel greater distances.
Types of migration – scale (international, regional, local), direction (rural-urban, LEDC to MEDC), distance (long, short, regional), Decision making (forced – from hazards or for political safety – refugees, voluntary – work, retirement), Cause of movement (economic, social, environmental)
Causes of migration
Migration is more volatile than fertility and mortality. it is affected by changing physical, economic, social, cultural and political circumstances. However, the wish to migrate may not be fulfilled if the constraints are too great. The desire to move within a country is generally inhibited only by economic and social factors. The desire to move to another country is usually constrained by political factors, such as immigration laws.

Examples of migration
The changing nature of international migration
International migrants make up about 3% of the world’s population. Economic conditions, social and political tensions and historical traditions can influence a nation’s level of migration. net migration rates can mask offsetting trendsm such as immigration of unskilled workers and emigration of more-educated residents.
Patterns of international migration have ben changing since the late 1980s. There have been increase in:
· Attempts at illegal, economically motivated migration as a response to legal restrictions
· Those seeking asylum
· Migration between more developed countries, particularly between countries within the EU where restrictions have been removed to allow the free movement of labour
· Short-term migration, as countries increasingly place limits on work permits. It is now common for more developed countries (e.g. the UK and USA) to limit the length of work permits, even for qualified migrants coming from other developed countries
· Movement of migrants between less developed countries, particularly to those where rapid economic development is taking place, for example the countries of the Persian Gulf and the Asian economic growth areas of Singapore and Indonesia

There has been a decline in:
· Legal, long-life migration, particularly from less to more developed countries. Host countries provide fewer opportunities for migrants because the number of available
low-skilled jobs has dropped. Many host countries have also tightened entry requirements and introduced more rigorous monitoring at the point of entry
· The number of people who migrate for life. Man newer migrants want to return home at some point. For example, a common feature of villages in Italy, Portugal and Greece is new hosing built new returnees
· The number of people migrating with the purpose of reuniting family members, as the amount of long-term family separation reduces and many migrants eventually return
Refugees are defined by the UN as persns unable or unwilling to return to their homeland for fear of persecution, based on reasons of race, religion, ethnicity or political opinion, or thise who have been dispalced forcibly by other factors.
By 2003, the UN estimated that there were over 22 million refugees in the world. Many refugees movements are large-volume, non-selective and over short distances. They are often caused by war. Such migrations are often temporary – when the cause of te migration ends, the refugees return to their former homes. At the end of the 20th Century and the beginning of the 21st, major movements have inclued:
· 2 million from Ethiopia, Sudan and Somalia as a result of famine and civil war
· 6 million from Mozambique as a result of famine, civil war and flooding
· 1 million Kurds from northern Iraq fleeing oppression
· 1 million Afghans into neighbouring Pakistan fleeing civil strife and war
· 100,000 Tamils fleeing oppression and civil war in Sri Lanka
· 7,000 residents of Montserrat fleeing a volcanic eruption in the Soufriere Hills
Asylum seekers
One definition of asylum is ‘the formal application by a refugee to reside in a country when they arrive in that country’. The numbers seeking asylum have increased steadily in recent years as countries seek ti curtail immigration.
The prominence of asylum seeking has increased for the following reasons:
· Pressure to migrate from the poorest states is increasing because of economic decline and political instability
· Improved communications enable people to learn more about potential destinations
· In real terms, the cost of transport has declined
· More gangs of traffickers are preying on would-be migrants and offering a passage to a new life
It can be difficult to distinguish between those fleeing from threats to their life and liberty and those seeking to escape poverty and improve their quality of life.