Immigration

Immigration is the international movement of people to a destination country of which they are not usual residents or where they do not possess nationality in order to settle as permanent residents. Commuters, tourists, and other short-term stays in a destination country do not fall under the definition of immigration or migration; seasonal labour immigration is sometimes included, however.

Economically, research suggests that migration can be beneficial both to the receiving and sending countries. The academic literature provides mixed findings for the relationship between immigration and crime worldwide. Research shows that country of origin matters for speed and depth of immigrant assimilation, but that there is considerable assimilation overall for both first- and second-generation immigrants.

Discrimination based on nationality is legal in most countries. Extensive evidence of discrimination against foreign-born persons in criminal justice, business, the economy, housing, health care, media, and politics has been found.

The term immigration was coined in the 17th century, referring to non-warlike population movements between the emerging nation states. When people cross national borders during their migration, they are called migrants or immigrants from the perspective of the destination country. In contrast, from the perspective of the country from which they leave, they are called emigrants or outmigrants.

Human migration is the movement by people from one place to another, particularly different countries, with the intention of settling temporarily or permanently in the new location. It typically involves movements over long distances and from one country or region to another. The number of people involved in every wave of immigration differs depending on the specific circumstances.

Historically, early human migration includes the peopling of the world, i.e. migration to world regions where there was previously no human habitation, during the Upper Paleolithic. Since the Neolithic, most migrations (except for the peopling of remote regions such as the Arctic or the Pacific), were predominantly warlike, consisting of conquest or Landnahme on the part of expanding populations.^{[citation needed]} Colonialism involves expansion of sedentary populations into previously only sparsely settled territories or territories with no permanent settlements. In the modern period, human migration has primarily taken the form of migration within and between existing sovereign states, either controlled (legal immigration) or uncontrolled and in violation of immigration laws (illegal immigration).

As of 2015^[update], the number of international migrants has reached 244 million worldwide, which reflects a 41% increase since 2000. The largest number of international migrants live in the United States, with 19% of the world's total. One third of the world's international migrants are living in just 20 countries. Germany and Russia host 12 million migrants each, taking the second and third place in countries with the most migrants worldwide. Saudi Arabia hosts 10 million migrants, followed by the United Kingdom (9 million) and the United Arab Emirates (8 million). In most parts of the world, migration occurs between countries that are located within the same major area. Between 2000 and 2015, Asia added more international migrants than any other major area in the world, gaining 26 million. Europe added the second largest with about 20 million.

In 2015, the number of international migrants below the age of 20 reached 37 million, while 177 million are between the ages of 20 and 64. International migrants living in Africa were the youngest, with a median age of 29, followed by Asia (35 years), and Latin America/Caribbean (36 years), while migrants were older in Northern America (42 years), Europe (43 years), and Oceania (44 years).