Too often, overcrowded boats sink, killing dozens or hundreds of people (figure 3.22). In other cases, the Libya coast guard detains migrants and sends them to detention centers that are little better than where they were held by smugglers. People risk their lives to migrate when push and pull forces are strong enough, but long distances can present incredible risk.
Because of the power of distance decay, most international immigration is intraregional. For instance, 52 percent of African migrants live within Africa, 60 percent of Asian migrants live within Asia, and 66 percent of European migrants live within Europe. The only exception to the pattern is with Latin American and Caribbean migrants, 70 percent of whom migrate to North America.
Figure 3.22.Survivors of a Mediterranean Sea crossing arrive in Italy. Forty-nine bodies were found in the overcrowded hold of the smuggler’s boat. Photo by Wead. Stock photo ID: 328040444. Shutterstock.
Physical barriers, both natural and human-built, can also act as intervening obstacles. Natural barriers, such as mountains, rivers, deserts, and oceans, limit the movement of people between places. Likewise, human-built physical barriers, such as walls, can also restrict migration. No doubt there would be more Cuban immigrants in the United States if the countries were not separated by ninety miles of ocean. Likewise, fences, cameras, motion sensors, and other security barriers along the US-Mexico border severely limit the number of people crossing there (figure 3.23).
In addition, government immigration policies can create intervening obstacles. Restrictive policies in destination countries and in-transit countries can limit the flow of migrants. Conversely, open immigration policies, or policies that actively recruit migrants, will increase flows. More on immigration policies is discussed later in this chapter.
The concept of cultural distance can also play a role in migration patterns, as people tend to move between places with similar cultures. As discussed in the section on push and pull forces, flows of migrants tend to be greater between places with the same language and religion (figure 3.24). English speakers tend to migrate more between the United States, Great Britain, Australia, New Zealand, and Canada, while Arabic speakers move more between the countries of North Africa and the Middle East. This also holds true for former European colonies. A significant number of migrants from the former French colonies of Algeria and Vietnam migrated to France, while the same occurred with Great Britain and its former colonies, such as India, Pakistan, Hong Kong, and Nigeria.
Figure 3.23.Physical barriers to migration. Photo of the border fence and US Border and Customs Protection patrol. The border wall separating San Diego, California (left), and Tijuana, Mexico, seen in ArcScene. Explore this scene at https://arcg.is/1PWeSW. Border fence photo by mdurson. Stock photo ID: 595401863. Shutterstock. Border wall image from ArcScene, Esri.
Figure 3.24.Cultural distance and migration. Places with similar cultural characteristics, such as language, will have more spatial interaction, “shortening” the distance between them. A Lebanese-Moroccan food restaurant in Paris. Photo by Hadrian. Stock photo ID: 275980151. Shutterstock.
The gravity model
The gravity model adds another component to the analysis of migration flows: size. Based on the ideas of Isaac Newton, the gravity model states that both distance and size will influence the flow of migrants between two places. The degree of migration between two places is proportional to the population size of each place and inversely proportional to distance. In essence, places with large populations that are close to each other will have large migration flows between them, while places with small populations that are far from each other will have small migration flows between them. Mexico and the Philippines are both developing countries and have populations around 100 million, yet Mexico sends many more migrants to the US. This is because Mexico is much closer, so migration is less costly in terms of time and money. By contrast, China sends more migrants to the US than does Nicaragua. Nicaragua is much closer to the United States, but the large population of China means that there is more spatial interaction with the US in terms of migration. Out of a population of nearly 1.4 billion people, even a small emigration rate represents many migrants.
Evidence of the gravity model at work can be seen in interstate migration within the United States. Using the example of Nebraska, located near the center of the country, we can see that more immigrants came from nearby Iowa and Missouri, two states that also have populations larger than many other surrounding states (figure 3.25). These migration flows would be predicted by the model, based on both distance and population size. Being nearby, people from these states will have more information on the economic opportunities in Nebraska, and the costs associated with moving and with return visits to friends and family will be lower. At the same time, we see evidence of population size playing a large role in where immigrants to Nebraska came from. Both California and Texas were the origins of many of these immigrants. With their large populations, these states have a larger pool of potential emigres. Inevitably, some of the immigrants will relocate to other states, some nearby but others farther away.
Figure 3.25.The gravity model: Migration to Nebraska. Data source: US Census.
Social networks and information flows
Distance, intervening obstacles and population size influence migration patterns, but these flows are further complicated by social networks and information flows from individuals and the media that connect specific places. When migrants make the decision to leave a place because of push forces, they do not consider all potential destinations. Rather, they base their decisions on available information. This information is inherently incomplete and is dependent on social connections and media sources. Information flows are enhanced when places have economic or political ties. For example, linkages formed through trade and investment, colonization and political influence, and cultural connections can facilitate information flows and lead to migration.
Media information can come from advertisement campaigns that promote the economic benefits of a place as well as images in newspapers, magazines, television, and online (figure 3.26). Many people around the world have seen media images of the United States and Western Europe and their high levels of economic development. Partially due to these images, there are always large numbers of migrants who desire to move to these places.
Media images also shape migration patterns at more regional and local scales. For example, many Zimbabweans have migrated to South Africa on the basis of information that the economic situation there, while difficult, was more stable than in Zimbabwe. Likewise, within the United States, media information flows impact migration. Many Californians have migrated to Texas, partially because of Texan media campaigns promoting the state as an affordable destination with a strong pro-business government. On the other hand, Texans also move to California, no doubt in part because of media images of beaches and a year-round pleasant climate.
Aside from media images, social connections also play a powerful role in information flows and resulting migration patterns. Pioneer migrants are the first migrants to arrive in a new place. These trailblazers may arrive for any number of reasons: for university studies, a chance job opening, a romantic partner, or a search for novelty and adventure. They tend to be young and single, without family and financial responsibilities that tie them to their home place. These pioneer migrants then provide information to friends and family. Through letters, phone calls, email, and social media, they can share information on their lives in a new location, including job and wage information and quality of life. If those friends and relatives
